Journeys with Emperors: Tracking the World's Most Extreme Penguin 9780226824390

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Journeys with Emperors

...

Journeys with Emperors ... Tracking the World’s Most Extreme Penguin

Gerald L. Kooyman and Jim Mastro Foreword by Jessica Ulrika Meir

T h e U n i v er si t y of Ch ic ago Pr e ss Ch ic ago a n d Lon don

The University of Chicago Press, Chicago 60637 The University of Chicago Press, Ltd., London © 2023 by Gerald L. Kooyman and Jim Mastro Foreword © 2023 by Jessica Ulrika Meir All photos and images by G. Kooyman, except where otherwise indicated All rights reserved. No part of this book may be used or reproduced in any manner whatsoever without written permission, except in the case of brief quotations in critical articles and reviews. For more information, contact the University of Chicago Press, 1427 E. 60th St., Chicago, IL 60637. Published 2023 Printed in the United States of America 32 31 30 29 28 27 26 25 24 23

1 2 3 4 5

ISBN-13: 978-0-226-82438-3 (cloth) ISBN-13: 978-0-226-82439-0 (e-book) DOI: https://doi.org/10.7208/chicago/ 9780226824390.001.0001 Library of Congress Cataloging-in-Publication Data Names: Kooyman, Gerald L., author. | Mastro, Jim, 1953– author. Title: Journeys with emperors : tracking the world’s most extreme penguin / Gerald L. Kooyman and Jim Mastro. Description: Chicago : The University of Chicago Press, 2023. | Includes bibliographical references and index. Identifiers: LCCN 2023006617 | ISBN 9780226824383 (cloth) | ISBN 9780226824390 (ebook) Subjects: LCSH: Emperor penguin—Antarctica. | Emperor penguin—Behavior. Classification: LCC QL696.S473 K658 2023 | DDC 598.4709989—dc23/ eng/20230223 LC record available at https://lccn.loc.gov/2023006617 ♾ This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper).

To my wife, Melba, who has experienced every polar and elsewhere expedition, read and proofread every word of most journal papers as well as this book, and raised two boys as a single, working mom while I was in absentia in the field; and to those two boys, Carsten and Tory, who until they were skilled enough to go into the field, were without their father much of the time. Jer ry Kooyma n To my coauthor, Jerry Kooyman, consummate scientist and dear friend, whose scientific rigor and creativity forever changed marine biology, and whose curiosity and passion about the natural world and the animals that inhabit it are a constant source of inspiration to me. Ji m Ma st ro

70°

Ad 71°

mi

ral

ty

Ra

Robertson Bay Cape Adare

ng

e

n

d

Cape Roget 72°

w a

Cape Washington

l

B

k

0m 40

Drygalski Ice Tongue Franklin Island

o

r

76°

P

en

l ne

an

i

a

C

ra

75°

r 40 y B 0m a n

k

Mt. Melbourne

M

Coulman Island

L 74°

Beaufort Island

R

i

78°

urdo McM d Soun

c

t

77°

m nk 400 Ba s os

Ross Is. Cape Crozier McMurdo Station

Ros s

Ic

V

Latitude (South)

a

so 40 n B 0m a n

k

73°

79° 160°

165°

170° Longitude (East)

175°

180°

100km North

R o s s

10 00 m

S e a

e

S h e lf

175°

Houtz Bank

es B ank

Cape Colbeck

Bay of Whales

Hay

450 m

450 m

170° Longitude (West)

165°

Figure F.1. The bathymetry of the Ross Sea.

160°

155°

Contents Foreword xi Preface C h a pt e r 1 C h a pt e r 2

xv

A Meeting with Emperor Penguins 1 The Kings of Saint Andrews Bay 7

C h a pt e r 3

The Seven Colonies of the Ross Sea

24

C h a pt e r 4

The Emperors of Cape Washington

39

C h a pt e r 5

Kings and Emperors in One Year The Commuter Journey

C h a pt e r 6

83

C h a pt e r 7

The Fledging Journey

95

C h a pt e r 8

The Pre-molt Journey

103

C h a pt e r 9

The Post-molt Journey

111

How Do They Do It?

123

C h a pt e r 1 0 C h a pt e r 11 C h a pt e r 1 2

Predator as Prey

61

142

Climate, Conservation, and Consumption Acknowledgments

167

Annotated Bibliography Index 181 Plates follow page 96.

171

157

Foreword

Hearing the stories of early Antarctic exploration and research, or of the origins of human spaceflight, I have at times felt I was born in the wrong era. There was so much to truly explore, so many things untouched, untested, unknown, and so many wonders yet to behold both on and off our planet. Although I would not have had the same opportunities to explore at that time as I have had throughout my career “on the ice” (the locals’ term for living and working in the Antarctic) and in space, I still fondly imagine those early days. Perhaps it all works out for a reason, with still-countless discoveries to be made by scientists of all backgrounds and genders, on Earth and beyond. The early decades of Antarctic research were truly a different time— more pure, wilder, with scientific processes and methods unmarred by countless safety constraints and limitations, rules and regulations. It was a time when true pioneers like Jerry Kooyman embarked on the frozen unknown of Antarctica, armed with only their burning scientific questions, and absolutely no one’s comparable experience to draw from. A time when sticks of dynamite were handed to willing scientists with no background in explosives (yes, this was one of Jerry’s exploits, even if it isn’t recounted in the pages to follow!), and by some grace you left the ice with not only your data but all your fingers and toes. There are striking similarities to this paradigm in the world of human space exploration, as we embarked on our initial journey to the moon in this same period. The NASA of today, burdened by the federal weight of bureaucracy and its required boards, meetings, and approval processes, would have been unrecognizable to the army of fresh young engineers making executive-level decisions on an hourly basis as we succeeded in meeting President John F. Kennedy’s bold proclamation of setting foot on the moon. Both in space and on the ice, it was a time of unbridled, raw exploration. Those that were fortunate enough to play a role made immense con-

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Fo r ewor d

tributions, blazing the trail for others to follow. Jerry was undoubtedly at the head of this pack. In addition to being a true explorer, he is a bona fide naturalist. His research and pursuits have not only sought answers for hypothesis-driven research but also served to unravel the natural-history mysteries of the organisms he has studied. In this book, Jerry recounts his tale of one of the most iconic examples of charismatic megafauna in a way that captures both the magnitude of his science and the elegant descriptions and personal anecdotes that transport the reader to the ice (all through the lens of a changing climate). His acts of veritable heroism—raging-river crossings, risky glacial traverses, frequent excursions on figurative and literal thin ice—were simply routine components of his daily scientific procedures. And although such operations were inconceivable during my time in Antarctica four decades later, one cannot deny that a share of the adventure has been lost along with those freedoms from regulation. Jerry is not only a scientist, naturalist, and explorer; he is also an inventor. To him, it seems a simple endeavor to whittle, tinker, or create something new out of thin air that will be used precisely for its intended “porpoise.” During his initial research, one could not just open a catalog of wildlife recorders to measure the parameters they are designed to study. When Jerry sought to reveal the impressive depths and durations of the consummate divers, his first step was to design and build his own recording system. I’ve yet to find a more creative use for a kitchen timer! And though he is a pioneer of many first achievements, Jerry would never bring this up himself, for he is among the most humble scientists of his caliber. “There are some who can live without wild things, and some who cannot.” Jerry opens chapter 1 of this book with this telling quote from Aldo Leopold. Like Jerry, from the time I was a young child I possessed a curiosity about the world around me, yearning to experience and understand more about the natural wonders of the planet. This scientific curiosity evolved into a theme of exploration that has guided and driven me throughout my life. Plunging under the Antarctic ice to research the diving physiology of emperor penguins was an academic endeavor inspired by original explorers and true galvanizers like Jerry. Continuing my work on animals in extreme environments eventually led to my ultimate career goal of conducting literal out-of-this-world science while gazing down on our home planet from up above. If you’ve picked up this book, my assumption is that you too are already someone who cannot live without wild things . . . My expectation is that Jerry’s stories will tie you even more deeply to that wild. The man, the myth, the legend—not just a casually blurted title but the actual words I use to define Jerry. Yet I’d be remiss if I didn’t add the term

Fo r ewo r d

›

xiii

mentor. The stimulating conversations, advice, and stories recounted to me by Jerry and the adventures we shared during my years studying at the Scripps Institution of Oceanography are among my most-cherished memories. They were pivotal in shaping my academic foundation and the course of my future trajectory, as is the case for countless others whose lives Jerry has graced. I commend Jerry—and Jim Mastro—for this latest pursuit in capturing his life’s adventures and communicating them with the world. Those of us fortunate enough to have led such a profound life, be it on or off this planet, understand that these adventures and experiences are not ours alone. We explore on behalf of all humanity, and thus it is our responsibility to relay our insights, to share them with all humankind, and if you’re lucky enough, to blaze as wide a trail as Jerry. Jessica Ulrika Meir, PhD Comparative physiologist and NASA astronaut

Preface

The emperor penguin was probably first seen in 1820, in loose pack ice somewhere north of the Ross Sea, by the Russian explorer Thaddeus von Bellingshausen during his circumnavigation of the Antarctic Continent. However, during British explorer James Cook’s second expedition (1772– 1775), when he was searching (unsuccessfully) for Terra Australis Incognita (the unknown southern land), the father-and-son German naturalists Johann Reinhold Forster and Johann Georg Adam Forster described a bird that may have been an emperor, thus their designation as Aptenodytes forsteri in Gray’s 1844 naming of the species. These remarkable birds have several unique characteristics that set them apart from all other penguins: (1) they are the largest penguin; (2) they are the only golden-breasted penguin; (3) they spend their entire life either in the sea or on sea ice; (4) they breed and incubate their eggs in the dead of winter (the Fjordland crested penguin does this, too, but under significantly less-harsh conditions); (5) males do all the incubation; (6) the male’s 120-day fast is the longest of any penguin, and perhaps of any bird; (7) at the highest latitudes, breeding and incubation are done entirely in the dark, without building a nest, while exposed to fierce Antarctic weather; (8) they are not territorial, and the males rely on huddling with each other to get through the long winter night; (9) when they walk as a group, they walk in single file; and (10) they are the only penguin that walks with its wings pressed against its sides instead of holding them out for balance. While their standing height is just under a meter in normal posture, they can extend their necks about another 10 centimeters to get a look above the crowd. Their massive feet provide a thermal barrier between their body’s hot core and the sea ice on which they stand. Indeed, those remarkable feet have many roles. The claws are the main propulsive grip when scooting along on their stomachs (a process called tobogganing), and their feet serve as a brake and rudder while swimming. They also function as a mobile nest for the egg and chick during incubation and brooding. Shielded

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Pr e fac e

by the feet from the life-threatening, intense cold of the ice and protected from the elements by the brood-pouch feathers, the egg or chick is maintained at about 38°C (100°F) while the air and ice temperature just one to three centimeters away can be −50°C (−58°F) or lower. When the penguins rock back on their heels, a small, thick, quarter-sized pad is the only skin touching the ice, and within this heel pad are air-filled cells that provide insulation for the blood circulating through the foot. In short, the emperor penguin is supremely adapted to its environment. And no wonder: penguins have been around since they diverged from loons in the late Cretaceous, and the emperor itself has been around for 2.5 million years, only slightly less than the Adélie penguin (Pygoscelis adeliae). I find it fascinating that the two oldest penguin species are also the only ones that breed so far south. Of course, even Adélies vacate the premises when winter arrives. The emperor males stay on, incubating eggs in bone-chilling temperatures, hurricane-force winds, and total darkness—the harshest of all possible physical conditions for any higher vertebrate. It is therefore not surprising that the first breeding location for such a large, beautiful, and abundant animal wasn’t discovered until 1902, by members of Robert Falcon Scott’s 1901–1904 Discovery Expedition. The colony was at Cape Crozier, on the opposite side of the island from Scott’s base at Winter Quarters Bay. During Scott’s subsequent 1910–1913 Terra Nova Expedition, three members of his crew—Edward A. Wilson, Apsley Cherry-Garrard, and Henry R. “Birdie” Bowers—made the winter journey from their base at Cape Evans (on the western coast of Ross Island) to Cape Crozier in order to collect eggs for a scientific study on embryology. Cherry-Garrard chronicled that trip in his book The Worst Journey in the World. And indeed it was. The three men braved brutal temperatures, privation, and extreme discomfort—literally skating on the edge of death—in conditions the penguins endure routinely. The fact that the penguins can do this and questions about how they do it have been the focus of multiple scientific studies. Members of Scott’s Discovery Expedition were the first to realize the birds were incubating eggs during the winter, but the first scientific research on this behavior didn’t take place until a man named Bernard Stonehouse conducted studies at Dion Islands (incidentally the most northerly of emperor penguin colonies) during the winters of 1948 and 1949. He was followed by the French biologist Jean Prévost, who in 1952 began his study of emperors at the Pointe Géologie colony, just a few hundred meters from what was later to become the French research base Dumont d’Urville.

Pr e fac e

›

xvii

Stonehouse’s study was the more heroic of the two early works, and perhaps the most physically challenging of any study on penguins. He was originally in the Antarctic as a copilot for the British Antarctic Survey (BAS) at Stonington Island, but a plane crash and total destruction of the aircraft put an end to that. After several days, he and the pilot were spotted and rescued by a reconnaissance plane from the Ronne Antarctic Research Expedition of 1947–1948. Following their rescue (which I heard about decades later from Finn Ronne’s wife, Edith), Stonehouse and three companions made a short visit to the Dion Islands by dogsled, in October. He was forced to withdraw soon after to the Stonington Island base, because of deteriorating ice. I imagine he thought it would have been too embarrassing if the Americans had to rescue him again, especially since there was a bit of rivalry between the BAS and Ronne expeditions at the time. However, he was intrigued by the birds and was determined to study them. His only choice was to do the work in the winter, when the sea ice was secure. So in June he and two companions once again dogsledded back to the colony and remained until mid-August. And that is what is defined as a hardcore polar expedition. At the time of his study, only two other emperor penguin colonies were known: the one at Cape Crozier and another at Haswell Island, which was discovered by members of Douglas Mawson’s Australasian Antarctic Expedition of 1911–1914. The colony at Pointe Géologie was discovered in 1950, and by the time Prévost had published his description of emperor breeding behavior in 1961 (coincidentally, the same year as my first trip to Antarctica), eight more colonies had been discovered, including one at Coulman Island, in the Ross Sea. (I learned about this colony later in my 1961 trip but never dreamed that one day I would visit it in the course of my research.) Prévost’s work was the start of the longest-term and most productive ecological, behavioral, and physiological emperor penguin research program, but it ended abruptly in 2008, when the French government imposed restrictions on handling the birds. There have been, of course, numerous other studies of emperor penguin breeding behavior and physiology in the years since Stonehouse and Prévost conducted theirs, and what the emperor males do during the winter is now well established. But what about the rest of the year? As crucial as successful egg incubation is to emperor penguin survival, there is much more to their story. In my research, I have found that their lives are marked by four critical journeys: the chick-feeding (“commuter”) journey, the fledging journey, the pre-molt journey, and the post-molt journey.

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Pr e fac e

This book is about those journeys, the hazards the penguins face during each one, and the physiological adaptations that allow them to not only survive but thrive in the harshest and most physiologically challenging environment on Earth. It is also the story of my life and research with emperor penguins, my quest to define the natural history of their annual cycle, my adventures along the way, and my collaboration with many friends, including my two sons, all of whom I have had the privilege of working with on the ice of the Ross Sea. At several points in the book, I have indicated the availability of a

™ video clip showing the behavior described in the text by including

the symbol shown here. You can find and watch these videos by visiting the book’s web page, at https://press.uchicago.edu/sites/kooyman-mastro/ index.html.

Breeding Emperor penguins begin to arrive at their colonies from about mid-March until about mid-April. At Pointe Géologie, where the arrival can be observed from the station, the largest influx occurs from March 30 to April 13. At the end of their long march over 50 to 100 kilometers of sea ice, the birds form a long, thin line, each penguin a uniform distance from the others. At the Ross Sea colonies, where our studies were conducted, this arrival has never been witnessed. Upon arrival, the males may weigh as much as 45 kilograms, with an average weight of 37 kilograms. The females range up to 32 kilograms, with an average weight of 28 kilograms. This sexual dimorphism has little or nothing to do with male dominance; there is no territorial defense or control of females, though there may be sexual selection by the females. The male needs a large fat store for the long winter fast to which he is committed, and the females may prefer the more robust males. Over the next month, the birds engage in prenuptial behavior and bonding, culminating in the first copulations a month after arrival. Based on data from a few banded birds, few pairs reunite the following year. Egg laying begins about the first week of May and continues through the first week of June, the exact timing depending on the latitude of the colony. Within twenty-four hours, the female passes the egg to the male and departs the colony to hunt for food over the next two months. The male incubates the egg through the winter, until the female returns to take over in early August (about the time the egg hatches) and the male goes to sea for about three weeks to feed. After that, both members of the pair take turns nurturing the chick and feeding at sea,

Pr e fac e

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xix

Figure P.1. The annual cycle of the emperor penguin. F = fledging (the arrow denotes the approximate duration); M = molt; PM = post-molt travel; B = arrival at the colony and bonding or mate selection; L = egg laying; Pause = the short time that the female may delay departing because of hesitancy to give up the egg and/or the time after the male assumes incubation and the female delays leaving; I = incubation, largely by the male, including the time the female remains nearby before leaving on the postlay trek, as well as the rest of the time until hatching; Post-Lay Trek = the travel of the female after leaving the colony (this has been determined only by the Australians at Taylor Glacier and Amanda Bay, and possibly at Pointe Géologie); H = Hatching and transfer of the hatchling to the female; B = Brooding, the male broods briefly until the female returns from her trek and assumes the task, then brooding alternates between the male and female through October, with each session of variable duration, depending on the foraging success of each adult; C = crèche (during late September the chicks form crèches, and this continues into November). During both October and November, depending on the weather, both brooding and forming crèches will occur.

with their feeding trips getting progressively shorter until the chicks are ready to fledge. Figure P.1 is a graphic representation of the emperor penguin’s annual cycle. The periods of occurrence and durations are based on my estimates from Cape Washington. They will vary somewhat depending on colony location, especially latitude, as well as on the weather and sea ice conditions in any given year.

Table 0.1. Metric and imperial conversions Centimeters

Inches

1

0.39

5

1.97

10

3.93

20

7.87

30

11.81

50

19.68

100

39.37

xx

Meters

1

Feet

3.28

‹

Pr e fac e

Feet

Meters

1

0.30

5

16.4

5

1.52

10

32.8

10

3.05

50

164

50

15.24

100

328

100

30.48

150

492

150

45.72

200

656

200

60.96

250

820

250

76.2

300

984

300

91.44

350

1148

350

106.68

400

1312

400

121.92

450

1476

450

137.16

500

1640

500

152.4

1000

3280

1000

304.8

Kilometers

Miles

1

0.62

5

3.11

10

6.21

20

12.42

50

31.07

100

62.14

200

124.27

250

155.34

300

186.41

400

248.55

500

310.69

1,000

621.37

1500

932.06

2,000

1,242.74

Pr e fac e

2,500

1,553.43

3,000

1,864.11

150,000 square kilometers

57,915 square miles

Grams

Ounces

5

0.18

10

0.35

20

0.71

30

1.06

40

1.41

50

1.76

100

3.53

150

5.29

200

7.05

250

8.82

300

10.58

350

12.35

400

14.11

450

15.87

500

17.64

Kilograms

Pounds

1

2.2

2

4.4

3

6.6

4

8.8

5

11.0

10

22.0

15

33.1

20

44.1

25

55.1

30

66.1

›

xxi

xxii

35

77.2

40

88.2

45

99.2

50

110.2

100

220.5

200

440.9

300

661.4

400

881.8

500

1,102.3

1,000

2,204.6

2,000

4,409.2

3,000

6,613.9

5,000

11,023.1

8,000

17,637.0

10,000

22,046.2

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Pr e fac e

[ Ch a pter 1 ]

A Meeting with Emperor Penguins

There are some who can live without wild things, and some who cannot. A l d o Leopo ld

Great Scott, what have I gotten myself into this time? It was early October 1961, and I was on my first excursion away from McMurdo Station, Antarctica. It seemed as though I was at the frozen edge of the world. The temperature was −30°C (−22°F), and the wind was howling at 60 kilometers per hour. To say I was uncomfortable hardly begins to describe it. Sir Douglas Mawson, the Australian explorer, once said of Antarctica: “We had discovered an accursed country. We had found the Home of the Blizzard.” I suppose I couldn’t reasonably compare my situation to the suffering that Mawson experienced. Still, the moisture in my nose was forming ice crystals—a new experience for a young man raised in Southern California who had never made a trip to the snow. Antarctica is the ultimate snow trip, though, so despite my discomfort, I was loving every minute of it. I was at Cape Royds, on the western side of Ross Island, at the southwestern corner of the Ross Sea. In front of me was McMurdo Sound, the southernmost open body of water in the world (for part of the year). It is bordered by Ross Island on the east, the Antarctic Continent on the west, and the McMurdo Ice Shelf on the south. Behind me loomed 4,000-meter Mount Erebus, one of the tallest mountains in Antarctica and one of the few active volcanoes in the world with an open lava pool. Strong winds called katabatics were sweeping down from the mountain, as they often did, and hammering the sea ice in front of me. With my back to the wind, I was captivated by the result. The horizon was the most crystal clear I had ever seen, especially having been raised in the perpetual haze of the Los Angeles Basin. The shallow bluffs of the cape, on which I was standing, created a windbreak that

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C h a pt e r 1

Katabatic Winds Katabatic winds (also called downslope winds or gravity winds) are caused by air flowing down from higher to lower altitudes. They usually occur when the air in contact with a mountain range or a polar plateau becomes colder than both the air at the same altitude around it and the air below it. Because air becomes denser as it gets colder, it flows downward under the force of gravity. These winds occur frequently in the polar regions and can reach speeds of up to 300 kilometers per hour.

allowed thin ice to form near the shore, while the ice farther offshore was ripped apart and pushed to the north, leaving a small area of open water. I was marveling at this spectacle when my attention was captured by an unbelievable apparition. Three amazing creatures blasted through the thin ice not far away and began sliding on their bellies toward me. Though this was the first time I had seen emperor penguins, I knew exactly what they were. Their wet feathers glistened in the low sunshine as they stopped sliding, rose to their feet, and began walking toward me. At an impressive one meter tall and about 30 kilograms in weight, they are by far the largest of all diving birds (plate 1). I would have been awestruck even if they had waddled across the ice with their wings outstretched like an Adélie penguin, but emperors walk with the stately pace of royalty, with their wings flattened against their sides and their upper bodies swaying slightly from side to side. Their backs were black, which contrasted with the golden hue of their breasts. Feathers extended to the tops of their dinosaurian feet. Watching them, I thought if I froze to death before the day was over, I would cross the veil a happy man. On this, my first trip to Antarctica, I had come to McMurdo Station to work as a technical assistant for Professor Donald “Curly” Wohlschlag of Stanford University, whose research focused on cold adaptation in Antarctic fish. Except for the raw beauty around me and the penguins that stood a short distance away, I knew little about this strange and wonderful land. Over time, I came to understand that the Ross Sea is truly one of Earth’s unsung treasures. It is the last large, almost unexploited body of water on the planet. Until about 1997, no legal fisherman’s net or longline had ever sullied these waters. No oil explorers have ever drilled here. No oil tanker has ever soiled the sea and ice of this place with its cargo (except, unfortunately, near McMurdo Station). This lack of environmental damage is due largely to a climate that is hostile to both humans and the machines that

A Meeting w ith Emperor Pengu ins

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3

help them explore, exploit, and settle. The environment is also not suitable for most other species of birds and mammals. Of the approximately 10,000 species of birds and 5,400 species of mammals on this planet, only two have made Antarctica their year-round home: the Weddell seal (Leptonychotes weddellii) and the emperor penguin. I resolved to learn more about them. Of course, as I stood watching those three emperors in front of me, amazed at their apparent comfort in that bitter cold, all of that was ahead of me. The weather had begun deteriorating and the cold was brutal, so my two companions and I requested an early pick-up. Worried that we might freeze to death before the helicopter arrived, we decided to hike across the cape to take shelter in the hut left by Ernest Shackleton’s 1907–1909 British Antarctic Expedition. I wondered if doing so was legal, but my companions were both overwintering Antarctic veterans, so I assumed they knew what they were doing. Once inside this historic building, I continued to ponder questions about emperor penguins and Weddell seals. Apart from the two breeding studies on emperors, little was known about either in 1961, and I was intrigued by their ability to not only survive but thrive in such a harsh and unforgiving environment. The sound of an arriving helicopter ended my reverie. We ducked under the spinning rotor and scrambled aboard, and during the thirty-minute flight back to McMurdo Station, I watched the desolate scenery pass by. Not a tree, bush, or blade of grass in sight, yet I had just seen one of the most magnificent animals on the planet. Later in my five-month stay at McMurdo, I made other sojourns across the sea ice and to Cape Crozier and Cape Royds, and I saw the other common inhabitants of McMurdo Sound: Adélie penguins, leopard seals, crabeater seals, orcas, and an occasional minke whale. If I didn’t realize it then, it became abundantly clear before long: Antarctica had hooked me. It was the Weddell seal that had first captured my imagination. On one of my first forays onto the frozen sea, I was able to walk right up to one lounging on the ice and was astounded that it remained undisturbed (figure 1.1). I had been casting around for a good PhD project, and this seemed a perfect opportunity. It was a diving animal that was easily accessible and obviously tractable, and no one was working on their diving physiology. I followed up on that plan when I left Antarctica several months later. A series of fortunate circumstances found me back at McMurdo Station in 1963, as the principal investigator (and lone participant) in my own PhD research project on Weddell seals. Up to that point, there had never been a way to reliably determine what marine mammals were doing once they went underwater. How deep could they dive? How long could they hold

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Figure 1.1. A Weddell seal mother with her pup on the sea ice of McMurdo Sound. (Photo by J. Mastro.)

their breath? Their behavior underwater was what scientists call a “black box.” What was in it was unknowable. Researchers had force-dived seals in pressure chambers to determine their breath-hold capacity, but that type of information was only minimally useful in determining their natural behavior. To solve this problem, I invented the first time/depth recorder (TDR). With the help of a Tucson, Arizona watchmaker, I cobbled together a kitchen timer, a Bourdon tube (a tube that changes shape depending on pressure), and a glass disk smeared with a thin layer of grease and dusted with fine charcoal, all encased in a thick brass canister. It was crude and it was heavy, but it worked. I attached the TDRs to Weddell seals and for the first time obtained records of their underwater behavior. It is difficult to overstate my excitement when I opened the first recovered TDR and saw that dive trace on the disk. Unfortunately, the kitchen timers ran for just an hour, so though it might take me days to recover a TDR, all I could see was what the seal did in that first hour. I also used capillary recorders, which are thin glass tubes that are closed at one end and dusted on the inside with a water-soluble dye. When the tube was submerged, a ring would be left at the point of maximum compression. By measuring the distance to this ring from the open

A Meeting w ith Emperor Pengu ins

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end of the tube, it was a simple calculation to determine the depth to which it had been exposed. The tubes were small, light, and inexpensive, but they could record only the deepest dive of however many dives the animal had made before I could recover them. There was a lot riding on that first field research project, including my future in graduate school. The questions were many. Would my sealcapture techniques work as planned? Would I be able to attach and recover the TDRs and capillary tubes successfully? Would they work in the field as they were supposed to? The answers were mostly yes, but there were still bugs that needed to be worked out. (Case in point: I ultimately lost three of the five recorders I had with me that year.) I returned the following season with more TDRs and capillary tubes, a more refined method for capturing the seals and making sure I could get my recorders back, and another graduate student to assist me. That year I recorded (separately) the deepest dive (600 meters) and longest breath hold (forty-six minutes) then known for a pinniped (seals, sea lions, fur seals, and walruses). Though emperor penguins were never very far from my mind, for the next couple of decades my main objective in the Antarctic was to study Weddell seals. In 1974, now with my own laboratory at the Scripps Institution of Oceanography (SIO) in La Jolla, California, I worked with a brilliant and talented, if eccentric, engineer to develop a much more sophisticated TDR. This one was shaped like a torpedo and could record dive data for two weeks, giving me unparalleled insight into the lives, foraging habits, and physiology of marine mammals. I spent the next eleven years taking advantage of that, deploying the TDRs on several seal and sea lion species around the world, including Weddell seals, and even on leatherback turtles. Unfortunately, those mechanical TDRs were still too big for emperor penguins, and the technology didn’t yet exist to make them smaller. By the early 1980s, though, electronic technology had progressed to the point that my hopes were rekindled. I set one of my lab technicians to work building small electronic instruments that wouldn’t impede the penguins’ ability to swim and forage. Deploying them on emperors, however, would still be logistically difficult; I hadn’t yet figured out which of the Ross Sea colonies would be the best study site, nor had I yet sorted out the logistics and feasibility of a deep-field research camp on annual sea ice to study emperor penguin diving behavior. Plus, my new devices were untested in the field. To convince the National Science Foundation (NSF) (the government agency that funded much of my research) to support an emperor penguin project, I needed to have everything mission ready. I decided the best course of action would be to deploy the new record-

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ers first on the emperor’s cousin, the king penguin (Aptenodytes patagonicus). This presented three distinct advantages: (1) accessing a king penguin colony, although still logistically challenging, was easier and less expensive than accessing an emperor colony; (2) studying kings would allow me to compare the behavior and physiology of the two similarly sized birds that nonetheless operated in very different biomes; and (3) testing my devices in this way would give me the opportunity to iron out any problems that might arise without jeopardizing my plan to establish an emperor study. In 1985, I made the connections necessary to get myself and an assistant to a king penguin colony on a remote sub-Antarctic island. My dream of conducting a comparative study of the two diving birds was about to become a reality. It was a significant career change from my work on marine mammals, and I never looked back.

[ Ch a pter 2 ]

The Kings of Saint Andrews Bay

Knowing natural history allows an investigator to phrase questions with precision. It facilitates synthesis from lower to higher levels of integration. Geo rge A . Ba rt ho lo mew

Sometimes what seems like a good idea doesn’t seem so good upon execution. That was exactly what I was thinking as I looked at the checkerboard of whitecaps that lay between us and the beach where we were supposed to land. It was February 7, 1985, and I was about to embark on a first-of-itskind field study of king penguin foraging behavior and physiology, if only the weather would allow it. My field assistant, Phil Thorson, and I were aboard the Antarctic cruise ship World Discoverer, where we had served as both honored guests and lowly boat drivers. I was fine with that arrangement. Giving lectures and ferrying passengers to shore at each stop along the Antarctic Peninsula was a small price to pay for passage to my study site on South Georgia, a wild and mountainous island deep in the South Atlantic. We had arrived there that morning in perfect weather. Instead of taking us directly to Saint Andrews Bay, the site I had selected for my project, the captain, to my dismay, decided to stop at Royal Bay so his passengers could roam the perimeter of the king penguin colony there. In my experience, weather usually worsens at South Georgia later in the day, and every hour we spent shepherding passengers at Royal Bay jeopardized our chances of making a successful landing at Saint Andrews Bay (figure 2.1). By the time we reached Saint Andrews Bay, my fears were realized. The weather had turned sour. Katabatic winds were roaring down from the jagged mountains that form the island’s spine, and a heavy swell was rolling in from the south. The captain made it clear he was opposed to putting us ashore in these conditions. It was beginning to look like months of planning and effort were about to be thwarted.

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Figure 2.1 The location of South Georgia Island and Saint Andrews Bay, with bathymetric readings. (Modified from Kooyman, Cherel, et al., “Diving Behavior and Energetics.”)

However, after some gentle arm-twisting from retired NSF program manager George Llano, Hubbs–SeaWorld Research Institute director Bill Evans, and SeaWorld curator of birds Frank Todd, the captain relented. The three were well-respected marine scientists and frequent Antarctic expedition leaders, and their arguments were convincing. Both the NSF Office of Polar Programs (NSF/OPP) and the British Antarctic Survey (BAS) had a lot of money and prestige riding on my project, and this was the only chance we would get. Because of the ship’s schedule and my other commitments, if we weren’t put ashore that day, the project was dead. As we motored away in two Zodiac inflatable boats heavily laden with all the food, equipment, and survival gear we would need for several weeks of isolation, I looked up at the ship. There must have been a hundred tourists

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in red parkas lined up along the rail, smiling and waving as they watched us leave. Phil and I waved back. We had shared dinners and stories with many of them, and we would never see them again—unless we failed to make this landing. Once we left the protection of the ship, the wind hit us with full force, and I really began to wonder if this was going to work. Each boat had an operator and an assistant, and they were all clearly anxious to get this over with. They drove us as fast as they could for the shore, right into the wind. We had piled our gear forward to help keep the bow down, but we were still bouncing hard on the choppy water. I was up forward as well, hanging on to the boat safety straps and trying to protect our gear—and me—from flying out. Phil was doing the same in his boat, and we were both getting drenched with salt spray. It was like driving through a heavy rain with no windshield. Once we got close to the island, we made a pass by the landing beach, but the breakers pounding the shore were three meters high, with another three meters of spray blowing off the crest. It would have been suicide to land there. Where to go? I spotted a rocky promontory at the north end of the bay that looked like it might provide protection from the swell. I pointed to it enthusiastically before anyone got a rash idea about surfing the break to the beach. My boat operator spotted a sandbar free of breakers and aimed for it. Just before we hit the shore, his assistant jumped out to help in the landing. Bad idea. The freezing water was still over a meter deep. The assistant vaulted back into the boat, but not before filling his waders and rain slicker up to his chest. The driver used the boat’s motor to push us onto the bar. The assistant jumped out again, and I followed. We dragged the boat farther up the beach and hurriedly begin offloading boxes and bags of equipment. By this time, Phil had arrived in the second boat. When the last bag was on the beach, I turned to thank my boat crew, but they were already racing back to the ship, with Phil’s boat right behind them. It was such a fast dropoff that I looked around, half expecting not to see Phil. We took a moment to congratulate ourselves for making it here and regretted it immediately. A big swell pushed up on the beach, swamping all our gear and threatening to pull most of it out to sea. Our research project, not to mention our lives, depended on that equipment! We scrambled madly through the wash to retrieve it, running as best as we could in sand so soft that with every step we were down to our boot tops. It felt as though we were struggling through molasses. The next few minutes seemed like hours as we pushed, pulled, dragged, and carried bags and boxes up the beach, across a small lagoon, and around

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Figure 2.2. Elephant seals on the beach at Saint Andrews Bay.

snorting elephant seals. Those massive pinnipeds formed a living, sausagelike wall between us and dry land, and our job was complicated by having to weave between them (figure 2.2). It did not help that we were also pushing into that brisk and bitterly cold katabatic wind that stunned our faces and made our eyes water. Finally, everything was rescued, and we dropped to the ground, utterly exhausted. For a moment, I wondered if this was what cardiac arrest felt like. But despite the pain in my lungs and muscles, this was a cherished moment. My first project to explore the mysteries of the Aptenodytes, the world’s largest penguins, had begun! After we had regained our breath, and with our gear now safe, we gathered up just what we needed for the night and trudged a kilometer inland to the small hut that BAS had built there in 1980. Small indeed. Its eight by twelve feet were divided into a kitchen/bedroom, with two bunks against one wall, and a small cooking shelf on the other wall; a food storage room; and an entry room with a generator, tools, penguin capturing devices, and other equipment. After struggling without success to start the single-burner Primus stove, Phil and I shared a cold and tasteless dinner of cheese and sledging biscuits. (It was a stark contrast to our last meal aboard the World Discoverer, which included escargot, frog

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legs, and cordon bleu.) Then, utterly fatigued, we rolled out our sleeping bags on the bunks and collapsed. Even though I felt dead on my feet, I couldn’t help reflecting on what had come to pass since sailing from Argentina two weeks ago. We were on the World Discoverer because it was the only way to get to South Georgia conveniently, and because Evans, Llano, and Todd had been instrumental in arranging our passage. The ship’s itinerary took us first to the Antarctic Peninsula, where we stopped at several historically and biologically significant locations. I had long been fascinated by the history of Antarctic exploration, so it was thrilling to see some of the places I had read about and visit the crumbling ruins left by heroic age explorers. One of our first stops was at Paulet Island, where there was a large Adélie penguin colony, and where I had my first experience as a boat operator. I was surprised (and shocked) that the method for launching the Zodiacs was to lower the boat from the upper deck into the water—with the driver (me!) inside, sans life vest. I did not like this. We also visited Poland’s Arctowski Station on King George Island, a stone’s throw from where a fellow NSF-supported biologist was running a twenty-year study of Adélie, chinstrap, and gentoo penguins. We passed close by Point Wild, Elephant Island, from where Ernest Shackleton and five companions sailed in a lifeboat for South Georgia Island in 1916, after his ship Endurance had been crushed by ice. It is hard to imagine how uncomfortable they must have been as we pressed on with the tourists in our luxury cruise liner. Because Phil and I were going to leave the ship near the end of the cruise to conduct a scientific study on South Georgia, we were treated like special guests. This was especially noticeable at dinner, when the tourists all angled for a chance to eat with us. One evening, I dined with a woman from Palos Verdes, California, near where I was raised. She told me her father designed the famous P-51 Mustang, a World War II fighter plane. Since I am keenly interested in airplanes, this was one of my more memorable evenings on board the ship. Now I lay on my bunk, listening to rain squalls pound the roof while the wind tried to remove it. It must have been blowing 70 knots, and the hut was pulsating. Even though BAS had filled large drums with rocks and attached them to thick cables strung over the top of the hut, I wondered if the cables were going to hold. The deafening roar was like a train barreling through the building. It was only because Phil and I were exhausted that we were able to sleep at all that first night. We were awakened the next morning by the sounds of the wild. Ele-

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phant seals snorted and razzed, and king penguins trumpeted to each other. It was a far cry from the ubiquitous grumble of the Discoverer’s engines and an even further cry from traffic, airplanes, telephones, and the other sounds of civilization. Phil and I threw on our parkas and boots and headed outside. The sun was just clearing the horizon, giving the glacier-capped peaks a stunning alpenglow. In the green grassy meadow near the hut, reindeer grazed. We might as well have been in Switzerland, except for the jostling elephant seals, growling Antarctic fur seals, king penguins wandering the beach, and albatrosses soaring overhead. Phil and I began the onerous task of moving all the gear from the beach to our camp. A kilometer doesn’t sound like far, but it’s a long way to manhaul heavy boxes, and the work was exhausting. During our rest breaks we assessed our little building, the food and fuel cache, and the supplementary equipment. The hut seemed to be none the worse for wear after the previous night, and I appreciated the skill and wisdom of the builders. It was lucky that we didn’t have to work from a tent camp, as our tents would have been shredded. We were actually the second group of guests to use the hut. In 1982, two photographers had stayed there for six months. Their idyllic life of photographing all the wonderful wildlife was interrupted when their temporary home became a refugee camp. After the British base at Grytviken (a former whaling station) came under attack by Argentina during the short but vicious Falklands War, three scientists from the nearby BAS research station at King Edward Point escaped to stay at Saint Andrews Bay until they were picked up by the Royal Navy. It was hard to imagine five people crammed into that tiny hut that barely held just Phil and me. Once we had stowed our gear, we were anxious to get started on our work. Our camp was about three kilometers from the penguin colony, which was on the opposite side of the bay. It was not a particularly long walk, but nothing is easy in the wild, and Saint Andrews Bay was no exception. On our first foray straight across the beach to the colony, skirting sleeping elephant seals along the way, we found that we had three rivers to cross, and one of them was the largest on South Georgia. In the warmest part of the day, with maximum solar radiation melting the Cook and Heaney Glaciers, the rivers were raging. I had waders and so managed to stay dry, but the boots Phil had been issued were short topped, and they filled with freezing water. Every time we crossed after that, Phil brought extra boots and socks so he could change into dry footwear on the other side. I thought about waiting for evening when it was cooler and the rivers were lower to make our crossings, but that was the birds’ quiet time. Not

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Figure 2.3. Overlooking Saint Andrews Bay, with a beach full of king penguins and jousting elephant seals.

only would our intrusion disturb them, but it would be too dark for us to find our experimental birds or conduct our work. It is hard to express the wonder we felt on our first visit to the colony. It was a sea of penguins! Forty thousand or more of them—colorful adults and fuzzy brown chicks alike—spread out before us in a raucous celebration of wildlife in one of the most scenically spectacular places imaginable (figure 2.3). The sound of tens of thousands of adults trumpeting and thousands of chicks peeping was almost deafening. And then, of course, there was the overpowering smell of penguin guano, mixed in with the pungent, fishy odor of elephant seal dung, wafting in from penguin-free areas of beach. A king penguin colony is a chaotic place, with birds always in motion. The adult pairs that had left chicks behind for the winter are greeted by extremely hungry offspring who need large meals before they fledge. While those parents set up a cycle of coming and going to feed their chick, other penguins are in search of mates and sex. For them, there is much displaying, head waggling, trumpeting, and neck stretching. This latter is an arcing maneuver that brings the head over and down the neck of the other. This famous image has been published many times and charms people by the apparent expression of undying love between the

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two birds. It is not an accurate interpretation. For one thing, only 30% of breeding king penguins seek the same mate from year to year. For another, the male uses this “necking” behavior to encourage the female to go down on her belly so he can mount her. Love has nothing to do with it. In addition, all this time there is often a third party involved: another male trying to horn in on the activity. The result is a lot of aggressive bill thrusts and wing wallops across chests and backs—hardly a romantic scene. Still, the whole activity is accomplished with such stately aplomb that it is as entertaining as clowns in a vaudeville act. King penguin breeding behavior is unique among penguins. It takes each pair about eleven months to fledge their single chick. Because it is such a long time, it is like a “hedge fund” among penguins: if you fail early, you can try again before the winter famine. It is also like a hedge fund in that the risks are great, and few from the second effort succeed. Also, unlike other penguins that all lay eggs, nurture chicks, and fledge on the same schedule, kings have a staggered breeding cycle. Some pairs molt in the Southern Hemisphere spring (late September to late October), feed for a month to regain lost weight, then move on to a ten-day courtship, laying their eggs by mid-December. The male assumes the first seventeenday incubation. After that, the pair alternate over the total of fifty-four days of incubation. Most of the eggs hatch by early February (midsummer), and for the next thirty days the chick is brooded. Then it enters the crèche stage, during which the parents try to fatten it up before all the adults abandon the colony for the winter. Other pairs finish their molt by mid-December and proceed into courtship and egg laying in February and March. These late breeders are almost certain to fail because the chicks will not be large enough to withstand the four-month winter fast (May through August). It is one of the longest fasts for any bird, and certainly the longest for a chick. During this fast, the king penguin chicks will lose about half their body weight. If they make it until the parents return in September, and if they are fed effectively after that, the older chicks will fledge by December. The system is hardly foolproof; overall breeding success from egg laying to fledging is only 31%. When the chicks do fledge, they face a gauntlet of predators. Giant petrels wait along the beach and just beyond the surf zone. Offshore may be a few leopard seals, if the colony is large enough to be profitable for them. Occasionally, killer whales will cruise through on their patrol for young elephant seals. For them, a bird snack will do in a pinch. In recent years, even fur seals have begun to prey on king penguins.

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Fledging The term fledging refers to when a bird’s flight feathers reach a sufficient length for it to leave the nest and fly. In the case of penguins, fledging is when the chick’s down feathers are replaced by waterproof adult plumage, allowing it to leave the colony and go to sea.

For a month after the chicks fledge, the adults forage to fatten themselves and then enter the molt. By this time summer is upon them, and warm, windless days can be hot enough to cause the birds to pant. The molt is total, with every feather replaced. It is a major weight-loss program, and after twenty-two to thirty-one days the birds have a beautiful new coat of feathers—at the expense of 50% of their body mass. More trips to sea bring their weight back to a level where sex becomes the major objective again. At this point, they begin strutting their stuff, following each other around, performing the pairing “dance,” and walloping any third party trying to horn in. Our early February arrival at the colony put us in the middle of hatching for the early breeders and laying for the late breeders. The early breeders— the lucky ones—had staked out the prime nesting spots. The only problem was, in order to reach their mate incubating the egg or brooding the chick, they had to negotiate an extended gauntlet of neighbors wielding daggerlike bills, which they jabbed at any intruder trespassing on their one-meterdiameter space. We found we could estimate the distance to the nest for any bird by the number of ruffled feathers from stabs in the back or chest from birds defending their domain. Those late breeders had a different and more serious problem: finding a free place to lay their egg. Most of the best nesting landscape had been occupied before they arrived, so they often had to settle for a place on the bank of the river or near the beach. Like homes and habitats everywhere, there are risks associated with building on a riverbank or oceanfront, and in the penguins’ case, it often ended in disaster. The thaw of the glaciers was at full flood at this point, and the river was roaring in the heat of the day. When the rising river eroded and widened the streambed, as it often did, nest sites on the bluff collapsed into the river like houses along the Mississippi River. Beach property was no better. High surf often strikes during spring tides, and nest sites there are flooded by large waves pounding the shore-

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Figure 2.4. Breeding king penguins at Saint Andrews Bay.

line. On our hikes to and from the colony we often saw lost eggs lining the shoreline, casualties of the river and the surf. On February 28, about halfway through our time at Saint Andrews, Phil and I collected a lost, fresh egg being bathed in icy glacier water and cooked it for dinner as a midseason celebration. Scrambled up, it filled the entire frying pan. King penguin eggs are large, and they have much more albumin than a chicken egg. Nonetheless, it did not taste fishy and passed the Saint Andrews Bay cuisine standard. (We also had our last two Cokes and a dessert of Swiss chocolate, which George Llano had sequestered in our bags just before our departure, bless his soul. But we never had another penguin egg.) When we began this project, little was known about king penguin habits at sea. Bernard Stonehouse, whom I mentioned in the preface for his study of emperor penguins, had gone on to study kings in 1953 (the results of which he published in 1960), but he had reported only on land behavior and ecology, and the duration of their foraging trips. That was it! As usual, once the birds disappeared into the water, their activities were a complete mystery. That huge unknown was what brought me here. My goals, modeled after my work with Weddell seals and other pinnipeds, were to get answers to the following: What types of dives do they

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make? Is there pattern to them, depending on the prey type? How long and deep are the various dives? What is the preferred time of day to feed? What is the deepest dive we will record? So many questions and so little time. At Cape Crozier in 1969 I had measured a few emperor penguin dives using capillary tubes. One of them had a maximum depth of 265 meters, and as of February 1985 that was still the record for any diving bird. However, my sample size had been small. I was sure the birds were capable of more and that a larger sample size would reveal a dive to exceed that record. But what about king penguins? In 1980, while studying the diving behavior of Antarctic fur seals on Bird Island (a small island near the northwest tip of South Georgia), I had hoped to attach newly developed histogram recorders to king penguins. These electronic devices, which weighed only about 35 grams apiece, logged each dive by sequestering it into one of several “bins” of a specific depth range, such as 0 to 20 meters, 21 to 40 meters, and so on, with the maximum depth as a number. Unfortunately, there were no breeding kings on Bird Island, but a fortunate circumstance allowed my graduate student and two BAS technicians to cross over to Schlieper Bay on South Georgia and attach instruments to king penguins there. Those instruments measured two dives greater than 240 meters. It had been enough to whet my appetite, and as a result Phil and I were now committed to do this project at Saint Andrews Bay. Oh, happy day, and what a lucky break! Phil and I had discovered that Saint Andrews Bay was one of the best-kept secrets of South Georgia Island, and perhaps of the entire sub-Antarctic. It had exceptional scenery, lots of wildlife, and (except for our first day) generally mild weather. My four-part project was fairly straightforward: (1) collect stomach samples for food-habit analysis, (2) place histogram recorders on birds for diving analysis, (3) attach speed recorders on other birds for swim-speed analysis, and (4) measure metabolic rates. We deployed most of the recorders early to increase our chances of recovery before the BAS ship was scheduled to pick us up. These were the same devices that my graduate student had used at Schlieper Bay, making this only the second time a multiple-depth recorder had been deployed on a diving bird. (Although they were the best technology that existed at the time, they were primitive by today’s standards, and the data they provided turned out to be not very useful. Unfortunately, this did not become clear until after I was able to download and analyze the data in my laboratory at Scripps).

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All the birds with instruments attached had to be recaptured when they returned to the colony so we could retrieve the instrument. The only reliable way to find a particular bird in a colony of approximately forty thousand adults was to attach VHF radio transmitters and then use a directional antenna to find the location of the pulsing transmitter. It worked well, and it was satisfying to find a bird we had released one to two weeks earlier. The stomach lavages (forced vomiting) were messy and unpleasant— more for the bird than for us, no doubt—but they were necessary to determine the birds’ prey selection. In order to develop a fuller picture of penguin foraging behavior, we had to know what they were eating. It turned out, from this study and from later studies, that their primary food is lantern fish. These are abundant deepwater fish that migrate to near the surface at night and then descend to between 300 and 1,500 meters before daybreak. To determine the average swim speed, we used a spring-type velocity meter. It was small enough that it had only a slight influence on the hydrodynamics of the traveling bird. We found that for the total trip at sea, averaged for five birds, swim speed was 2.1 meters per second. We also learned that the average foraging cycle was six days. The average departure mass was 12.8 kilograms, and the average stomach-content mass was 2 kilograms. That would be the maximum amount they could provide to their chicks, or it would function as a store for themselves while they fasted, if they were still incubating an egg. From our metabolic experiments, we found that the birds’ average metabolic rate while they were at sea was about 4.6 times the resting metabolic rate. This value is equivalent to a human’s increase over resting during a fast walk. No one had done any of this research on king penguins before, so it was all new and exciting information, and it would allow me to compare kings to their emperor cousins when I embarked on the similar research effort I was planning. It was also labor-intensive work, and it initially required many river crossings. The river bottom was quite slippery, and the current was often strong. To provide some measure of safety, we hammered in posts on either side of the river and strung a sturdy rope between them. On February 14, Valentine’s Day, I headed back to the hut alone, leaving Phil to finish up some work at the colony. I was about halfway across, up to my chest in the strongly flowing water and really hanging on, when the post on the hut side started to come loose. I worked my way over as quickly as I could, but the post gave way before I could make it. I was instantly submerged in ice-cold water. Our crossing point was near where the river emptied into the sea, and I had visions of being swept out to sea and weighed down to the bottom by my flooded waders. Phil would never know what happened to me. The

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other thought going through my mind was that this was a terrible way for my wife to lose her valentine! I let go of the now-useless rope and scrambled toward the shore. It was a real flail, and I was washed downriver a long way before I managed to drag myself out. Then I had to face a very cold and wet slog back to the hut to change clothes and warm up. Another South Georgia day never to be forgotten! After that little adventure, we decided to try crossing the glacier instead, although I thought that might be even more dangerous. The front of the glacier was too steep to climb, so we had to hike in a bit. It took an hour longer to get to the colony, but the views from the top were spectacular. Nonetheless, my worry about the potential danger was well placed. In the heat of the austral summer, there were fast-moving streams flowing across the glacier and forming deep cuts through the ice before they disappeared down moulins, which are holes through a glacier filled with down-rushing water. The polished ice at the edge of these streams was extremely slippery. We had crampons for our boots, but it was still unnerving to have to jump across those streams. If we slipped, we’d be washed down the stream, into the moulin, and down to the bottom of the glacier, where the stream joined other streams to form the river we had been crossing. We joked about the wild ride we’d get by “shooting the moulin,” but the truth was that it was a long drop and probably not survivable. Coming down the glacier by the colony, we skirted numerous crevasses. There were king penguins down in there. Quite a few of them, in fact, and all of them dead. For whatever the reason, some of the birds had obviously walked up on the glacier (maybe to get cool?) and fallen in. They couldn’t get out and had starved to death. Ultimately, we took either the high route or the low route to the colony, depending on our mood for the day. Either way, it was hell of a lot better than commuting to work on the freeways of Southern California, where both of us were brought up. Even with the thirty-nine deployments of recorders, the stomach lavages, and the collection of samples for determining foraging trip metabolic rates, we had a little free time on our hands. So what do two curious biologists do when they have free time from hiking back and forth to the colony? We went hiking. Our free-time hikes were much more strenuous than those we made for collecting data. To go anywhere, we had to climb substantial coastal hills and inland mountains. Nonetheless, these hikes gave us some of our finest hours. South Georgia is undoubtedly one of the most beautiful places in the world, just from a scenic perspective. On top of that, we were fortunate

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enough to see an exceptional array of wildlife for a sub-Antarctic island. Both the southern elephant seal, the largest of all pinnipeds, and the Antarctic fur seal breed on the island. Crabeater seals are often seen, and even leopard seals and Weddell seals on occasion. Among seabirds, exclusive of penguins, we saw light-mantled sooty albatrosses, giant petrels, white-chinned petrels, Wilson’s storm petrels, South Georgia diving petrels, blue-eyed cormorants, Antarctic terns, South Polar skuas, Dominican gulls, sheathbills, and a prion we couldn’t identify, though we do know that fairy prions also breed on the island. As for penguins, in addition to kings we saw macaronis, chinstraps, and gentoos, and even a juvenile Adélie. Especially noteworthy was our observation of a bird we called Othello, an all-black king penguin. When I first saw it, I did not realize the bird was facing me, because a king penguin’s front is normally white. Then, when I realized what I was seeing, its stunning beauty charmed me. We also discovered a king penguin colony of about two hundred breeding birds at Doris Bay, about 12 kilometers up the coast from Saint Andrews Bay. To see all these amazing sights (and many others), we hiked 480 kilometers over the course of our stay (according to my pedometer). On our early hikes, we also had a mission beyond sightseeing, and that was to make radio contact with the outside world. It was a safety requirement to contact the main BAS base regularly, which at this time was on Bird Island. At the same time that Phil and I were at Saint Andrews Bay, several of our friends and lab colleagues from SIO were there conducting diving studies on fur seals and macaroni and gentoo penguins. We looked forward to communicating with them, as well as doing our mandatory check-in. Unfortunately, our radio did not work well. It is against both US and British policy for anyone to be in the field in Antarctica (or in the subAntarctic, in our case) without radio communications. But despite frequent attempts, we could not contact the base at Bird Island. At first we thought we just needed more altitude, but several attempts at hauling the radio up hills around the bay were also unsuccessful. So on February 11, we made an overnight trip to another hut situated 400 meters above Hound Bay. This increased altitude gave us success at last, and we had a long conversation with a BAS biologist on Bird Island. We explained our problem, but he could offer no solution. The next morning, we returned to Saint Andrews Bay, still incommunicado. From time to time, we could hear radio communications from nearby ships, but our radio would not transmit well, and often not at all. After that one contact, we were never again able to communicate directly with Bird Island. In fact, that was our last communication with the outside world

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until we received surprise visitors on March 16. We looked up that day to see a Zodiac full of soldiers, all decked out in camouflage and carrying rifles, whizzing up to the beach. It was a rather jarring sight at first, especially since the Falklands War had not been that long ago. After watching a rather entertaining landing, Phil and I walked to the beach to greet them. It turned out that they were Royal Welsh Fusiliers from the Royal Navy ship Guardian. They were in the midst of a personnel turnover at Grytviken and had stopped by to check on us and repair our radio. Earlier I had heard them talking on the radio when they were offshore, saying there were a couple of Americans at Saint Andrews Bay that weren’t communicating, so they needed to go check their radio and get them set up. The underlying message was that we didn’t know what we were doing. This really annoyed me, especially since I couldn’t respond because our radio wouldn’t transmit. It is typical that technicians, whether military or civilian, tend not to believe it when scientists tell them a piece of equipment isn’t working. Perhaps it’s due to a lingering stereotype of scientists as hopeless klutzes when it comes to equipment. I’ve run into that attitude more than once, and this was no exception. I got the distinct feeling that this was the Royal Marine radio technician’s assumption when he sat down to work our radio. However, after fiddling around with it for quite a while, he finally gave up and said, “This doesn’t work! And I can’t fix it.” I felt vindicated. In any case, this was the first time Phil and I had seen any other humans since leaving the World Discoverer, so we had a pleasant visit. Not long after, when a Royal Navy ship was close offshore and could make radio contact, we were informed that we had two choices for being picked up. We could wait an extra month for the BAS research vessel Bransfield to pick us up, or we could be pulled out by the BAS research vessel Biscoe on March 21, just a couple of days away. As enticing as it was to spend another month at Saint Andrews Bay, I had a lot going on back in my lab at Scripps, so I opted for the earlier pull-out. On the night of the 20th, we had a huge bonfire to dispose of our own rubbish and other rubbish around the hut. The leaping flames and the shadows they cast around the camp seemed to bring out the ghosts of South Georgia. There had been much killing here in earlier years, when the huge population of fur seals was brought nearly to extinction to supply a fur trade. Next, the world’s largest concentration of great whales was nearly annihilated in the offshore waters, with the carcasses brought to Grytviken for rendering. After the whales, king penguins and elephant seals followed. In the decades since, with the end of whaling and sealing in these waters,

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all wildlife has recovered, except for the whales. In fact, the fur seal population has exploded, such that Bird Island might now be more appropriately called Fur Seal Island. South Georgia was equally rife with fur seals, and on our hikes to and from the penguin colony we often had to work our way around them as much as the elephant seals. While they were not often aggressive toward us, the same cannot be said about their interactions with the kings. Fur seal–penguin dust-ups were a fairly common occurrence (plate 2). Even worse, some fur seals had developed a taste for the birds and were killing and eating them. I couldn’t help but wonder if this was a new behavior—the unexpected result of their near extinction and recent rebound—or if it was something they had done before human hunters came on the scene. Nonetheless, it was a good time for us to be at Saint Andrews Bay, with all those animals around. My experience with field programs, beginning with my very first project at McMurdo Station in 1963, is that the first season in a new place is mainly a “proof-of-concept” endeavor. First I work out the procedures for getting there. Second, I determine whether it is the best place to do the study (and Saint Andrews Bay really wasn’t, because of the difficult access). Third, I establish a secure living environment. No two places are the same. Phil and I were prepared to live in tents, but thankfully the BAS hut made the project much more practical, requiring much less time on personal maintenance. The katabatic winds we experienced likely would have flattened the tents that we would have used, and the driving rains that occurred from time to time would have made tent living even less pleasant. The fourth element of a new field program is testing new devices, of which there are always a few. And finally, for me, I always look forward to exploring new and wonderful places and discovering new information about the natural history of the species I’m studying. I also always aim to achieve my science goals with strict attention to safety, which we did at Saint Andrews Bay. At the same time, I discovered many new problems for which the solutions would require improved instruments. The pull-out on March 21 was uneventful, especially compared to our put-in six weeks earlier. I always have bittersweet feelings when leaving a field site, but Saint Andrews Bay is such a glorious place—so pristine, so isolated, and so free of human influence—that it made my departure particularly poignant. Until the marines showed up, there had been no other voice or face except Phil’s, and often he and I were well separated from each other as we did our work. I even stopped listening to music except occasionally at dinner, because the natural sounds of wind, birds, and mammals were so much better.

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It took us nine days sailing from the sub-Antarctic to the tropics. This was plenty of time to get my mind adjusted to the fact that one of my finest field experiences was over. No more waking up to a parade of penguins outside my window. The roar of the river, the honk of the elephant seals, and, on calm days, the faint rumble of the colony three kilometers away were all gone. I miss those experiences intensely even now, years later. Most expeditions to remote field sites are followed by a few days of slow time while traveling back to civilization. It gives me the freedom to ponder the previous weeks of activities, and this time around, as always, I learned much. My occasional rants were in great contrast to Phil’s even temper. He reflected the quiet calm and stoicism of his Scandinavian ancestors. What I knew about him from his work for me at Scripps I confirmed on this trip: Phil is the Björn Borg of field science. He was completely unflappable, which made for a calm work environment, and when there was a stressful situation, he provided a level head in the crowd. In this case, the crowd was just us two. On the other hand, in moments of great triumph and exaltation, I was never sure if he grasped the significance of the moment, because he showed little emotion. On arrival in Rio de Janeiro, we said goodbye to our shipmates. Even though the masses of people were overwhelming, we spent our three-day layover doing the usual touristy things. We took the tram to Sugarloaf Mountain, the bus to Corcovado, and a walk to search for the girl from Ipanema. We did not find her, but we were harassed by a few wannabes. We were a long way from Saint Andrews Bay, but my mind was still there and working fast on plans for the future. We had proved that we could attach recorders to king penguins and recover over 95% of those deployed. This boded well for the next phase of my project, which was to apply the techniques and devices to emperor penguins in the Antarctic in a year and half. To be ready, there was much to do. I also recognized that what we had so far was an incomplete study of king penguins, and I was already thinking about where we would be able to do more. In the Crozet Archipelago, in the Indian Ocean, there was not only the greatest concentration and largest breeding colony of king penguins, but also the greatest diversity of all seabirds. There was also an established infrastructure, in the form of a French research base. So that was where I was committed to go, as soon as I could arrange it. Meanwhile, Saint Andrews Bay and the birds that live there are now, and will always be, in my spirit.

[ Ch a pt er 3 ]

The Seven Colonies of the Ross Sea

Location, location, location. A n y Ca l i fo r ni a r e a ltor

Before I could even propose an emperor penguin project to the NSF, I needed to determine which colony would serve as the best study site. There were several research stations around the continent that I considered. There is a large colony next to Russia’s Mirny Station, and no one was doing work with those birds. The US has an Antarctic science exchange program with the Russians, so that was a possibility. On the negative side was my lack of any knowledge of the Russian language, rumors about the terrible food, and the lack of timely transport. The station was supplied only by ship, which arrives in late summer. This would require me to winter over, which was not an option for me because of commitments to other projects back at SIO. At Halley Bay there was another large colony, with no research being done on the birds. Since my work on king penguins was partially sponsored by BAS, it might have been natural for this to be the site of choice. The deal breaker was again transport, which like Mirny was only by ship in the summer. I also considered using the colony near France’s Dumont d’Urville station, the site of a long-term emperor penguin study, but this had the same transport problem. In addition, the penguins there had a long march to sea to feed (as depicted in the movie March of the Penguins), and I felt this might be disadvantageous in terms of deploying and recovering my dive recorders. I would lose too much potential diving time as the birds made their way to and from the sea. All three of these sites had other disadvantages as well. In each case, my study would involve another nation’s Antarctic program and collaboration with a foreign researcher, if I could find one who was willing. I surmised that would be constraining. I preferred to work unencumbered by more bureaucratic restrictions than necessary. So despite the advantage of a

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Figure 3.1. NASA WorldView satellite image of the Ross Sea from November 7, 2015, with the locations of the seven Ross Sea emperor penguin colonies labeled with names and arrows. Major geographical features, including sea-ice conditions, are also identified.

nearby research station (and in the case of Dumont d’Urville, the attraction of French cuisine all year), I had to cross these colonies off my list. My attention turned to the six western Ross Sea colonies, none of which had been studied because all had major obstacles to access. Nonetheless, each of them had nearby access to open water, which maximizes the time the TDRs could be recording dives. The colonies were also reasonably close to McMurdo Station, which would be able to provide the considerable logistical support I would need, primarily for transport to and from the field camp. The question was: Which one should I choose? The Ross Sea is the most studied body of water in the Antarctic. It was first discovered by the British explorer James Clark Ross in January 1841, during an unusual year of scant sea ice. This serendipitous condition allowed him to sail his two ships, HMS Erebus and HMS Terror, all the way

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to 78° S, which, even now, is as far south as any ship, even icebreakers, can sail. He was stopped by a 45-to-60-meter “Perpendicular Barrier of Ice,” as he described it. (It is now called the Ross Ice Shelf.) During his 650-kilometer transit from Cape Adare at the northwest corner of the Ross Sea to the “Barrier” in the south (a distance 100 kilometers greater than the distance from Los Angeles to San Francisco), he proceeded to name every prominence in sight. What he missed seeing were the six colonies of emperor penguins that had been recently deserted by their inhabitants at the end of their breeding cycle. In 1983, the United States Geological Survey (USGS) made an aerial photographic survey of the colonies on or near the Victoria Land coast, each of them named for the nearest geographical formation. The survey was very fortunate for me, because studying these high-resolution photographs allowed me to weigh the strengths and weaknesses of each colony. I could see in detail where the birds were, approximately how many were there, and the sea-ice conditions in the area. The latter was crucial because I planned to camp on the sea ice until late December. I had to be confident that the summer break-out would not happen until after my team and I left. With that in mind, I considered each colony in turn. Cape Crozier (77.463° S; 169.083° E) (figure 3.2) was named after Francis Crozier, captain of HMS Terror. The emperor colony here was the first to be discovered, in 1902, by a member of Robert Scott’s Discovery Expedition. This is somewhat surprising, since it is the second most southerly colony. (The most southerly colony, by just a few miles, is at Gould Bay in the Weddell Sea.) For their breeding area, the birds use narrow canyons formed by the tearing of the Ross Ice Shelf as it moves past the cape. It is a small colony, which had about four hundred adults and thirty live chicks at the time of its discovery. It has sometimes had as few as three hundred adults (though by 2012 the colony had grown to about two thousand adults, based on a count of the chicks). The colony is located in rugged and unstable terrain, and the area is wind-scoured from strong katabatic winds. Beyond the colony is a limited amount of sea ice, with open water created by the cascading winds. Cape Crozier is an Antarctic Specially Protected Area (ASPA), which imparts some special limitations on any proposed research. More important, the cape’s uninviting terrain and notoriously bad weather made it a less than desirable place to conduct my study. The low number of birds would also be limiting, and accessing the colony would likely be difficult, or even dangerous. I had firsthand experience with that danger. In 1964, during the second season of my thesis project on Weddell seals, I spent a couple of days at

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Figure 3.2. This NASA satellite image of Cape Crozier shows the cape and a section of the Ross Ice Shelf. The emperor colony is in one of canyons formed when the ice shelf splits apart in its movement past the cape.

Cape Crozier with my field assistant. A recent storm had pushed sea ice into a five-meter-high wall along the shore, and Adélie penguins from a nearby colony were having a hard time scaling it. They’d jump up, lose purchase, and fall back into the water, where leopard seals were waiting for them. The leopard seals were vocalizing a lot, and I was working my way along the top of that ice cliff, trying to observe the action. I paused at one spot to lower a hydrophone into the water in order to record the seals. After a few minutes, I pulled the hydrophone up and moved to another spot nearby. Moments later, I heard this horrendous crack. The whole section where I had been standing had broken off and dropped into the water. Had I still been standing there, I would have gone for an unpleasant and probably fatal swim. Because of the undercut structure, height, and extensiveness of the ledge, there would have been no way for me to get out of the water, and my assistant wasn’t near enough to see what had happened. I would have just disappeared without a trace. Beaufort Island (76.960° S; 167.083° E) (figure 3.3), named after Sir Francis Beaufort, hydrographer for the British Royal Navy, is a few kilometers north of Cape Bird, on the other side of Ross Island from Cape Crozier. The emperor colony here has perhaps slightly friendlier weather because it is not subject to the frequent hurricane-force winds of Cape Crozier. The emperor penguin population is also small, though it once was about double that of Cape Crozier. (The breeding populations of both colonies are highly variable from year to year.)

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Figure 3.3. An aerial photo of Beaufort Island’s northwest side. The penguin colony (consisting of about 500 adult pairs) is next to the middle of the exposed cliff. The fast-ice skirt is about 300 meters wide.

The colony is limited by the small area of fast ice on the rugged eastern side of the island, which forces the birds up against steep cliffs for all or most of the breeding season. If there is no clean ice to the north, the birds are forced to live in crowded conditions with heavily guano-contaminated snow. This is undrinkable and inedible, soils their down, and creates a surface that becomes pitted when the sun’s heat makes the dark guano sink into the snow. This surface is difficult to walk over, especially for the chicks. It would be just as bad for scientists. In addition, USAP helicopters are not allowed to fly over open water, and in most years there is no stable fast ice between Ross Island and Beaufort Island. The limited sea ice there also has insufficient room for airplanes to land. The poor conditions and difficulty (or even impossibility) of setting up a camp there made Beaufort Island a bad choice for my project. Franklin Island (76.178° S; 168.396° E) (figure 3.4), discovered January 27, 1841, was named for Sir John Franklin, a noted Arctic explorer who was at the time governor of Tasmania. The emperor penguin colony was discovered by Bernard Stonehouse in 1964 as he flew by during an aerial reconnaissance. It is the most isolated of the six coastal colonies of Victoria Land and is well offshore, where the only fast ice is that which circles the island. It has never been visited while the birds are present. (Other than a brief landing in hazardous conditions by James Clark Ross’s crew, the only other recorded visit to my knowledge was one I made with my son Carsten and a helicopter crew from the US Coast Guard icebreaker Polar Sea in

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Sea Ice Sea ice takes many forms, depending on weather, sea conditions, water temperature, salinity, geographical features, and other factors. Depending on its age and thickness, the ice will be blue (multiyear ice), milky white (new, thick ice), gray (newly freezing, soft, thin ice), or black (frozen but very thin ice). These are the most common forms that I dealt with in my work: Fast ice is attached to a geographical feature; in other words, it is fast against a shore, glacier, or iceberg. It is generally the most stable sea ice, as long as temperatures and other conditions are conducive, and it can stretch out from shore for tens of kilometers. As long as it is thick enough, fast ice provides the best working platform for both humans and animals, accommodating vehicles, planes, and camps, as well as emperor penguin colonies. Pack ice consists of free-floating ice floes unconnected to any shoreline. Pack ice can be consolidated, where the floes are frozen together, or loose and in varying concentrations, from near complete coverage to open pack, in which substantial open water is visible and the floes are not generally in contact with each other. Temporary camps have been placed on consolidated pack ice, but in general pack ice is a less secure platform, as the floes will move around and may break up in response to wind or waves. Pancake ice consists of loose pieces of pack ice that, in the early stages of formation, batter each other because of wind and waves to form small, round floes of similar size that look like pancakes with curled edges. Brash ice is floating ice composed of smaller fragments, generally the wreckage of formerly fast or pack ice that has been broken up by weather and waves. Grease ice is newly freezing ice that forms a thin, soft layer on the surface and looks like an oil slick. Platelet ice is composed of small, newly frozen plates that form a layer of varying thickness on the underside of fast or pack ice. If the layer is disturbed, and if it is thick enough, the plates can dislodge, float up, and plug a breathing hole that may be providing access to the surface for seals or penguins (or humans).

early January 1990. All birds had departed, but we were able to explore the breeding area where they had been.) This is also a small colony, and like the Cape Crozier and Beaufort Island colonies, it has experienced wide swings in its population. For essentially the same reasons as Beaufort Island, Franklin Island was a poor choice for my project. Coulman Island (73.333° S; 169.6333° E) (figure 3.5) was named for Ross’s father-in-law, Thomas Coulman. Ross apparently had a contentious rela-

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Figure 3.4. The southern half of Franklin Island. In this photo, the island is surrounded by pack ice, except for the narrow field of fast ice next to the eastern side of the island, where the colony is normally located, as evidenced by the dark stain in Bernacchi Bay. This colony has about five thousand adult pairs.

tionship with him, so perhaps he was trying to get in Coulman’s good graces. After all, who wouldn’t like a son-in-law who would do such a nice thing? The emperor penguin colony there was discovered on December 6, 1958, by two researchers working out of the Naval Air Facility McMurdo (later named McMurdo Station). They attempted the first count of any western Ross Sea colony other than those made at Cape Crozier. This was especially significant because Coulman Island was then and still is the largest known colony. The researchers estimated that there were about thirty-three thousand pairs of adult birds. Coulman Island is a high, ice-capped island of overlapping volcanoes, with sheer cliffs, steep slopes, and numerous hanging glaciers on the western side, where the penguins establish their colony. The island also has a large fast-ice field that stretches to the coast of the Antarctic Continent, about 40 kilometers away. The ice near the island is covered with a thick layer of snow, which (as I discovered later) depresses the sea ice with its weight and causes it to flood from nearby tidal cracks. That heavy snow de-

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Figure 3.5. The northwest quarter of Coulman Island. The island is completely ice capped, with hanging glaciers. The colony (about twenty-five thousand adult pairs at last count) is divided into many suburbs, of which about ten can be seen as dark patches. All suburbs are on the move to the north, where they can access the open water that consistently occurs on the east side of the island.

position during winter and spring also buries any trace of abandoned eggs, dead chicks, or guano deposited during the incubation, making it difficult to determine the penguins’ preferred incubation area. Although it was tempting to conduct my research at the largest colony, its distance from McMurdo made logistics more difficult. The US Navy skiequipped LC-130 (“Hercules”) aircraft we would need for transport were not permitted to land on sea ice that had not been cored to confirm it was thick enough to support such a large aircraft, and there was no other way to get to the island to do that coring. (The constantly flooding of the sea ice would also have been a serious problem for a tent camp, as I discovered later.) I had to conclude, reluctantly, that Coulman Island was a less-thanideal choice. The farthest-north Ross Sea emperor colony is at Cape Roget (71.977° S; 170.532° E) (figure 3.6), which Ross named for Peter Mark Roget, an English lexicographer and secretary of the Royal Society. The colony, discovered during an aerial survey on November 9, 1964, lies at the head of the Moubray Glacier, named for George Moubray, the clerk in charge of HMS Terror. The glacier-capped cape is southeast of the colony. The Admiralty Mountains to the northwest provide a towering background to perhaps the most beautiful setting of all emperor penguin colonies. In early morning, alpenglow sets the mountain landscape afire, and with the colony resting on deep snow blanketing the fast ice, it’s a scene that is one of Mother Nature’s best (plate 3).

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Coulman Island I was finally able to visit the Coulman Island colony in 1990. My friend and colleague Paul Ponganis and I were flown to the island by helicopter from Italy’s Zucchelli Station for what was supposed to be a one-day visit. The weather had different ideas, and we ended up stranded there for four days. All we had was survival gear, which included a camp stove that, try as we might, we could not get started. We had to melt snow in bottles next to us in our sleeping bags in order to have water for drinking. Finally, on the last morning, shortly before we were “rescued,” Paul managed to get the stove working. One of the first things we discovered while we were there was that avalanches from the hanging glaciers are frequent. The booming, thunderous roar of cascading snow punctuated our days, which made me think a better name for the place would be Thunder Island. On my second visit, in 1992, we established a temporary field camp, with the intention to stay for three weeks, until the end of December. Unfortunately, the weather was so foul that it was hard to get anything done. Most of the time we couldn’t see very far because the wind was blowing so much snow around. It would blow from the south, then there would be a brief respite before the wind would turn around and blow from the north. I had better luck on my third visit, in 1993. However, the constant flooding of the sea ice from the weight of all the snow was a serious problem, and we had to keep moving our camp to stay dry. In the Coulman colony, when the eggs have hatched and chick nurturing begins, the adults start moving around right away, unlike at Cape Washington, where they take their time. I wanted to dig down through the snow to see if I could pinpoint the incubation area and then count the guano layers, but I never had the opportunity. When the Twin Otter came to get us, the ice had degraded to the point that the airplane’s skis broke through the rotten snow as it taxied, causing the plane to rock from side to side. The pilot was supposed to make two trips to retrieve my team and all our gear, but he was not happy about the ice conditions and decided he and his copilot would cram everything in on one flight. When we took off, the cabin was packed to the ceiling. From my seat up front near the cockpit, I couldn’t even see the two people in the back.

The colony seemed an ideal, protected place, but the fast-ice area was limited and the edge was perhaps too close to the colony. The potential for an early ice break-out was a negative factor. It is also the most distant from McMurdo Station, which would have presented logistical problems, and as with Coulman Island, there was no way to get there and core the ice

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Figure 3.6. The Cape Roget colony (consisting of about 5,500 adult pairs) is the large stain on the fast ice, adjacent to the glacier. This aerial photo was taken from southwest of the colony.

so the LC-130s could land. I struck the Cape Roget colony from my list of potential sites. Cape Colbeck (77.133° S; 157.617° W) was discovered in 1902 and named for Captain William Colbeck of the steam yacht Morning, relief ship on Scott’s first expedition to the Antarctic. In January, as the expedition sailed by, E. Wilson noted that he thought an emperor penguin colony might be in the vicinity because of the large number of penguins he saw at the ice edge. The colony itself wasn’t discovered until Christmas Day of 1962, by members of the Marie Byrd Land Expedition. However, it was never officially reported except to the cartographer that placed a penguin symbol on an obscure map of the area. Therefore, in my evaluation of emperor colonies, I was aware only of Wilson’s hint that a colony existed. A hint wasn’t enough upon which to base a research project, and I didn’t have the ability to confirm its existence or assess its practicality before submitting my proposal. Finally in my assessment of Ross Sea colonies, there was Cape Washington (74.643° S; 165.382° E) (figure 3.7), which Ross named for Captain John Washington of the Royal Navy, who was secretary of the Royal Geo-

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Figure 3.7. In this photo, looking toward the west and taken from about 10 kilometers away, Cape Washington is the dark bluff at the end of the peninsula that juts left in the center of the frame. The colony, consisting of about twenty thousand adult pairs, is barely visible as a faint smudge in the shadow on the other side of the cape. The cape locks in the northeast section of Terra Nova Bay’s fast ice. Mount Melbourne, an extinct volcano, is to the far right.

Cape Colbeck Though I couldn’t reasonably consider it as an option at the time of my review, the possibility that there was a colony at Colbeck was intriguing. Unaware of the 1962 expedition, I resolved to try and find it if I could. I got my first chance in 1988, when a Twin Otter became available. I made a flight along the entire face of the Ross Ice Shelf, searching for an inlet similar to Cape Crozier, and found nothing. As we approached Cape Colbeck, the weather shut down on us and we had to turn back. Before we did, I noted many birds at the fast-ice edge in the area and believed this was confirmation of a colony. What a frustration not to be able to explore further. In 1993, I planned another search. Because of the distance across the Ross Ice Shelf from McMurdo Station, this was a two-plane operation. The first plane established a fuel cache most of the way across the shelf. This allowed our search plane to top off its tanks before carrying on to Cape Colbeck. There were four of us on the flight: myself, my two sons Carsten and Tory, and Graham Robertson, an Australian biologist. At first we overshot the cape and penetrated deep into Sulzberger Bay without seeing anything. Disheartened but still searching, we climbed to altitude and turned back to the west. A little later, Tory called out from the back of the cabin that he saw a dark patch near the horizon. Sitting in the cockpit, I had missed it. It could be nothing other than penguins amid all this white ice, and Tory had saved the day. Eureka! The pilot made a hard right turn and landed in a strong wind and blowing snow. As soon as the plane stopped sliding across the snow, the pilot turned to me and

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said, “You have twenty minutes.” To my surprise, he shut the engines down. I had never seen any of the other pilots do that in remote areas. We all piled out to be greeted by a suburb of the main colony, a large contingent of birds strung out across the heavily snow-covered fast ice. There was no time to go to the main colony, so we attached satellite transmitters to two nearby birds to learn where they might be foraging. Then we did a fast walk around to assess the area and were back in the plane within twenty minutes. Without delay, the pilot started the engines and we were away. During our return flight across the vast Ross Ice Shelf, I thought to myself, “Nothing makes for a good day better than discovering a new emperor penguin colony.” Back at McMurdo Station later that day, the pilot and I did a thorough search of navigation charts, and on one of them, to my chagrin, we discovered the penguin icon from 1962. The colony is situated in an inlet about 10 to 15 kilometers south of the ice edge. I had planned to propose to name the inlet after my wife, Melba, but I was too late. It had already been named for Lieutenant Eugene F. Bartlett, the US Navy officer in charge at Byrd Station in 1960. Because the Marie Byrd Land Expedition had discovered the colony so late in the 1962 season, even if they had done a count (and they didn’t), it would not have been accurate because many of the chicks would have left by then. So I began making

Figure 3.8. An overhead view of Bartlett Inlet, near Cape Colbeck. The cape is to the north (not visible) and the birds (barely seen as a dark smudge because of blowing snow and iceberg shadow) are about 10 kilometers from the ice edge. At last count, the colony had about seventeen thousand adult pairs.

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plans to return the following year and do a thorough count. The flight back would be much shorter because we had GPS coordinates and could go there directly. I returned the next year with Carsten and Tory and learned much more about the colony. It is set in an icescape of buried hills and mountains, with no rock showing anywhere nearby, and is only slightly less than 32 kilometers farther north than Cape Crozier, making it the third most southerly colony. It is, however, much larger than the Cape Crozier colony—an important and intriguing difference. The area around the colony is notorious for stormy weather and overcast skies. The penguins are located under high ice cliffs, in the lee of the prevailing winds. The snow covering the fast ice gives the birds considerable area to expand into fresh snow, but surprisingly they remain clustered near the incubation location (figure 3.8). This is yet another mystery about emperor penguins. Most likely they do this because of the considerable snowfall in the area, as there may be no need to continually seek out fresh snow to eat.

graphical Society from 1836 to 1840. He had agitated for an Antarctic expedition and promoted the selection of Ross to be the leader. The emperor colony was discovered on October 29, 1965, by a New Zealand ornithologist during a flyby. It was also photographed in 1968 by a biologist with the New Zealand Antarctic Research Programme doing an aerial survey of seals, but at the time of my aerial photo analysis in 1983, it still had not been visited, so I had no direct on-site data to help my decision. However, I had been in the general area before. Cape Washington is located in Terra Nova Bay (named by Scott for the flagship of his second Antarctic expedition in 1911). In early January 1979, a small team of postdoctoral students, technicians, and myself camped at the site where the present German, Korean, and Chinese stations now stand. The next morning, we witnessed a graphic demonstration of how rapidly the sea-ice conditions change in Terra Nova Bay. The entire bay on both sides of the Campbell Glacier Tongue broke out in a matter of hours. For information on the early season at Cape Washington, when I would be there for my study, all I had were the USGS photos. Based on those, this colony had a lot going for it. The breeding area showed that it was a large colony—much larger than Cape Crozier, Beaufort Island, or Franklin Island. And even though it was 320 kilometers from McMurdo Station, it was closer than either Coulman Island or Cape Roget. Since the LC-130 Hercules pilots couldn’t land us on Terra Nova Bay’s fast ice unless it was cored (which wasn’t possible), I deduced they would be able to land us on the nearby Priestley Glacier. We could then traverse the distance to the colony on snowmobiles. At the end of the season, we could

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be picked up by the annual icebreaker, which opens a channel through the McMurdo Sound sea ice so cargo vessels can resupply the station. The photos showed a massive expanse of fast ice in the bay, which made it unlikely it would break out prematurely. A camp there would be safe until late in the season, and there was little likelihood of a disruption to the breeding cycle (or my research) caused by early break-out. Ultimately, two things were clear from my analysis of the aerial photographs. First, all the Ross Sea colonies are located on fields of fast ice (some of them quite large), and they are close to an ice edge. The ice expanse gives them ample room to breed and to nurture their chicks, and the nearness of the edge gives the birds ready access to food resources, which in turn promotes success in raising chicks and perhaps even allows for some feeding by adults shortly before breeding. Close access to open water also helps chicks leave the colony during fledging. These advantages are undoubtedly why four of the seven Ross Sea colonies are among the largest of all emperor colonies. All of them are also deeper south than most emperor colonies—in par-

Colonies As of this writing, there are sixty-three known colonies, most of them discovered through satellite imagery. The telltale sign of a black guano stain on white ice gives away even the smallest collection of birds, even from 450 kilometers above Earth. Most of the recent discoveries have not been visited, and some may never be because of their remote locations. Except for those in the Weddell and Ross Seas, emperor colonies are spaced about 50 to 100 kilometers apart around the perimeter of the Antarctic Continent. Colony sizes fluctuate from year to year and can change dramatically. For example, Cape Crozier has seen as few as zero adult pairs and as many as two thousand. The counts listed in the text and captions were made between 2000 and 2012 and reflect a snapshot of the populations at the time the count was taken. The most recent count puts the total population of Ross Sea emperors at about seventy-three thousand adult pairs (146,000 birds), but this does not include birds in the water or subadults that had not returned to the colony to mate, so the number is probably higher. Scientists frequently suggest further research is needed, and in this case that is very true, because large trends in the Ross Sea emperor population, either up or down, can be identified only by regular counts. This is particularly important because these penguins can be considered an indicator species, one whose population trend demonstrates the variable status of the Ross Sea ecosystem.

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ticular the northern colonies, where much of the previous research had been done (primarily at Dumont d’Urville) and upon which the scientific conclusions about this species were made. I suspected my research might lead to new and different insights into how this species has carved out a relatively peaceful life in a seemingly impossible place for a surface-dwelling, warm-blooded, flightless bird. Second, the aerial survey left no question that the best place to conduct the studies I had in mind was Cape Washington. What a lucky break that such an ideal and beautiful place was so close to McMurdo Station (plate 4).

[ Ch a pter 4 ]

The Emperors of Cape Washington

Exploring the unknown requires tolerating uncertainty. Br i a n Gr een e

The big LC-130 Hercules aircraft was taking a beating. Loud knocks and bangs that even the roar of the four massive engines couldn’t mask reverberated through the cargo hold. The flight crew was “dragging the strip,” a procedure whereby the pilot lands the plane—but not really. At high power and with a so-called light touch, our pilot skipped from one hard-packed sastrugi mound to the next, each one delivering a resounding blow to the plane’s skis that shuddered through the airframe. The idea was to shake loose snow bridges that might be masking crevasses, any one of which would force us to either find another landing site or, the worst of all possible outcomes from my perspective, abort the mission altogether. The pilot’s original plan was to land in Browning Pass, but the crosswinds there were so strong that the massive plane was tossed around as violently as a Piper Cub in a hurricane. The only thing that prevented my team and I from becoming airborne inside the aircraft were our shoulder straps, and we strained heavily against them. So we all breathed a sigh of relief when the pilot said we would try for the Priestley Glacier. Anything had to be better than Browning Pass. Or so I thought, until we started dragging the strip. It was like driving over a heavily washboarded road at 130 kilometers per hour. Inside the aircraft things were creeping and groaning, and fuselage struts were flexing. After skipping along over the glacier’s surface, the pilot swung around, made a low pass, and confirmed there were no cracks in the “runway.” Then he dragged the field two more times, just to be sure. Or was he just having fun with the green scientists in his hold? After the third jaw-rattling pass revealed no landing hazards, the plane made a full-stop landing. Finally! Like the tongue of a yawning dragon, the giant ramp at the back of the

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Figure 4.1. The 1986 field team and penguin greeting party. From left to right: Steve Smith, Don Croll, Sheridan Stone, and Jerry Kooyman.

Sastrugi The term sastrugi is the plural form of sastruga, a Russian word meaning “groove, small ridge, or furrow.” Sastrugi are long, irregular ridges of snow running parallel to the prevailing wind direction that sometimes resemble waves. Formed by wind simultaneously depositing and eroding snow, they are common in polar regions and can be several meters high.

plane dropped to the hard sastrugi, opening the cargo hold to the frigid Antarctic air. I unstrapped myself, grabbed the ultra-high-frequency (UHF) radio we would use for communication, and scrambled down to the ice. While my teammates started up our snowmobiles and maneuvered them down the ramp, I moved a hundred meters away from the roar of the four turboprops and tried to contact McMurdo Station. Establishing communication is a requirement for every aerial put-in to a field camp. This tells McMurdo Station staff that the field party has landed

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safely, and most important, that the field team has established secure communication with the base. It’s sometimes easier said than done. Solar flares interfere greatly with UHF frequencies, and that appeared to be the problem for me. After yelling into the mike over the background noise for several minutes, I was only able to reach South Pole Station. They agreed to relay to McMurdo that we had landed and operations were normal. Normal! This was anything but normal! It was October 22, 1986, and this was likely the first time anyone had landed an airplane on the Priestley Glacier (plate 5). It was also the first time the NSF had authorized any science team to establish a fast-ice field camp so far from McMurdo Station. I didn‘t have time to ponder it. With our gear unloaded and communication with McMurdo confirmed, the roar of the LC-130’s engines increased as it made its takeoff run. We cheered and waved as it made a low pass overhead then gained altitude and disappeared to the south, leaving us with only the low rumble of the snowmobiles to break the silence. I had been wondering during the rough landing and even after leaving the aircraft whether this whole project was a good idea. Now here we were, over 300 kilometers from any help, with two tons of camping gear piled all around, standing in the middle of the Priestley Glacier, one of the windiest places on the planet. Early explorers had aptly named the spot Hell’s Gate, and we had to get the hell out of there. Were we nuts? No, except perhaps for me, the leader of this expedition. Nonetheless, this was one of the most memorable days of my life. After all my years of dreaming and planning, I was at last at the threshold of conducting the US Antarctic Program’s first major research campaign on emperor penguin diving physiology and behavior, right in the colony itself. But first we had to get there, and there was a long and potentially dangerous journey ahead. Fortunately, despite its hellish name, the winds were calm on the Priestley Glacier. It was the year of Halley’s Comet, and clearly the stars were in alignment. By 5 p.m., after several hours of lashing our gear onto the sleds and attaching them to the snowmobiles, we were ready to go. Before us was the gentle slope of Browning Pass, a slope too tame for any skier to even consider, but for us the mystery and challenge were great. I’ve always been keenly interested in the history of Antarctic exploration, and the area we were in was steeped in it. During Robert Scott’s 1910– 1913 Terra Nova Expedition, six men known as the Northern Party had explored this area and spent the winter, as planned. When their expected pick-up by ship didn’t materialize the following summer, and with their supplies nearly exhausted, they spent a second winter of severe privation at Inexpressible Island, a few kilometers south of where we stood. Their names, attached to some of the most prominent landmarks around

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us, were magic to me. Priestley Glacier was named for Raymond Priestley, a geologist and the only civilian member of the party. Browning Pass was named after seaman Frank Browning, who came closest to dying during that awful second winter. The Campbell Glacier, which we would soon be crossing, was named for Victor Campbell. As the senior naval officer after Scott’s death, he assumed command of the expedition after returning to the Cape Evans base. Mount Abbott, a beacon in the soft sunlight, was named after Royal Navy petty officer George Abbott. Our goal was to traverse 30 kilometers up Browning Pass to the Campbell Glacier Tongue, cross the 5-kilometer width of the tongue on a tortuous path to avoid the largest crevasses, and camp at Shield Nunatak. From there we would lower our gear and snowmobiles down the only slope into the bay, which is otherwise bordered by 15-to-20-meter sheer ice cliffs. Then it was 15 kilometers to Markham Island, where 3,600 kilograms of supplies were waiting—intact I hoped. They had been airdropped there a few days earlier. After that, it was an easy 20 kilometers across the sea ice of Terra Nova Bay to the colony at Cape Washington. The whole journey would be about 70 kilometers as the skua flies. At the entrance to Browning Pass, we were greeted by a faint, slumping line running perpendicular to our path. I pulled out the long, thin aluminum pole specially designed for crevasse detection and approached carefully. After pushing the pole into the snow about a meter, resistance disappeared and it went down easily the rest of its three-meter length. I was not pleased to run into a crevasse so early into our journey. This one was about a meter wide, big enough to devour a snowmobile, but we decided the snow bridge was solid enough as long as we didn’t dally on our way across. For the next couple of hours, our train of two snowmobiles and three heavily loaded Nansen sleds moved slowly over the rough surface of the pass. The only interruption occurred when one of the sleds holding two barrels of fuel started to tip over and we had to stop and correct the problem. The sky faded from blue to gray, the surrounding mountains disappeared in haze, the wind freshened, and the temperature dropped. Suddenly, a strange object appeared a short distance in front of us. It was hard to discern what it was in the low light. As we got closer, I could

Nunatak A nunatak is an isolated mountain peak or ridge protruding from an ice field or glacier, where the ice covers the rest of the mountain or ridge.

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Figure 4.2. A NASA satellite image of Terra Nova Bay and Cape Washington showing our track from Priestley Glacier up Browning Pass to our first camp at the edge of Campbell Glacier, across the glacier to our second camp at Shield Nunatak, then to our camp near Markham Island, and finally to our season camp at Cape Washington. (Modified by G. Kooyman.)

see why. It was a weather station, a white box mounted on legs almost two meters high, set up in the middle of what would have been our landing strip if we had been able to land in Browning Pass. Who put it there, and why were the pilots not informed of it? It could have easily taken out the plane. Lucky for us that those crosswinds were so strong, even though it made our traverse a few kilometers longer. Finally, several hours after our drop-off, we pulled up at the edge of the Campbell Glacier Tongue. This would be our greatest obstacle—and my greatest concern as to whether we would actually get to the colony. Our route across was heavily crevassed, and some of my advisors were not encouraging about our chance of success. In fact, one geologist had been particularly negative in his assessment and told the NSF I would never be able to cross the Campbell. But he had seen it only in the summer. I had studied early-season aerial photographs and was confident I could cross it safely in

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October, when the snow bridges over crevasses were still thick and firm from winter. In any case, there was no other option, as that was the only way to get to the single snow ramp that led to the sea ice. Fortunately, I was able to convince the NSF to fund my project, but the caveat was that I had to include two experienced mountaineers in my field party. It was a price I was willing to pay. One of the mountaineers was Steve Smith, who had a lot of experience on Canadian mountains and glaciers but none in Antarctica. The other was Sheridan Stone, who had less mountaineering experience but had worked several seasons in Antarctica. Both had undergraduate degrees in biology, which was a plus. Steve had studied marbled murrelets on Vancouver Island, and Sheridan had worked on Weddell seals in McMurdo Sound and leopard seals in the Antarctic Peninsula region. Sheridan was so keen to be on this expedition that he had quit his steady job with US Fish and Wildlife Service. The fourth member of the team was my new graduate student, Don Croll, who also had research experience with marine birds. We set up camp, which consisted of two rugged cone-shaped Scott polar tents. Our plan was to get a fresh start in the morning, with a hope the weather would be good. No wind would be nice, but clear skies would be essential for good surface definition as we picked our way across the crevasse fields. We slept miserably that night. Our lightweight sleeping bags were good only to about −10°C (14°F), and it must have been about −30°C (−22°F). We slept with our clothes, vests, gloves, and hats on, and we were still cold. The morning dawned crisp and clear. I was up before the rest to make the radio check-in with McMurdo Station. McMurdo preferred morning reports, which was a real challenge for me, as my tendency in Antarctica was to work late and sleep in to allow for the tent to warm up a little, especially since much of the radio communication procedure required bare hands. I hastily reported that operations were normal and signed off. Once again, normal was a relative term. Cold and lack of sleep meant that no one was moving very lively. Under these conditions, it seemed like our plan for a two-month field operation would seem more like two years before we were finished. It took us over two hours to eat, pack the sleds, and get ready for the crossing. Even in our hurry to get underway, I had to pause for a moment to take in the view. Looking down to the right from my vantage point on the glacier, I could almost see my 1979 campsite. The whole of ice-covered Terra Nova Bay stretched out to the east beyond that. To the north, the snowcovered, symmetric cone of Mount Melbourne rose to a cloudless sky. To be standing there, where no human had ever stood (apart from perhaps

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members of Scott’s Northern Party), and on my way to a research project I had longed dreamed about, was no small wonder to me. I couldn’t hesitate too long. Our goal was to be across the Campbell by the end of the day and camp on the glacier next to Shield Nunatak. The nunatak was not that far away, but we knew the route would not be direct. Armed with aerial photographs and the circuitous route Steve had drawn on them to avoid the worst areas, and with a certain amount of trepidation, we launched our two snowmobiles and three heavily laden sleds by midmorning. Steve and Don were in the lead, with Sheridan and me behind. We hit crevasses almost immediately. The lead snowmobile was breaking snow bridges as it crossed them, leaving Sheridan and me to dodge the broken section and hope the rest held. It was unnerving to keep looking down into these dark, seemingly bottomless chasms. At the first opportunity, I sped up to Steve and flagged him down. “Hey!” I said. “These are crevasses we’re crossing!” “I know!” “Can’t we go around them?” “There’s nothing we can do about it! We’re out in it!” Then he added, “Geez! I’ve never seen anything like this in Canada!” Great, I thought. This guy’s my expert and I know more about this than he does! It wasn’t very reassuring. Most of the crevasses were narrow enough that there was no slumping of the snow bridge, making them essentially invisible. So even though they seemed to have the spacing of railroad ties, their narrowness was such that the snowmobile runners could span them easily. I resolved to only worry about the big ones, which I assumed we’d see because the snow bridge would slump. In any case, there was really no other way to go. When we’d get off the snowmobiles for a break, we’d keep one hand on a snowmobile or a Nansen sled, even when walking around, so we’d have something to grab if we broke through a hidden crevasse. The song “Tiptoe through the Tulips” kept running through my mind. Finally, after a stressful day and a very circuitous route, and after skirting some very big holes, we arrived at our Shield Nunatak campsite and relaxed, thinking we were clear of the glacier’s hazards. We walked around the campsite without worrying about crevasses, and it wasn’t until much later on an overflight that I saw our “safe haven” next to the nunatak was littered with them. It just took a little spring sunshine to melt the bridges so they were visible. At the evening meal we toasted to our success and agreed unanimously that we would not be home for Christmas. Our plan A had involved tra-

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versing back to the Priestley Glacier for a pick-up by the LC-130. That was clearly not happening. Not only were the navy pilots disinclined to land on that glacier again, but there would be no way we could safely cross the Campbell once summer’s heat melted all the snow bridges. We only had to hope that the annual icebreaker crew would be able to pick us up in early January—our plan B. I did not relish the thought of wintering over like the Northern Party. The next day, we located the snow chute down to the sea ice. It was something we could have walked down in thirty seconds, but it took us several hours to negotiate with our snowmobiles and two tons of gear. It was now October 24, and there were now no other obstacles on our way to the colony. We spent the rest of the day driving the 20 kilometers to Markham Island. It was a relief to be on solid sea ice and unconcerned about crevasses. Unfortunately, the wind had kicked up and visibility was diminishing in blowing snow. In conditions such as this, there could be clear skies overhead and visibility to the horizon six meters above the ground, but nearzero visibility below that. The deteriorating situation caused me some concern about finding my cargo; at the time, there was no such thing as GPS. We were in luck, though, and found the airdrop site with little difficulty. All the fuel drums, food, and equipment were scattered over a small area and, surprising to me, they were in good shape. Everything was still strapped onto wooden pallets, with the high-velocity parachutes still attached. I had accompanied the drop and watched as the US Navy loadmaster shoved each pallet down the LC-130’s ramp and out of the aircraft at two hundred miles per hour, about three hundred meters off the ground. I was standing next to the loadmaster, watching as the first pallets hit the ice, and wasn’t reassured when he uttered an expletive. Some of the parachutes had not opened. I hoped it didn’t matter. Their main function was not to slow the packages down but rather to keep them oriented so they landed upright. To cushion the impact, there was a thick layer of cardboard cells—a shock absorber, essentially—sandwiched between the pallet and the cargo. It seemed to have worked. A quick inventory revealed little damage to our cargo. Fighting the wind, we set up the tents and had a hot meal. Anticipation was high for the next day, when we would make it to the colony. We were up by 5 a.m., and while Steve and Don worked on the airdrop cargo, Sheridan and I took a load of supplies across the last 20 kilometers of sea ice to the colony. The wind had died, the sky was a rich cerulean blue, and the world sparkled like a crystal desert, as the author David Campbell so aptly named it. I could hardly contain my excitement as we closed on

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Cape Washington, a prominent volcanic buttress that looked like a ship’s bow plowing into the Ross Sea. Penguins began to appear near our track, and as we got closer to the cape the encounters increased. Soon we could see a long black line extending from the cape to the west. On a whim, I stopped and shut down the snowmobile’s engine. In the sudden silence, we could hear the low rumble of tens of thousands of birds vocalizing. Sheridan and I glanced at each other, the expression on our faces revealing what we were feeling. We were the first humans in history to hear this sound, the first to stand here on the sea ice within earshot of this vast colony of emperors. We started up the snowmobiles and hastened to a spot about two kilometers from the northern edge of the colony, where we would establish camp. As we unloaded the sled, small groups of the birds trundled up to us, with more approaching in lines from the colony. Emperors are insatiably curious and will approach any upright object on the ice. Surely, we must have seemed an exotic anomaly to them, the first humans they had ever seen. Even at this distance, I could see that early estimates of the Cape Washington population, based on two flyovers decades ago, were way too conservative. The colony was many times larger than published reports described. This was not a small village (plate 6). This was penguin city! It was breathtaking. I could not have been more excited than if I had just discovered King Tut’s tomb. Only instead of finding gold trinkets, we were soon surrounded by magnificent, golden-breasted penguins. We couldn’t linger, though. The day’s gentle breeze was turning into a gale. As soon as our tent was set up, we headed back to Markham Island, and all four of us returned with the WeatherPort, a two-by-three-meter, Quonset-like hut that would serve as our kitchen, science lab, and reading room. Thanks to practice at McMurdo Station during our field preparations, it took us only two hours to set it up, with all our efforts under the supervision of the hundred or so penguins that had joined the camp. We finished in time to enjoy a midnight sunset. The next few days were filled with camp organization. Before our curious neighbors fouled it with their guano, we had to fence off a sizable section of clean snow for use as drinking water. We dug a “freezer box” into the snow to store our frozen food, and we set up the kitchen and laboratory in the WeatherPort. We also had to construct a privy out of ice blocks, which gave a new meaning to the term outhouse, for it was certainly “out there” and exposed to the elements. Four days after our arrival at the colony, we began to deploy TDRs. It was a moment I had been anticipating since 1969.

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I had been in McMurdo that year as part of a Weddell seal physiology research project and one day had an opportunity to visit the emperor penguin colony at Cape Crozier. I noticed a situation that occurred only during a rare string of very cold, calm days. New, thin ice had created an extension to the much thicker fast ice formed during the winter. Emperor penguins were traveling to and from their feeding grounds through several holes in this ice. Its thinness made it possible for the penguins to penetrate to the water and keep the holes open with their coming and goings. I gingerly shuffled out a few hundred meters to join the birds gathered around one of the holes. The ice was as smooth as a tennis court and about 20 centimeters thick where I was standing. Each time a bird catapulted itself from the water and flopped onto its belly, as emperors do, the ice flexed like a waterbed. This was too good to be true. No one had ever made diving-depth measurements of penguins—or any other bird, for that matter—but because of my work with the seals, I had with me the technology to do just that. This was a golden opportunity. As soon as I got back to McMurdo Station, I requested and received approval from the NSF representative to go back to Crozier as soon as it could be scheduled in order to conduct an experiment. I hoped the conditions would last. Thin ice is fragile and Cape Crozier is a notoriously windy place. Any storm would blow the ice out. I returned by US Navy helicopter two days later with my assistant Walt Campbell and two observers. Thankfully, the day was clear and calm. Perfect, especially for the calm. When working on thin ice, one does not want a wind blowing seaward. The ice can part at any time, and you can be heading out to sea without knowing it until it’s too late. We remained on thick ice to capture birds that were walking toward the holes and attached capillary depth tubes to their feathers. We had been allotted only four hours of ground time to do the whole experiment, so we had to work fast and soon had attached tubes to several birds. Since there were several holes, it was like a shell game trying to guess which one the penguins would return to and whether the ice thickness there made it suitable for a recapture. The operation was not flawless; the helicopter pilot, in his enthusiasm to participate and tackle a bird, fell on a piece of rafted ice and broke his nose. Soon our time was up. By then, we had retrieved five of the tubes, and I was ecstatic. The pilot said he felt fine enough to fly us back, despite his swollen and bloody nose. I wondered aloud if it would be possible to make a quick stop at Igloo Spur to visit the campsite that Edward Wilson, Birdie Bowers, and Apsley Cherry-Garrard had used, and which Cherry-Garrard

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described so vividly in his book The Worst Journey in the World. It was really asking too much of the pilot, but he wanted to see it as well. We landed on a knoll above the spur and walked about 200 meters down the hill to the campsite. On the way, Walt took a fall, but he tended to do that from time to time, so I did not pay much attention. All that remained of the stone igloo the three explorers had built was a low, square-shaped wall of rocks. It was humbling to think of the conditions those three men had endured, just to collect a few emperor penguin eggs. We all spoke in hushed voices, as if we were on hallowed ground, and in a sense we were. After we took off again, the pilot flew us up and over the summit of Mount Terror. Below us lay Cape Crozier, with both the Adélie and emperor penguin colonies in view. Beyond that and extending as far as I could see was, in my opinion, one of the seven natural wonders of the world: the northern edge of Ross Ice Shelf. The shelf ends abruptly in a 30-to-50-meter-high cliff face, a sharp, white line that cuts cleanly through the blue-black waters of the Ross Sea. No scene on the planet is more dramatic. Once we returned to McMurdo, I learned that Walt had broken his collarbone on the fall and was in intense pain. The pilot’s broken nose, too, was more serious than anyone had thought; the base of his brain case was actually leaking, and he ended up spending several days in the clinic. As I’ve said before, penguin research is dangerous. Nonetheless, from a scientific standpoint, that short trip had been a big success. From those five recovered capillary tubes, I learned that one of the penguins had dived to 265 meters. That depth was greater than anyone would have guessed a bird might be capable of attaining. Plus, it was very significant in such a small sample size. It was like randomly sampling five athletes on a bus and discovering the tallest was seven feet high. It would be reasonable to conclude you were among a group of basketball players. That deep-dive record for a bird held for sixteen years, until it was broken by a king penguin diving to 280 meters during my work at Saint Andrews Bay in February 1985. Now at Cape Washington, I suspected the king penguin record would be broken by an emperor. I couldn’t wait to start getting deployed TDRs back. Of course, first we had to get them on the birds. In doing so, we tried to be as gentle as possible. The idea was to use a shepherd’s hook to snag the neck of an emperor heading to the ice edge, then hug its flippers against its sides until we could get a dark bag over its head. When it could no longer see, it would calm down. Easier said than done. We wore goggles to protect our eyes from the bird’s sharp beak, but an emperor’s flippers are like solid steel when they’re flailing around and all of us took a beating at one time or another. Once the

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bird was restrained, we’d attach a TDR to its feathers with glue and plastic cable ties, then let the bird resume its journey to the sea. We always placed the TDR on the lower back, as it was less likely there to impede the laminar flow of water over the bird and impact its swimming speed. The last thing I wanted to do was make the bird an easy target for leopard seals. Interlaced with the work of capturing and weighing penguins, attaching TDRs, and then waiting for their return, we had constant camp duties in this trying environment. We had to dig out after snowstorms, melt snow for drinks and food, and maintain the fence around our frozen water supply. The birds were constantly trying to mess with the fence and contaminate that one clean patch of snow. At least they were entertaining to watch, though that presented its own challenges. Here we were, surrounded by one of the most spectacular birds of all time, and there were no windows in our WeatherPort or Scott tents! To observe from the comforts of a warm enclosure, we had to open the door, or at least turn down a flap of the fabric door, and soon the shelter was not so warm. So most of our observational time was when we were outside. We began to get a sense of the birds’ character. If we remained still, they would approach to within a meter, but any sudden move sent them scurrying. Ropes were a mystery to them. They were either pecking at them or doing a Charlie Chaplin routine whenever a foot got caught in a tent holdfast. Some of the boldest would approach an extended hand and cautiously nibble or grasp it for a moment with their beaks. It reminded me of the big deal made when a gorilla first touched Dian Fossey. Sleeping was a challenge, especially at first. I was awakened at all hours by the sound of penguins shuffling around my tent. Sometimes one of them would trip over a guy line and nearly fall on me. Other times, a bird would wake me by trumpeting loudly nearby. It was a sound unlike any other in the world, sort of a cross between an approaching train and an out-of-tune saxophone. When the sun was at the right angle, their shadows marched across the tent’s yellow fabric like some sort of avian puppet theater. One of the most interesting groups of birds was what we called the satellite colony. It could also be called the “newlywed” or “honeymoon” group. It was only 200 meters from our camp, separated by a kilometer from the main colony, and it was moving deeper into the bay faster than the main colony, which at this time was dividing into separate groups. Soon there would be fifteen to twenty of these “suburbs” fanning out from the core of the colony. When we first arrived, the satellite colony contained about 1,500 chicks, but to our dismay the chicks were dying fast. As the group moved into the bay, it left a trail of dead chicks, those too weak to follow. Within the group

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there were many more adults than chicks, which was the reverse of the main colony. Unfortunately, this did not bode well for the surviving chicks. The many unoccupied adults were driven to nurture a chick, so any chick left alone even for a few moments was at risk of several adults pursuing it. In their frantic efforts to take charge and brood, the adults roughed up the chick like linebackers going after a fumbled football. Since the chicks weighed only about three kilograms at this point and the adults weighed about 25 kilograms (an 8:1 ratio), this was about the same as several 200-kilogram sumo wrestlers pouncing on a 24-kilogram fourth grader. If the chick survived the scrum and was scooped up by an adult, it might be brooded for a short time. The adult might even try to feed it, but if it wasn’t one of the parents it would soon abandon the chick, and the pursuit would start all over again. By the end of the season, the satellite colony had all but disappeared, mostly a result of chick mortality rather than fledging. Next year, these “newlyweds” would probably join the main groups of penguins, though most likely not with the same partner. Meanwhile, the main colony was also expanding like a star exploding in slow motion. Those next to the cape did not move far because of the land boundary. Those with no restrictions spread out into the bay, and by December some of the groups were six kilometers from the original incubation patch. The advantage to this movement, and perhaps the reason for it, was access to whiter pastures of snow where there was no guano contamination. This saved the chicks from having their down soiled, and it gave them fresh snow to eat, which was a common activity when they were not being fed by adults. Indeed, snow was an important resource for both chicks and adults. Build a snow pile and they will come. Any nearby drifts of snow created by the wind would attract the birds, and they were commonly lined up along a ridge of snow like sports fans at a bar on game night. They particularly loved our ice-block outhouse. Over the course of our stay, the adults completely pecked it apart. Despite the erosion of our little building, it was pleasant to know that we could always count on company when nature called. What a scene to regale someone doing their business: majestic mountains, frozen seas, and emperors all around. During our vigil waiting for birds to return with data, we spent time inspecting the ice edge, and on November 13 I observed my first leopard seal kill. Several emperors were trapped on an ice floe next to the edge. The seal circled the floe several times, agitating the birds, then it rose out of the water and made a rush onto the ice. The emperors scattered to the opposite side and escaped into the water—all but one. That unfortunate bird was trapped against a small wall of ice, and the seal struck. It grabbed the

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bird’s torso with its Tyrannosaurus-like jaws and disappeared with it into the water. If this had been an Adélie penguin caught by the seal, which I have seen many times, it would have been eaten at the surface. Before each mouthful the seal would sling it back and forth, stripping the skin and feathers from the carcass. In all my observations of emperor penguin kills, the actual consumption was usually out of sight, and the seal never flung the bird back and forth. Perhaps emperor penguins are too big and heavy to be flayed effectively. On November 27, Thanksgiving Day, I was becoming discouraged about my data collection. As with the king penguins on South Georgia Island, I was working with new, miniaturized electronic technology. The design modifications I had made to that earlier generation of TDRs were resulting in many system failures, and it was trying my patience, just as it did at Saint Andrews Bay. My team and I were also working out the best way to deploy TDRs on emperor penguins, and we were suffering numerous losses. It turned out that the plastic cable ties we used sometimes snapped in the cold, and they didn’t hold the TDRs as snugly as I wanted. While waiting for TDRs to return, I tried to reassure myself by imagining the birds were just staying out longer than we expected and would eventually come back with my instruments. Even though our pick-up date was closing in, I held out hope that we would recover some of those missing TDRs. Finally, fortune smiled on me. We began to recover TDRs that had worked properly, and the data they held was spectacular! I had been right about emperors breaking the king penguin record—the TDRs had recorded numerous dives in excess of 400 meters! That was just astounding for a bird, and I suspected they were capable of deeper. The emperors were giving the Weddell seals, which were ten times larger, a run for their money. The weather had become surprisingly mild. I had anticipated miserably cold and windy conditions, like at Cape Crozier, but our days at Cape Washington were generally sunny and warm (for Antarctica), with little wind. I concluded that in selecting breeding sites, the birds knew what they were doing. Too bad the Northern Party did not know about this place, as they would have been much more comfortable than they were at Inexpressible Island. Also, we had experienced no injuries, and the living conditions were excellent. We spent more and more time at the ice edge in the hope of spotting a returning bird with a recorder, as well as to observe the comings and goings of the birds in general.

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The predatory activity of the leopard seal was as enthralling as a good horror movie, and the capture scenes were gripping. Passing killer whales became more frequent and more numerous. On November 30, we conducted a chick census by dividing up the colony, which had separated into seventeen discrete groups, and working in pairs to count our designated groups. There were more than seventeen thousand chicks, far more than what I had estimated based on a 1983 aerial photograph. It was the second highest count for any known emperor penguin colony. However, over the course of the season, and now especially, we noted that there were hundreds if not thousands of dead chicks. I wondered, was this normal? Over the ensuing years, I learned that nothing is “normal” in an emperor penguin colony. By now, each of us had found our way of doing things. As a group, we did things collectively only when it was necessary. Otherwise we worked individually. My team had turned out to be the most independent, maverickoriented group I had ever worked with. Real individualists, all three of them. I couldn’t tell them anything. I tried to control them, but it was like herding cats—graduate student cats, in this case. I’ll freely admit, it annoyed me at times. At one point, we decided to climb Cape Washington as a group, and I knew (or thought) that we would be the first people to ever do that. As we approached, I saw ski tracks on the snow. When I asked who had come this way, all I heard was, “Oh, I didn’t do that!” “Well, then, where did these tracks come from?” The answer was a lot of hemming and hawing and shrugging of shoulders, but sure enough, when we got to the top of the cape there were footprints all over the place! “All right,” I said. “Who did it?!” Don finally admitted that he was the culprit. He wanted to be the first person to climb the cape, and so he is. Eventually, I had to sit them all down and give them a talk. I told them that Dave Bresnahan, the NSF representative who had always supported my work, had gone out on a limb to get my project approved. The NSF was generally reluctant to deploy biologists to deep-field camps (unlike glaciologists, who did it all the time). More to the point, mine was the first-ever remote, long-term camp on sea ice. The NSF had never wanted to do it before, because if the ice broke up the team was a long way from help and had a real problem. “There are a lot of eyes watching us,” I said. “If we screw up and someone gets hurt and we have to have an air evacuation, it’s not going to be

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that they just come and get the injured person. They’ll close the camp. They’ll come and take us all in. My whole project, my dream here, will be blown up.” Things were better after that. Still, Steve gave me a written summary of how he felt about me. Mainly he was nursing a bruised ego. He considered himself the head mountaineering advisor, but I treated his advice as just that, advice, and not orders. His irritation went all the way back to the traverse, when we did some of the travel his way and some of it my way. Once we got to the sea ice, where I had decades of experience and he had none, we pretty much did things my way. I don’t think he took it well. Sheridan tended to work during hours that enabled him to avoid both Steve and myself. He was a mellow person, as demonstrated by his response after nailing his finger to a box lid while closing it. So much for no injuries. Although he was surrounded by the rest of us, he never uttered an “ouch” or even a word asking for help in extracting the nail. He reminded me of Phil Thorson, the taciturn Swede of Saint Andrews Bay. On December 4, we deployed the last TDR, and in the process I hurt my back. I was still mobile, but not so lively about it. The next day, while at the ice edge doing observations, I moved too close to the edge and a leopard seal came charging out of the water after me. I tweaked my back again executing a rather ungraceful maneuver to avoid being bitten. Four days later, on low, flat ice, another seal (or perhaps the same one) came after me. This time my curiosity was whetted and I wanted to see just how far the seal would go. I could do this with impunity because leopard seals are very slow on ice. Despite their very long fore flippers, they do not use them when crawling. Instead, they move like an inchworm, but without the back flexibility of the worm. So I waited until the seal came to within a meter, then I moved back two meters. The seal kept coming, and I kept moving back, just enough to stay out of reach. The dance continued until I had moved back about 70 meters from the edge, at which time the seal gave up and turned back toward the water. In a stroke of fortune for the seal, a group of birds arrived just then, vaulting out of the water to land on their bellies and scoot across the ice. The seal grabbed one as it slid past. The bird went completely limp. There was no struggle at all as the seal carried it to the edge and disappeared underwater. This was a new observation and very interesting to me. On December 8, we observed two chicks at the edge. On the 9th, there were six, and by the 15th, hundreds. Surprisingly, they were departing the breeding ground while still wearing about 60% of their down. Until we saw

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this, it was generally believed that the chicks simply floated away as the sea ice broke up at the end of summer. It was not lost on me that my team and I were the first people ever to observe these natural phenomena: the down-covered chicks actively leaving the colony and heading to sea; the hunting activities of the leopard seal; and the behavior of killer whales and other cetaceans at the ice edge. I was again thankful that the NSF had allowed me to establish a remote, fullseason camp on annual sea ice, and I was taking full advantage. By now, the original incubation area of the colony was blackened from guano stain. Because no snowfall had covered it, it had melted into a dark cesspool that formed a barrier, for both us researchers as well as the birds trying to access the ice edge. Every single guano stain eroded into a pit from a few centimeters to half a meter deep. Our beautiful, smooth snowfield looked like a battlefield after days of shelling and bombing. It was almost impassable by either snowmobile or skis. We began taking a long detour around the center of the colony, as did the penguins if they could. Each group of penguins moving farther into the bay migrated from a deeply pitted area to a clean snow area, which lasted only a few days before it was pockmarked as well. Our camp also showed the ravages of our activity, as well as that of hundreds of penguins marching through on their way to the suburbs beyond. Our freezer dug into the snow was now full of seawater. The sea ice had become porous. Weddell seals hauled out all around us, within 50 meters of camp, which meant there were holes there big enough for them to fit through, and big enough for a human to take an unwanted swim. The entire area under the snow was flooded by seawater. Everywhere we walked, the crust would break and we would sink to the surface of the sea ice. It was time for us to move farther away from the cape, where there was less of a snow burden depressing the ice, and consequently less flooding. After moving our tent and other camp paraphernalia, we lifted the WeatherPort onto Nansen sleds and towed it to our new campsite with the snowmobiles. Once again, we were high and dry, but for how long? Scattered throughout the area were slumps in the snow surface. These slumps were to be avoided, whether on skis or snowmobile, because there was no ice under them. It had eroded away, and all that stood between us and the frigid ocean was a snow layer that had not melted. They were like giant, camouflaged water traps, and the consequences would be grim if we drove or walked into one. There were other changes in our camp as well. Adult emperor penguins no longer came to visit. Instead, when we went to bed now it was

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to the haunting sounds of leopard seals vocalizing in the water below us. How many souls have been serenaded to sleep by the sotto voce codas of leopard seals? On December 17, a Finnish ship passed by. It was somehow reassuring to see this first sign of humans in almost three months. We learned later that the ship had been contracted by the Italians to carry material they needed to build a research station next to Gerlache Inlet, on the other side of the Campbell Glacier Tongue, just a few kilometers from our Cape Washington camp. With ice conditions as they were and the glacier tongue projecting into open water, that new base may as well have been on the moon as far as we were concerned. A few days later, we spotted a Twin Otter aircraft on the sea ice near the bay’s north cliff face. It was a few kilometers away from where we were and took off before we could approach. That got me to thinking. An aircraft that could land on sea ice without prior coring could be very useful for the research I planned to do, for I was quite determined by now that this would not be my last time at Cape Washington. Not long after, two New Zealand helicopters dropped in. Like the Finnish ship, they had been contracted by the Italian expedition. The pilots told us the Twin Otter was part of a Norwegian expedition and was heading back to New Zealand. That was 3,500 kilometers away! The plane must have been a flying gas tank. No wonder it seemed to struggle to get into the air. By December 22, there were hundreds of chicks at the edge preparing to leave, with more on their way. As small groups trundled toward the edge, they uttered a distinct call that seemed to attract other chicks in a pied piper effect. By the time the group reached the edge there could be a line two hundred chicks long, extending from the edge to 300 meters into the bay. It reminded me of the movies I had seen of caribou in the Arctic and wildebeest on the Serengeti. At the edge, we could see fifty to a hundred killer whales passing by, heading west where the ice edge dipped deeper into the bay. My guess was that they were after the big toothfish taking refuge under the fast ice of Terra Nova Bay. On the 23rd, I saw a leopard seal take an emperor chick while swimming alongside the killer whales. This lack of concern on the part of the leopard seal suggested to me that it could discriminate between fish-eating and mammal-eating killer whales. All in all, the ice edge had really become lively, and it was with some reluctance that we accepted an invitation to a Christmas party on the Finnish ship anchored on the other side of the bay. Who would have guessed that

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we would have a social calendar in this remote camp? So we disengaged ourselves from the cape for a day. The Italian leader greeted us upon landing and let us know our rooms were ready. This came as a bit of a surprise. Instead of hosting us for a short visit and a meal, as I had expected, he had planned on us staying overnight. My teammates were placed in the ship’s infirmary, while I was put up in a cabin with the expedition’s military liaison. They also gave us two big treats: a nice shower (our first in months) and a call home on the ship’s radio. Even though every sentence had to end with “over” so the radio operator knew when to switch to the other party (this was the dark ages of communication, after all), it was still uplifting to speak to loved ones after such a long absence. When we finally made it to the lounge where everyone was gathered, alcohol was flowing freely. It was quite the international gathering. The New Zealand pilots said little, the Norwegian mountain guides spoke of their frustration with Italian field planning, and the Finns told us of their frustration with the way the ship was being used. The Italians, on the other hand, were having a grand time. Everyone seemed pleased to speak to us, I suppose because we were the new faces in the crowd. Finally, the ship’s captain and his wife invited us to their room, where we talked until early morning. Christmas dinner was a substantial buffet at 11 a.m., which appeared to be much too early for many people. Perhaps they were still recovering from the alcohol the night before. An early multicourse meal, one not prepared on a camp stove after a long day, suited us just fine. It also seemed to suit the Kiwi helicopter pilot, who flew us back to our camp at 1:30 p.m. We were anxious to return. So much was happening at the ice edge, and the camp needed tending all the time because of the rapidly eroding ice. On the way, the pilot took us along our traverse route over the Campbell Glacier Tongue. I was dismayed to see large crevasses everywhere along our route, and I understood why the scientists who had worked on Mount Melbourne were pessimistic about my proposed crossing. It would have been like crossing the Golden Gate Bridge before they covered the girders with a road. Had I known it was so bad, I might not have attempted it. We also flew over the dispersed colony and got a good look at all the groups and where they were located. It reminded me of human suburbs. As cities become more crowded, people move out and trash the surrounding wilderness. A quick check of the ice edge seemed to indicate that the mass chick exodus was over, with only a few stragglers waiting to go to sea. It was a disappointment to me that we seemed to have missed it. The next day, I was pleased to see there was still a lot going on at the

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edge. Hundreds of chicks were still moving out, but it was also depressing to see that many of them were dying on the ice. They had been without a meal for too long before attempting to depart. No doubt their parents had left to feed up for their molt. The ice situation had become more dynamic, and we had to remain alert. There was a swell running, and the edge was undulating so much that looking west along the edge nearly made me seasick. By December 28, much of the ice was breaking out, including the incubation area. At least the cesspool was disappearing, but so was our access to the cape. There were cracks everywhere. Several times we crossed snow in which our tracks turned to slush. Had we not kept our speed up, the snowmobile would have sunk. The last day of the month was hot, and the sun was making it a race between the sea ice and the icebreaker as to whether we would be here to meet the ship or swimming with the penguins, seals, and killer whales. Chicks were still departing in fair numbers, but there was more time between departures than earlier in the month. While waiting at the edge for a group to plunge in, I relaxed on a large ice block. It was comfortable and afforded an excellent view over the ice edge to the water. Then a leopard seal slithered out of the water and up to my ice chair, fixing me with a direct stare. This got my attention. I took a quick photo then jumped off the back when it looked like he was going to come up onto my spot. On the 31st, Don cooked an excellent turkey meal. It took some time on our little two-burner stove. While he worked at it, I relaxed at the ice edge, admiring the mirror images in the channels, especially when a group of chicks swam by in search of a channel that would lead to open sea. The ice floes formed a difficult maze for them. I tore myself away to go back to the hut for dinner. Afterward, we reminisced about past New Year’s Eves. For all of us, this must have been the most memorable, and we sealed that possibility by going to the ice edge for a toast. It was clear and calm. An Adélie penguin joined us for a while, becoming especially curious when a few of us stood on our heads. Back at camp, I finished a draft paper about Cape Washington and then skied back to the ice edge for a few hours. It was hot, and about fifty chicks had worked their way onto some floes. In a short time, a leopard seal took two of them. When I returned to camp, the others left to climb Cape Washington the hard way, by scaling the face of the ice cliff and ascending to the top. While they were gone, I adopted an emaciated chick that had collapsed almost at our door. I wanted to see if it was possible to get a bird feeding on our canned fish. It was. I also checked out the campsite for any new

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sinkholes. There were now three close to camp, and I wondered if any were developing under the tents or hut. It was a mystery how they formed, but erosion under the ice was not surprising to me because I had seen similar conditions in McMurdo Sound. In those cases, holes occurred where the water became shallow near a point of land and currents were consistently strong. Something similar could be happening here, though the bottom topography of the bay was unknown. The next day, my little friend had company, and I fed them both at frequent intervals when I was in camp. At the ice edge, Don saw killer whales spy-hopping near a group of penguins. One of the whales nudged a swimming chick, but otherwise they ignored the chicks that were setting off on their journey to unknown places. The edge was turning into whale city, with twenty-five to fifty killer whales routinely swimming in to or out of Terra Nova Bay. In addition, minke whales arrived to make perpendicular transects under the ice. We lined up at the estimated place they would sound to watch them dive below our feet. Sweet! On January 4, we received a radio message that the icebreaker was 640 kilometers away and expected to arrive for boarding at 6 p.m. on the 6th. Our time on the ice was coming to an end. I had already begun to write a grant renewal. I knew I had to return to Cape Washington. The enchanting hook of the emperor penguin was anchored deeply. The ship arrived at 6 a.m., twelve hours early. Not that I minded, but it was a bit of a flail to give a last meal to the chicks then leave with Sheridan to retrieve our specimens cached up on the glacier. While we were gone, a Coast Guard helicopter took Don and Steve to the ship, along with all their personal gear. When Sheridan and I returned, the sky was threatening and we were told to get on the helicopter and leave everything. No way! On the ship I had a somewhat strained conversation with the ship’s officers, and they agreed to fly us back to the camp and retrieve all the camp gear, including the snowmobile and sleds. For a while, the bay was abuzz with helicopters flying back and forth. At one point, I saw killer whales diving under the ice nearby, with twenty to thirty skuas swooping down, picking something off the water, and taking it over to the ice. I wanted to head over and see what it was but never got the chance. Before long the icebreaker was underway and Cape Washington was disappearing astern. It was a bittersweet moment. I was happy to be going home to see my family again, but it was sad to leave such a magical place. Back in McMurdo, I debriefed with the NSF operations manager and planted a seed regarding Twin Otters. They can fly over open water and land on sea ice without previous coring for thickness, and the pilots are pri-

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marily bush pilots with thousands of hours of experience. The NSF should buy one, I told him. It would be the most useful aircraft in their fleet. On the long flight north to Christchurch, New Zealand, I had plenty of time to reflect on my time at Cape Washington. With all that could have gone wrong on the expedition, none of it did. I couldn’t help but feel I’d had beginner’s luck. Sure, there were some failures. The electronic TDR technology was still in its infancy. We lost some recorders and others failed, resulting in a lot of lost data. Nonetheless, I established the duration of the birds’ foraging cycles and proved that I could recover TDRs successfully in such a large colony. More important, I discovered that emperors made many dives greater than 400 meters, proving they were the supreme divers among birds. Equally important, I established that my team could work from a field camp on sea ice for an extended period of time, and that Cape Washington was probably the best possible place for my research. I envisioned an exciting future.

[ Ch a pter 5 ]

Kings and Emperors in One Year

To strive, to seek, to find, and not to yield. A l fr ed, Lo r d Tenn yson

The three years following my Cape Washington expedition were a flurry of activity. In 1987 and again in 1988, I returned to McMurdo Station to conduct physiological studies on both emperor penguins and Weddell seals from a camp on the McMurdo Sound sea ice. My team included graduate students, postdoctoral researchers, and technicians. I was also joined by a new colleague, Dr. Paul Ponganis, a medical doctor/anesthesiologist with a keen interest in animal diving physiology. We were interested in determining how both animals managed their oxygen stores. How were they able to make so many dives in rapid succession with such short surface intervals? How were they able to dive so deep and hold their breath so long? The Weddell seal work was a follow-up to research I had begun in the mid-1960s, whereas the emperor penguin work was relatively new. In both cases, I used the isolated hole protocol I had developed years earlier. This involves cutting a hole at an isolated location in the sea ice, far from any other hole or naturally occurring crack, which is something that can be done only on the fast ice of McMurdo Sound. (Fortunately for my 1980s work, the Antarctic support contractor now had a mobile drill that could punch a 1.2-meter hole through the sea ice in a matter of minutes, a vast improvement over the 1960s multiday process of using chain saws.) Once we brought a seal or penguin to this hole, they must use it to breathe, making them a captive hunter, so to speak, though they could still dive and forage as they normally would. The situation made it a simple matter (relatively speaking) to attach and recover instruments, take measurements, and collect samples for analysis. The seals were easy to come by, as they were scattered all over the sound. For the penguins, my team and I traveled to the ice edge, where we

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Figure 5.1. The 1989 Cape Washington team standing on Observation Hill, next to the cross erected in memory of Robert F. Scott’s last expedition. From left to right: Markus Horning, Carsten Kooyman, Jerry Kooyman, and Scott Eckert.

could almost always find emperors. Even if there weren’t any immediately visible when we arrived, it wasn’t long before they appeared, attracted as they always were by upright objects on the ice. First we’d see them popping their heads up out of the water to eye us. Before long, they’d slide out of the water onto their bellies, use their beaks to push themselves upright, and saunter over to check us out. It was a simple matter to capture a few and transport them back to the sea-ice camp we had set up for our research. As emperors tend to wander far and wide, some of them even walked to the camp on their own, several miles from the ice edge, and we gladly made them experimental subjects. Human visitors to the camp, with its ten or so penguins clustered around a dive hole and surrounded by a fence to keep them from wandering off, began calling it the Penguin Ranch, and the name stuck (figure 5.2).

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Our work added weight to a concept I had developed in my previous work with the seals: the aerobic dive limit (ADL). I had noticed that most Weddell seal dives were about twenty minutes long, and that there was usually only a short surface interval between them. I had postulated that they held enough oxygen in the hemoglobin and in the oxygen-rich myoglobin contained in their muscles that, when combined with shunting blood flow away from everything except the brain and heart during a dive, allowed them to dive to that limit without incurring what is often referred to as an “oxygen debt.” If they went beyond that time limit, they would have to transition to anerobic metabolism, which created lactic acid that would then have to be converted back to glucose by the addition of oxygen. That is the oxygen debt, and it would take longer at the surface to repay it. I strongly suspected all diving animals had an ADL, and I was interested what it was for the penguins. The Penguin Ranch work would lay the groundwork, but what I also needed was a lot more dive records. Fortunately, there were three other significant developments during these two years. First, following my suggestion, the NSF contracted a Twin Otter aircraft in 1988 to support scientific research. This would prove to be enormously beneficial to my later work at all the Ross Sea emperor colonies, especially Cape Washington. Second, in 1988 the NSF/OPP honored me with a Creative Scientist Grant, and it came with enough funding to support two more full seasons at Cape Washington. It was better than winning the lottery! I immediately set to work writing a multiyear proposal. Third, my friend Yvon Le Maho, the head of the polar bird program at

Figure 5.2. The Penguin Ranch, on the McMurdo Sound sea ice. (Photo by P. Ponganis.)

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the French National Centre for Scientific Research (CNRS), secured an invitation for me to work with king penguins at the Alfred Faure Research Station on Possession Island, in the sub-Antarctic Crozet Archipelago. The very limited data I had collected at Saint Andrews Bay dissatisfied me. Working from an established base like Alfred Faure would afford me the opportunity to assemble a more complete picture of king foraging behavior and diving ability so I could better compare them with their larger cousins. In addition, I now had much-improved TDRs, and I was confident they would produce better data. New Year’s Day 1989 found me, my son Carsten, and one of my graduate students on a plane from Paris to Réunion Island, 680 kilometers east of Madagascar in the Indian Ocean. Once there, we met the French biologist Yves Cherel, a new PhD from Le Maho’s lab and an experienced investigator of king penguins. He would act as a translator for us, as well as assist me with my research. The four of us boarded the French research vessel Marion Dufresnes for the 2,834-kilometer voyage to Possession Island (figure 5.3). Working on Possession Island was very different from what Phil Thorson and I had experienced on South Georgia. The isolation and quiet at Saint Andrews Bay was wonderful, but there was something to be said for coming back from a day in the field to a hot shower, a prepared meal, and a warm bed. Every day was another experience with gourmet French cuisine. They brought in a whole cow carcass at one point and used every part of it. After making oxtail soup, the cook served up a dish of brain. I turned to Carsten and said, “You know, they’re going through the whole cow, and this is the end of it.” Everyone was watching us when the brain was served, but we declined to eat it. In addition to my aversion to organ meat, I was by that time on my way to becoming a facultative vegetarian. Of course, the French could serve cardboard and it would be delicious because the sauces are so good. The best thing about the island, though, was the wildlife. The Crozet Archipelago is a magnificent place, especially for ornithologists; it has more species and higher populations of seabirds than anywhere else in the world. However, most of my attention was on the king penguin colony at Possession Bay, which had sixty thousand breeding pairs and was readily accessible from the base (plate 7). My team and I attached the new TDRs to ten birds and obtained a much more complete picture of king penguin foraging habits (figure 5.4) than was possible during my Saint Andrews Bay work four years earlier. Our records showed that the penguins’ favored diving depth during daylight hours was between 150 and 250 meters. At night they continued to be active but only diving to very shallow depths, with little resting. The

Figure 5.3. The location of the Crozet Archipelago in the South Indian Ocean, with the bathymetry around Possession and East Islands. (Chart modified from Kooyman, Cherel, et al., “Diving Behavior and Energetics.”)

Figure 5.4. A complete, seven-day dive record of a king penguin foraging trip.

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deepest dive we saw was 304 meters, which remained a king penguin record for several years, until another researcher measured a 340-meter dive on a king from the Falkland Islands. We knew that the king’s preferred prey was the lantern fish, one of the most widespread and abundant fish in the Southern Ocean. These fish are diurnal migrators, resting torpid at depth during the day and rising to near the surface at night. I had assumed that the birds feed on these fish as they migrate to the surface, but Le Maho and others later demonstrated from stomach-temperature measurements that the main feeding time is during the day. The fish are highly bioluminescent, so it makes sense that they would be visible to the penguins, even in the darkness at depth. Nonetheless, why the penguins’ preferred capture depth of these vertical migrators is in the daytime when they are so deep is still a mystery to me. Perhaps it’s because the fish are torpid at that time and easier to catch. Other studies by French biologists showed that the penguins traveled to the Antarctic Polar Front (also called the Antarctic Convergence), which was usually about 300 kilometers south of the colony and always in very deep water. Because the birds traveled so far from their colony, it was a mystery how they would be able to return without digesting much of the fish they held in their stomachs. Le Maho and his collaborators solved the puzzle when they discovered that king penguins secrete an antimicrobial enzyme called spheniscin from the stomach wall. This enzyme suppresses digestion during the return trip, as well as during the weeks-long fast the birds endures while tending the egg or chick. It is a remarkable adaptation. As far as I know, the king is the only penguin that secretes this enzyme, but that may be because to my knowledge no one has ever looked for it in other species. The splendid dive records we obtained at Possession Island proved that the TDRs I used were of exceptional quality and would be ideal for my work with emperor penguins. I did make one modification after returning to my laboratory at Scripps: I extended the depth range to accommodate the likelihood that emperor penguins would dive deeper than kings. I also began planning my travel to Cape Washington. Ever since my 1986 expedition, I had been thinking there must be a better way to get there than traversing the Campbell. I felt as though I had been lucky that first time, and I didn’t want to push it. I figured if we could get helicopters to fly up from McMurdo and meet us at the Priestley Glacier when the LC-130 landed, they could ferry us to the airdrop site at Markham Island, bypassing the Campbell altogether. In early summer 1989, the NSF hosted a logistics planning meeting at the Port Hueneme naval base in California, home to the Antarctic Develop-

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ment Squadron 6 (VXE-6) that flew the ski-equipped LC-130 Hercules and helicopter aircraft in support of the Antarctic Program. I was invited since I had one of the most complex field seasons for that year. To avoid the congestion of Los Angeles traffic, Carsten and I rented a plane and flew north from San Diego to Oxnard Airport, just north of Los Angeles and about three miles from Port Hueneme. With high hopes, Carsten and I walked through the administration building to the conference room. Dave Bresnahan greeted us at the door and dropped a bombshell, telling us the navy could not provide the helicopter support I requested. I was shaken, but determined not to give up hope. The representative for helicopter flight operations was Lieutenant Commander “Beez” Bohner. I knew Beez well from previous expeditions where he had flown for us. He was big, good looking, and confident, like someone straight out of Hollywood central casting. He jumped right in. “Jerry, I’m sorry, we can’t get the helicopters up to Priestley Glacier to move you from there to Markham Island.” “Why not?” Beez seemed nonplussed. Officers are not usually questioned about their decisions, but as a civilian, I reckoned I could do that. “Well,” he replied, “it’s not within the designated range of our helicopters.” “What is the designated range?” I asked. After his answer, I suggested ways to get around this maximum range. For example, they could cache fuel ahead of time at the site where our supplies were airdropped. I realized if I was going to win this argument, I had to keep him talking. Beez was affable enough, and I knew he saw himself as a hot pilot (and indeed, he was) who enjoyed a challenge. For every objection he gave, I offered a way around it. Finally, I said, “You know, the pilots for New Zealand Helicopters fly from the Italian base, which is a short distance from Markham Island, all the way to McMurdo Station, and they do it with smaller helicopters.” That challenge to navy pride seemed to do it. “Yeah, we can do it,” Beez said. “Piece of cake!” Everyone was enthusiastic about the plan, including the LC-130 crew and Dave Bresnahan. Other matters about my project at Cape Washington were quickly resolved, and Carsten and I left the meeting full of almost inexpressible joy. “We’re not traversing the Campbell!” I said to him. “Hurray!” With a glacial traverse out of the picture, I was not required to have mountaineers and could have a more diverse team. Over the years of working in remote camps, I had learned that the compatibility of the team is crucial to success. For this one, in addition to Carsten, I would have two

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postdoctoral students from my lab, Scott Eckert and Markus Horning. This was Markus’s first trip back to Antarctica since he worked for me as a nineteen-year-old student assistant on an overwinter Weddell seal project in 1981. Now he was a postgraduate in my lab, and he fit in seamlessly, as always. He is a man of many talents, with a strong background in physics and electronic design, even though his PhD was in biology. He was raised in Rome and is fluent in Italian, French, Spanish, and English, as well as his native German. Scott had recently finished his thesis studies of leatherback sea turtles. At his invitation, I had accompanied him on a few of the field trips he had conducted during his thesis work. I had brought along TDRs to attach to the turtles and found that we worked well together. Carsten, of course, had been a great help on Possession Island, and I knew he would be at Cape Washington as well. On October 5, we drove from San Diego to Los Angeles International Airport. In addition to our massive baggage, which included science equipment, we were accompanied by Paul Ponganis and Mike Castellini, who were also traveling to McMurdo to wrap up loose ends from the physiological experiments on emperors we had conducted in McMurdo Sound. On October 9, after two days in Christchurch, New Zealand, we were aboard an LC-130 and on our way to McMurdo. As always, we were jammed into canvas bench seats, as tight as sardines in a can, with all our Antarctic survival clothing either on our backs or in a bag under our seat. In this situation you hope for good adjacent seat companions, because they feel your every move and you feel theirs. Scott, the avid environmentalist, was not so lucky, as he rubbed shoulders with an Alaskan fisherman that told him he shot sea lions at every opportunity because they competed with him for salmon. (Years later, after the precipitous population decline of Steller sea lions put them on the endangered species list and resulted in extreme restrictions on the Alaska salmon fishery, I wondered about what that guy had been doing. I suspect he may have been shooting himself in the foot all the while with his clumsy attempt at population control.) I was much luckier than Scott because Carsten was sitting next to me, and it was with pride and enthusiasm that I pointed out features of the Victoria Land coast as we crossed it after 2,000 miles of overwater flying (figure 5.5). As we passed over Cape Washington, we could even see the guano stain of the colony, and I pointed out where we would most likely be camping. I could not be more full of joy than if I were showing him our new mansion in Malibu. Once we arrived at McMurdo Station, we moved quickly to collect and

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Figure 5.5. Antarctic landfall, showing the Admiralty Range from 37,000 feet.

organize all our food and field gear. Before we headed to Cape Washington, we planned on conducting dives at the ice edge in McMurdo Sound to observe penguins, as Paul and I had done the previous season. Carsten and I did our first check dive in front of the station, from a hut positioned over a hole in the two-meter-thick sea ice. This was undoubtedly the first time a father-son team had dived together in Antarctica. Unfortunately, Carsten’s regulator began free-flowing early in the dive. We were using the ancient double-hose regulators that had been used since diving began at McMurdo in the early 1960s. For decades they were the only reliable option, as singlehose regulators would always freeze up, but the age of the double-hose regulators and the paucity of repair parts were beginning to take a toll. (In 1990, a reliable, freeze-resistant single-hose regulator became available and quickly became the standard.) Paul and Carsten made the next dive, but this time Carsten’s mask leaked. We had better luck when we made another father-son dive with Weddell seals near a small island called Turtle Rock, about 15 kilometers from McMurdo Station. A few days after that, Paul and I snowmobiled toward the ice edge with all our dive gear. After going 72 kilometers north of McMurdo Station without reaching the edge, we realized it was too far away for our planned dive. Unfortunately, there was no time to try again. We needed to get to Cape Washington. On October 24, Markus, Carsten, and I departed on a LC-130 for a reconnaissance flight and supply drop in Terra Nova Bay. We had just reached Beaufort Island when an engine failed and we had to turn back. There was no danger, as the four-engine Hercules can fly on three engines, or even two, but the full complement of emergency equipment was standing by when we landed on the ice runway in front of McMurdo. I was reminded of a flight from McMurdo to Christchurch I had made the previous year, with emperor penguin chicks destined for controlled swim experiments at SIO.

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One of the wing spoilers had become stuck, making the airfoil asymmetric. It was a dangerous situation. We made an emergency landing with all the New Zealand rescue and fire trucks standing by at the edge of the runway, ready for a crash. We tried for Cape Washington again on the 27th. This time we had to act as a picket for an incoming US Air Force C-141 Starlifter flight. There were exceptional solar flares this season, and they interfered with radio communications. The picket plane flies some distance north of the station and relays radio communications between the incoming aircraft and the station. That job finished, we headed back south to Terra Nova Bay and ran into another difficulty. The katabatic winds were so strong in the bay that it took a second pass to line up properly for the airdrop. It was a bumpy approach, but the pilot skillfully held the plane on course and maintained enough stability that we were able to push our 7,500 kilograms of cargo out the back, on wooden pallets with high-velocity chutes attached, as usual. Those packages contained all our food, fuel, and shelter for the next two and a half months. The total weight was slightly more than an adult African elephant. Later, we would have to move our elephant 20 kilometers across the sea ice to our camp site at Cape Washington. The next morning, Markus and I departed under a thin overcast to drop another six bundles at Markham Island, then returned to McMurdo Sound to load the rest of our gear and the rest of the team for the put-in flight. When we took off, so did the helicopters from Marble Point, a fuel depot 74 kilometers northwest of McMurdo, on the Victoria Land coast. When we touched down on the Priestley Glacier, after three bone-jarring landing drags, the helicopters were already there. Just as in 1986, I had to relay my communications to McMurdo through South Pole Station. Within minutes of my successful radio check, the LC130 left and we began loading the helicopters. Then we ran into a hitch: the lead pilot did not want to leave two of my team at Markham Island without them establishing communications with McMurdo Station again. I told him this wasn’t necessary, and time was of the essence because the weather was beginning to look threatening. It didn’t take long for the pilot to see my logic. He did not want to get stuck here and have to camp out with us. He took off, left Carsten and Scott at Markham Island, and returned to the glacier for more cargo. It took four flights, but to my relief we finally had all our equipment in one place at Terra Nova Bay. The pilots were anxious to leave before the weather closed in, and soon we were alone. Too tired to begin unpacking the airdropped packages, we set up a Scott tent, got out of the cold and wind, and burrowed into our sleeping bags. We slept well and warm that

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night, as I had learned from the previous expedition and made sure we had more temperature-appropriate bags. The next morning, when we began unpacking the airdropped bundles, we got a lot of unpleasant surprises. In fact, I was appalled. The rationale of the packers escaped me. Instead of heavy items placed on the bottom with lighter and more fragile items on top, the reverse was true. For example, in one bundle the cookies, crackers, and cereal had been packed on the bottom, with canned goods on top. So we had undamaged canned goods but powdered cereal, cookies, and crackers. Were the packers confused about what side of the packages would land first? Or did they have a perverted sense of humor? Nevertheless, it was too exciting to be on the broad sea-ice plain covering Terra Nova Bay to let little problems like this dampen our spirits. Instead of actual Cheerios, we’d have Cheerio porridge. There was, however, one problem that was more serious. Rather than consolidating the flooring for the WeatherPort in one bundle for ease of break-out and set-up as soon as we arrived at the cape, the packers had placed pieces of it in every bundle. So we had to open every bundle to get all the flooring. Even worse, the packers had placed the flooring on the bottom, under heavier items. The flooring’s Styrofoam insulation, sandwiched between two sheets of plywood, was crushed. We now had a compressed and broken floor in need of much repair. Fortunately, Scott had been a carpenter before going to graduate school. After a quick breakfast, he and Markus set to work making repairs while Carsten and I packed sleds for the move to the Cape Washington camp site. Only three days later than when I had arrived there in 1986, Carsten and I were driving across Terra Nova Bay with two snowmobiles and heavy sled loads. The dark bulwark of Cape Washington was our landmark. As we drove toward it, the 15-kilometer-long, glacier-covered peninsula that connected it to the continent rose up before us. In its last few kilometers, it rose rapidly to the snow-shrouded summit of 2,733-meter Mount Melbourne. This was what Antarctica was all about: beautiful scenery, intense cold, crystalclear air, snow sparkling as if strewn with diamonds, and new paths to establish. The surface was rough and the going slow. All the more time to take in all we saw before us. Instead of a yellow-brick road to Oz, we were on a diamond-studded path to the cape. After selecting a camp location, dumping our cargo, and erecting the second of our two Scott tents, we left for another load. It was a very long day, but finally, at 11:30 p.m., the four of us departed Markham Island and drove northeast, away from the sunset.

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This being the polar region in the summer, the sun didn’t really set; it just dipped below the mountains to the west, and it was rising at Cape Washington when we arrived at camp a couple of hours later. Bone tired, we quickly erected the WeatherPort for a second shelter. Carsten and I slept there while Scott and Markus crashed in the Scott tent. We spent the next day, October 30, setting up camp and moving more loads from the Markham Island drop site. By the end of the day, we had moved the remaining 5,500 kilograms of material. All this gear ensured we could survive comfortably for a couple of months on the sea ice next to the colony. It was not lost on me that the emperors dwelled here without any baggage except for the three kilograms of food they brought to their chicks after each trip to sea. Our massive amount of baggage was a sharp reminder that we did not belong here, and without all of our tools and food, our survival here would be ephemeral. We completed camp set-up on the day of Halloween. Carsten and I erected our Scott tent, and we moved into this freezing sanctuary. At least we were out of the wind, and with our mummy bags stuffed into the larger, rectangular Snowy Owl sleeping bags designed for −20°C (−4°F), it was not too bad. That is, as long as we were fully clothed, including gloves, hat, and vest. However, we knew that soon it would be warmer and the gloves and vest would not be necessary. On this Halloween night, our sleep was not interrupted by any ghouls or ghosts, but we were serenaded by the far-off clamor of the colony and the steady crunch of footsteps in the snow from several hundred locals walking nearby. This was the ice music of the cape. The next day, we explored the colony. I saw the same distribution pattern I had observed in 1986, with the core of the colony near the cape, about a kilometer from the ice edge. From this core, groups were already starting to expand northwest into the interior of the bay. There were fewer abandoned eggs and dead chicks compared to 1986. It also seemed like there were more birds this year. The colony was massive, forming a highly concentrated semicircle more than a kilometer long. On November 3, four days after establishing camp, the science work began. We started deploying TDRs and weighing and measuring all the birds we captured. We worked fast so the birds only had to be restrained for a few minutes. I had gleaned some lessons from my 1986 expedition, which helped make things run more smoothly this time around. We used a small tent for the attachment process, which helped us work faster, and we kept the attachment supplies—like the glue—in a heated ice chest. Much of the procedure required bare hands by the applicator, which was usually me, so I was especially grateful for the tent.

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The next day, we took advantage of the now-twenty-four-hour sunlight and hiked to the top of the cape to get a bird’s-eye view of the colony. The climb was slow, but we set ropes to be used as handrails so later ascents could be more rapid. We saw that the ice edge was about five kilometers from our camp and two kilometers from the south side of the colony. We also saw that we would not be able to access the edge at present because there was too much rough ice in our way. On November 5 a storm kept us confined indoors. We used the time to prepare several TDRs, and the following day we were at full throttle with seven deployments. By now, every member of the team knew his task and the capture-and-attachment process was well coordinated. It reminded me of a pit crew doing a quick turnaround of a race car. In this case, though, it was not a fast car but a bird perfectly designed for a life at sea. I felt bad that we had to disrupt their perfectly fusiform and hydrodynamically clean bodies with our devices. However, the TDRs, relative to the size of the emperor, were the smallest ever placed on a bird. From a sub-ice observation chamber back in McMurdo Sound, we had observed birds swimming with TDRs and saw no disruption of the flow. We had decided to capture our birds for the day’s deployments on the eastern side of the colony, nearest to the sea. Two things in particular struck our senses as we navigated our snowmobiles around that massive conglomeration of penguins. One was the relentless roar of the colony, punctuated by the individual trumpeting of nearby birds. One would stretch its neck, raise its head, and emit that unique, otherworldly sound that only emperors make, and which would quickly dissipate into the vast openness of Antarctica. Punctuating these trumpeting calls was the constant cheeping of chicks. The second sensory assault was caused by the pungent, slightly acrid, and fishy odor of guano. The first was music to me, and the second, well, it was a reminder that I was in one of the most amazing places on the planet. It didn’t bother me a bit. At one point we discovered a dead Weddell seal lying on the ice near the cape. It was fresh, and there was not a mark on this robust-looking animal. The cause of death was a mystery, but we decided it was most likely a result of a large rock falling from the cape. There were quite a few of them lying nearby. I think the seal was hit in the chest and died of respiratory or cardiac arrest. I had wondered earlier if Weddell seals hauling out near the cape were at risk, and now I had an answer. After the long day of deployments, we had a quiet dinner and turned to some diversion for the evening, which was usually a walk to take photographs. This evening, though, I settled in to read Farley Mowat’s Sea of Slaughter (1984), which describes how humans have systematically

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exploited many large animal species, even driving some to extinction. It emphasized to me how lucky I was to be working in a place where no one had been before, where the place was pristine and the animals unaffected by humanity. As remote from the rest of the planet as emperor penguins were, I suspected that if and when we were to see a decline in their population because of exploitation or habitat decline, it would be when the story was already over for the rest of the megafauna of the planet. It was a depressing thought. By mid-November, we had experienced several storms, and there was deep snow everywhere. Fortunately we had collected most of the eggs and dead chicks before they were buried, because we needed them to estimate mortality. The closely studied colony near the French base Dumont d’Urville had a high chick-death rate, and I was curious to see how the rate at Cape Washington compared. The storms seemed to delay parents returning to feed their chicks, but afterward we saw long lines of birds returning to the colony. In one midNovember burst of returnees we recovered five recorders. I was up all night downloading the data and examining the results. I could not have been more excited than if I were a scientist at NASA looking over the first images of Mars or Jupiter sent back by a spacecraft or lander. The TDRs were routinely recording many dives in excess of 400 meters and even, astonishingly, some dives beyond 500 meters! The only other diving bird that even came close to these depths was the king penguin, but the king’s routine diving depth was still only half that of the emperors. I had been correct in assuming the emperors would dive deeper, and was glad I had extended the range of my TDRs. The question that kept running through my mind, of course, was How do they do it? What physiological adaptations allowed these birds to forage for food at these incredible depths? This was something that Paul’s and Mike’s work at the Penguin Ranch was designed to address, but I knew we would need several years of research to get the answers I wanted. On November 18, the temperature briefly dropped to −18° C (−0.4°F), which is the temperature at which the chicks form huddles (plate 8). This was always a pleasant sight, as they packed together with much pushing and shoving, either to get to the center or to get out. Wherever they huddled, they melted the snow beneath them. These “penguin puddles,” ranging from two to five meters across, were scattered throughout the colony and were one of the most visible landmarks. From the air they look like brown rosettes in the snow, and they are even visible from space. I thought it might even be possible to estimate from satellite images how cold it had been during the spring crèche by how many of these puddles were present.

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By the final week of November, all our TDR deployments were finished and we were in the recovery phase. Fortunately, the rough ice that had hindered our access to the ice edge had settled down or broken away by then, and as we transitioned into December we spent considerable time there observing the movement of penguins coming and going to broad areas of the expanded colony, as well as penguin–seal interactions. As if all that wasn’t interesting enough, killer whales were passing by daily, which was always a thrill for us. Our last major task, which we did before Christmas, was counting the chicks, which I knew would take up to two days, depending on weather conditions and how scattered the groups were. During the count, we looked at almost every bird. Markus saw a spotted adult at the edge. I wondered if it was the same one I had seen in 1986, but it left before I had the chance to see it for myself. If it was the same, it was essentially the only individually identifiable bird from one season to the next, since I elected not to band birds. It was amazing to me that the birds seemed to be able to tell each other apart, at least when it came to locating their mates and chicks in a colony of tens of thousands, when to us humans they looked identical. Just as in 1986, there was so much going on with the animals at this time of year, it was with some reluctance that we accepted an invitation to spend Christmas Day at the Italian station. It was a very magnanimous gesture, though, and it would have been bad form to turn it down. Plus, I had another reason to accept. At 10 a.m., a pilot picked us up and flew us along the ice edge to the base. What a view! Killer whales were working the edge, diving deep beneath the ice to hunt Antarctic toothfish, which can be two meters long and weigh up to 100 kilograms. They are a very oily fish, which makes for a calorie-rich meal. At one time or another, I had seen both whales and Weddell seals come up with one of these big fish in their mouths. When we arrived at the almost-new Terra Nova Bay base, Mario Zucchelli, the base commander, greeted us and immediately tried to strike up a conversation in Italian with Scott Eckert. Mario had been told one of our team had been raised in Rome and immediately assumed it was the darkhaired Scott. He was surprised when the blond, light-complexioned, multilingual Markus interceded to help out the confused Scott. Mario showed us around their new base, which had been built with the highest environmental standards in mind. Ever since a Greenpeace expedition had spent a year in Antarctica, raising concerns about how the US and others were handling waste, there was a new ethic in the land. It was long overdue. After the tour, I paid a visit to the doctor. A few days earlier, I had been

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eating raisin bran cereal that had been frozen for years. The raisins were rock hard, and when I bit down I sheared off a large section of a molar. It wasn’t painful, but my tongue kept seeking out the hole, which felt like a canyon through my tooth. The base doctor was the substitute dentist. Not so good, but better than the other way around, I figured. In any case, after examining me he decided he should drill the tooth and place a temporary filling. He then pulled out a small, fold-up drill kit, blew off the dust, and began to read the instructions. I was not reassured. It was certainly not my ideal Christmas Day, preparing to have dental work done for the first time in forty years, and by an amateur with rudimentary equipment. After reading the instructions, the doctor looked me in the eye and said in a very serious, Italian-accented voice, “This is going to be very painful.” He had my full attention there. Soon after he began to drill, I smelled burning bone. Yes, it was painful, and the process seemed interminable. Finally, he finished, and a temporary filling was in place. My only lingering pain was a whiplash-like ache in my neck, because the chair had no headrest. I thanked him and returned to the lounge, where Carsten was watching out the window as the helicopter returned from a short flight. Suddenly, the pilot appeared to execute violent maneuvers as he aimed for the helicopter pad, which was the only flat area among steep hillsides of large boulders. I wondered aloud if the pilot was showing off to his passenger. My answer came almost immediately as the plane mechanic, who was directing him to the pad, dived off the edge of the hill and took refuge behind the fuel tanks. The helicopter came down so hard that the skids broke off and the aircraft slid off the pad. After it came to a stop, several people ran to it, and the pilot and passenger stiffly clambered out. The helicopter had lost power on approach, but the pilot had done a magnificent job of maneuvering and autorotating the aircraft down onto the pad. There were no injuries, though the helicopter sustained substantial damage. While at the base, we got news of the world and were surprised to learn that the US had invaded Panama! Also, Eastern Bloc governments were falling, and the Berlin Wall had come down! It was especially interesting to get Markus’s response to that news, as he was a German citizen. As a young man, he did not expect to see such an event in his lifetime, and now it was happening while he was so far away from his home and parents. When it was time to return to camp, the chief pilot of New Zealand Helicopters loaded us into their second aircraft and asked Carsten, who was sitting in front, whether he wanted to go high or low. Carsten said low, and low it was. Nearly all the way back, including crossing the Campbell, we were only about five meters above the ground. This included a very pic-

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turesque transit through a small canyon formed by the Campbell Glacier Tongue. (From that day forward, Carsten wanted to be a helicopter pilot. Unfortunately, the cost of helicopter flight training was out of sight, so he decided to become an airline pilot instead. So much for his zoology degree, I thought, but it was his decision and I supported it.) By now several thousand chicks, on their way deeper into the bay as the colony expanded north, were trudging through our camp. We enjoyed their brief passing, but like a New York ticker-tape parade, there was a downside. Our beautifully clean snow around the camp became littered with down feathers, skin scale, and guano that never went away. The guano melted into the snow and left little craters everywhere. It was the price one paid for living with emperor penguins. As we approached the end of December, we had recovered most of the TDRs, apart from those attached to birds that never returned. Carsten made the insightful observation that long feeding cycles were only with birds that we captured in the colony rather than outside the colony and on their way to the ice edge. This suggested to me that the colony was a sanctuary for them, and that any capture we made within its boundaries was more traumatic than those we made outside. The evidence was convincing enough for me to never again make my first capture of a penguin within the colony. By New Year’s Day there were few chicks left in the colony, and the few that remained might or might not get fed. It was do or die for them now. They either left soon or wasted whatever fat reserves they had left waiting to be fed, which most likely would not happen. They looked pretty ragged, too. Adult plumage was replacing their gray down, but in this halfway state they looked like birds with a bad case of mange. With all the TDRs recovered and the chicks mostly gone, we opted to spend more time at the ice edge, where all the remaining action was. However, this was getting risky. On December 28, as we drove across some slushy snow, I was alarmed to see the lead snowmobile throw up a squirrel tail of water and snow from the tracks. Fortunately, we were going fast and turned sharply toward more solid ice. It was obviously unsafe to drive too close to the edge now. There were other risks as well. One day at the end of December, the four of us decided to go to the edge to observe the behavior of fledglings heading to sea for the first time. It was a dangerous time for those chicks and easy pickings for leopard seals. There was a likely possibility of seeing predation in action. It was an overcast day, with not much wind. Though the temperature hovered around freezing, the dry air made it seem warmer than it actu-

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ally was. Scott and I were on one snowmobile, Markus and Carsten on the other. The ice was significantly degraded, especially as we drew closer to the edge. In addition to cracks, melt pools, and slushy areas, there were spots where the ice had dissolved completely, creating a hole that went all the way through to the water. It was a reminder that the disintegrating ice was the only thing separating us from a very cold ocean. Scott and I motored to a spot about 90 meters from the edge. The sea ice beyond was riddled with disintegrating ice. It was completely unsafe for the snowmobile and unsafe even for walking, but I had spotted a bloodied chick on the sea ice near the edge, and I wanted to determine its condition. I put on skis and headed toward the chick, knowing the skis would spread my weight enough to keep me from breaking through thin ice. In retrospect, of course, I realize that the fresh blood was probably a clue that it wasn’t a good idea to go out there. But the skis were doing well on the rotten ice, so I kept going. As I crossed a crack covered with thin ice, a leopard seal broke through with a loud exhalation and rose out of the water right next to me. Startled, I fell away to my side, losing both my skis and my poles. Towering over me, the seal pivoted, looked down, and opened its massive jaws (figure 5.6). It looked like a Tyrannosaurus! I thought, This guy’s going to bite me. He’s going to grab me, and if he grabs me, I’m done. He’ll pull me right through the ice into the water. And my second thought was, This is an awful situation. My son is over there somewhere. If he sees me get killed, that would be really traumatic for him. It seemed like forever that the seal loomed over me with its gaping jaws. Without taking my eyes off it, I groped around until I felt one of my ski poles. I brought it up and began tapping the seal on its neck. I didn’t yell. I just softly said, “Go away. Go away.” Finally, the seal dropped back into the water. I got to my feet and moved away from the crack. Seconds later, it came up in another spot and looked at me, really eyeing me. I moved in a different direction, but it submerged and came up in front of me again, cutting off my escape. He was just punching through wherever he felt like it. I had seen leopard seals stalk penguins trapped on ice floes in the same way. They harry the poor penguin, herding it until it has nowhere to go. Then the seal strikes. I was that penguin. I was standing on a relatively hard spot where there was still some dry snow, but everywhere else was either thin ice, open water, holes, or slush. The only way back to safe ice was over the crack I had crossed earlier, but to cross it now would be to invite an attack from below. Even worse, the chunk of ice I was standing on wasn’t very thick. If the seal

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Figure 5.6. A leopard seal demonstrating its massive jaws.

came out to grab me, its extra weight would break the ice and send me into the water. I was trapped. Scott had moved the snowmobile about 150 meters away from the edge and was busying himself with his own skis and camera until he heard me yell for an ice axe. Seeing my predicament, he dropped his camera, grabbed an axe, and raced over. When he was about 15 meters away, I told him to stop and toss me the axe. I had the sense that I could defend myself with it. I really didn’t want to, but if the seal tried to grab me, I’d poke him in the eye. That would probably be painful enough that he would let go. That was my last resort if this went any further. The seal kept coming up, at a different spot each time, watching me, while I stood there trying to figure out what to do. By now Markus and Carsten had seen what was happening. I heard Carsten cry, “There’s a leopard seal poking through the ice!” They raced over on their snowmobile, and Carsten jumped off and ran toward me. He had gone just a few feet when he broke through, dropping into water nearly to his waist. I caught a glimpse of Markus doing something with the Nansen sled attached to the snowmobile, but my attention was on my immediate envi-

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ronment. The seal could still lunge out and grab me from behind if I wasn’t vigilant. I was so focused on watching for the seal that I was shocked when Markus showed up, pushing the sled in front of him. I said, “What are you doing out here? It’s bad enough that I’m out here. We don’t need two of us in trouble!” But I saw the wisdom of it. I jumped on the sled, using it as a bridge over the crack. The seal came up to look a couple more times in the course of this activity but seemed only curious at this point. Markus and I pushed the sled back to firmer ice. I was pretty shaken up. For the rest of that day, I couldn’t stop thinking about it. That night I had a series of vivid dreams, and in the most vivid one the seal’s head came up and towered over me, then it transformed into a death’s head. Not a human skull, but a skeletal head of the leopard seal, with all the teeth showing. It was really spooky. The same dream repeated for several nights. Our final day at camp was the usual rush. When the US Coast Guard icebreaker Polar Star called, it was just after Markus and I had returned from our last hike to the top of the cape for final views and photos of sea-ice conditions in the colony. The “Coasties” gave us just fifteen minutes before the helicopters would arrive. We had not seen them while we were up on the cape because the captain decided to do the pick-up from 30 kilometers offshore. He was taking no chances about approaching Cape Washington’s uncharted waters. The operation began at about 5 p.m. with the first pick-up of camp supplies. Markus and Carsten went along to coordinate handling and storing our gear on board the ship. The whole process was like packing a car for a trip, but with a thirty-minute walk from the house to the car. It made for a long night, especially since the helicopters had to refuel frequently. In addition, Coast Guard helicopters cannot carry much inside, so most of our gear had to be sling loaded. This requires wrapping up the cargo in a large net (the “sling”), with ropes at four corners that converge in a hook. As the roaring helicopter hovers a few inches over the load, someone on the ground must duck underneath and attach the hook to a ring on the underside of the aircraft, hoping all the time that the engine doesn’t suddenly lose power. It’s a little nerve-wracking. The first sling-loaded snowmobile left at midnight. By the time they picked up Scott and the second snowmobile at 3 a.m., there was a bit of wind, and the snowmobile swayed and swung around a lot under the aircraft. Scott told me it was a pretty thrilling ride. I finished clearing the camp shortly after 5 a.m., under a gray and cold sky, and left Cape Washington with little ceremony. I arrived on board the

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ship at 6 a.m., where a very tired flight-deck crew greeted me. It had been thirteen hours since the operation began. By then my team had showered, for only the second time since we first left McMurdo Station two and a half months ago, making them almost unrecognizable to me. At least they were suitable for having meals with the ship’s crew and officers! As in 1986, we had a couple of days of smooth and comfortable sailing through loose pack ice to McMurdo Station. And again as in 1986, I felt conflicting emotions about leaving the cape and going home. In my debrief with the NSF station representative I was told that using helicopters in combination with a LC-130 was not practical, and the NSF wouldn’t support it in future seasons. However, there was another solution: for future deployments, we would use the Twin Otter. In between transporting us to and from Cape Washington, it would support other science projects. It was perfect! Almost too perfect, in fact. So many scientists wanted to use it, it was hard for me to get on the schedule. With this exciting prospect for the future in mind, we packed up and left on January 8, 1990. At least, we thought we were leaving. Soon after the LC-130 lifted off, there was a violent shudder. I glanced out the small window next to me and saw that the number two engine’s propeller had stopped turning. It was back to McMurdo Station for the night. The season was really over the next day, when we made it to Christchurch after a thankfully uneventful flight. We said our goodbyes on the 10th, when Markus headed to Germany to visit relatives, Scott went back to Georgia to finish his thesis, Carsten went back to school in Utah, and I left for a short visit to Australia before going back to California. After returning to my laboratory at SIO in La Jolla, I reviewed the data we had collected. The season had been enormously successful, and it was only the beginning.

... My studies at Cape Washington in 1986 and 1989 led to many questions that I knew would take years to answer. Fortunately, over the next two decades I was able to conduct eight field seasons of research, primarily at Cape Washington. My team and I were also able to visit and study the other six colonies in the Ross Sea. This was important, because to better understand the foraging patterns of the birds, we needed to know not only the variability in one colony from season to season, but also the variability between colonies. One reason for this fortunate situation was the routine addition of Twin Otters to the Antarctic Program’s fleet. All put-ins at Cape Washington after 1989 were by this aircraft, which could land on the Terra Nova Bay sea

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ice without a previously prepared airstrip. This efficient means of transport shortened our set-up time considerably. We could unload the plane in a few minutes and set up our camp a short distance away in one day. The versatility of this aircraft, mainly its ability to land almost anywhere, was also what allowed us to visit three of the seven other Ross Sea colonies. There were other changes as well. We stopped using the rugged but heavy Scott tents and used single-occupant mountaineering tents instead. The privacy was nice, in addition to being essential for our mental wellbeing. The drawback was that in large storms the tents tended to get buried by blowing snow and had to be dug out. We generally deployed and recovered our instruments at or near the ice edge. We assumed that any bird departing the colony was a breeder. If an instrument failed to return, we assumed one of three things was responsible: (1) the tag and radio transmitter had fallen off; (2) the transmitter had failed and the bird was in the colony but we didn’t know it; or (3) the bird was a nonbreeder and had no obligation to return. Mid-November was the latest we could deploy the instruments and expect to recover them before the chicks fledged and the adults left to molt. The biggest and most important change was that the field of biologging (using small attachable devices to free-ranging animals) was advancing rapidly. Several companies began making increasingly sophisticated TDRs. The size remained the same, but over time they had better batteries and more memory, which allowed me to record variables besides time and depth for the entire foraging trip the adults made when nurturing their chicks. Later, satellite trackers showed me where the penguins were foraging for this food, which was crucial for understanding the dive records I was seeing. Using these devices and other instruments, I was able to formulate a more detailed picture of emperor penguin natural history. The consistencies we found at Cape Washington from year to year, as well as at the two other large colonies of Coulman Island and Cape Roget, give me confidence that the diving and foraging behaviors I describe in the following chapters can be generalized for the species, at least in the Ross Sea. Rather than discuss this work year by year, I’ve decided it’s more useful to combine the research and discoveries of those decades. This allows me to describe individually and in depth the four critical journeys I mentioned in the preface. I will also discuss the remarkable physiology that allows the penguins to dive as they do, the interactions between the birds and their primary predator, and the status of conservation in an uncertain future.

[ Ch a pter 6 ]

The Commuter Journey

Life is not measured by the number of breaths you take, but the number of moments that take your breath away. V i c ki C oro n a

There is no particular order to these journeys, but I start with this one because it was the first of the four that we studied. When we arrived at Cape Washington in late October, the chicks had hatched several weeks earlier and the adults were in the middle of feeding them. Thus, the commuter journeys were well underway. When they hatch, emperor penguin chicks typically weigh about 350 grams. Getting a precise weight is impossible because at only one or two colonies is it physically possible to get the measurement, and it is in the depth of winter, dark, and cold, and the birds are nervous. When the young birds fledge five months later, they weigh about 12 kilograms. This represents an enormous energy transfer from the parents to the chick. During the week after hatching, the male is able to feed the chick a regurgitated “crop milk” that comes from cells lining the esophagus and has the consistency of cheese. Soon after the female returns from the twomonth sojourn she embarked on after laying the egg, the male departs to sea. He has lost 30% to 50% of his mass, compared to a loss of 20% to 25% by the female during her much shorter fast. This unequal mass loss results in little weight difference between the pair through the rest of the time raising the chick. The parents take turns commuting to sea to forage then returning with about three kilograms of partially digested fish to feed the chick. At first, the hatchling can take only a little at a time, but as the chick grows it can accept more and more, until it can take the entire amount in one shot. Each adult of a pair makes about seven commuter trips during a season, lasting from three weeks at the beginning of nurturing to less than a week at the end.

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The foraging behavior of the adults is critical to successful chick raising and the survival of the species. Since it is difficult, and in most cases impossible, to directly observe penguins feeding, most of the information we have comes from instruments attached to the animals. However, there have been a few exceptions. My first direct observation of foraging penguins was in the early 1960s, on a group of emperor penguins diving from an ice edge near Cape Royds, on Ross Island. Here I did some bird watching at its best. The penguins were diving in shallow, calm, crystal-clear water. By lying down and peering through the surface, I could see the birds searching the boulder-strewn bottom at about 20 meters. My observations were short, as they moved on fairly quickly. Just as well, because in my newness to the Antarctic I was not wise to the risk of dallying near the ice edge, since it is a favorite patrol area for leopard seals. What I was doing that day was like someone lying prone along the hunting path of a tiger. Sooner or later the tranquility may end badly. An indirect (for me) observation comes from video footage obtained by photographers on the German icebreaker Polarstern in the Weddell Sea. In a short clip, the birds can be seen catching krill grazing on algae at the bottom of pack-ice floes. The location of the krill was reliable for the penguins, with little movement between one dive and the next. It was like bottom feeding, except upside down and only two meters under sea ice. I also observed foraging behavior on video clips obtained with a “crittercam” attached by Greg Marshall, a National Geographic Society associate, to an emperor penguin diving from an isolated hole through fast ice in McMurdo Sound. The camera was too bulky to allow a normal dive, but the determined penguin, lagging behind fellow divers, stayed shallow and picked off fish known as bald notothens, or “borks” (Pagothenia borchgrevinki), hiding in the platelet layer under fast ice. It was impressive to see how far away the bird could spot a fish, swim directly to it, and snatch it—as well as several others if they happened to be hiding among nearby ice crystals. My final direct observation occurred while Paul Ponganis and I were scuba diving through a five-meter-diameter hole in thin ice near the McMurdo Sound ice edge. The hole, which was over water about 600 meters deep, had been created by a large flock of emperor penguins breaking through and diving below thin ice (plate 9). The conditions were ideal. It was dead calm at the ice edge and too irresistible not to make a dive. Phil Thorson, our dive tender, dropped a weighted line down to 10 meters. Since we were over such deep water, with no bottom in sight, the line served not only as a visual reference for

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Figure 6.1. Emperor penguins circling under the hole in sea ice shown in plate 9.

depth  but also as a safety aid in case one of us experienced a buoyancy problem. Paul and I donned our dry suits then slid up to the edge of the hole and into the water. Penguins were everywhere—swirling around near the surface above us (figure 6.1) or breaking away from the crowd and descending out of sight below like perfectly shaped missiles. We were mesmerized by their behavior, as they seemed to descend independently of each other and disappear out of sight at about 30 meters, the deepest we could see. We never saw them catch a fish, but we surmised the objective of their dives was to feed because of the routine way they came and went from the breathing hole, almost oblivious of us. Sometimes they would remain in the water to recover; at other times, they would slide up onto the ice surface and rest for a short time before returning to the water. Those rising to the hole had a 10-meter-long stream of bubbles trailing from their feathers and beak. The water was so clear that the light

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effects took on a surrealistic beauty, and the bubbles flashed like a string of diamonds. Such a scene! Who could ask for anything more? We wanted to hang out and watch much longer than our air supply would allow. In the end, we were exuberant beyond measure, and we were full of ideas about what was going on, both physically and behaviorally. This was one of the greatest dives of my life. About a week later we returned to the edge, determined to dive again. We were much better prepared this time, with twin packs of air tanks and all sorts of cameras. The penguin hole was much bigger, but unfortunately it was now functioning as a whale breathing hole, with numerous killer whales poking out of it to look around (plate 10). At the time, we did not know there were three types of killer whales in Antarctic waters: seal and penguin eaters, whale (mostly minke) eaters, and fish eaters, the latter being the most abundant. In later years, some people scuba dived with the fish-eating killer whales in McMurdo Sound, but on that day we had to assume the ones we saw were mammal eaters if they had the chance. We did not intend to be their lunch and sadly canceled the dive. 1 It was obvious from these observations that emperor penguins are opportunistic feeders, taking whatever is available. However, we also know from stomach-content studies that the majority of the Ross Sea emperor’s diet is Antarctic silverfish (Pleuragramma antarcticum), the most abundant fish in the Ross Sea. It lives in deep midwater schools and can also be found near or on the bottom. The question for me was: Where were the emperors going in order to exploit this resource? The continental shelf in the Ross Sea is composed of a series of troughs and banks. The Drygalski Basin (named after Erich von Drygalski, the Prussian polar explorer who led the first German exploration to Antarctica in 1901) borders Terra Nova Bay and has a maximum depth of 1,000 meters. The basin is unusually deep for the rest of the shelf, which is a broad plane with a maximum depth of about 600 meters. Scattered across the shelf from Cape Roget to Cape Colbeck are seven 400-meter banks, which are covered either by pack ice or open water. They are easily accessible for birds from the western Ross Sea colonies. One of these banks is Crary Bank, which lies just beyond Drygalski Basin and about a hundred kilometers east of Cape Washington. (As an aside, the bank was named after Albert “Bert” Crary, a geophysicist and glaciologist, the first person to stand at both the North and South Poles, first chief scientist of the US Antarctic Program, and the only person to survive a tumble off a 20-meter-high section of the Ross Ice Shelf. In fact, he is per-

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haps the only person to fall off the shelf. In 1961, he gave an entertaining introductory talk to new recruits like me describing how he survived the fall. The kernel of wisdom from his story is never walk close to the edge of an ice cliff, which is often made up of a thin snow cornice.) Based on tracks we obtained from satellite transmitters attached to several birds, the residents of Cape Washington bypass the deep waters of the Ross Sea continental shelf, and Crary Bank is a favored destination. We hit the jackpot in 2011 when, as a favor to me, Paul Ponganis attached an advanced TDR with satellite tracker to a commuting adult. After leaving the colony, the bird swam across the Drygalski Basin and by the third day was at Crary Bank. It continued easterly over the bank, diving all the while, until the sixth day, when it turned back toward Cape Washington. It left the bank on the eleventh day and a day later arrived back at the colony. Dives of greater than 400 meters occurred only while the bird was over Crary Bank (figure 6.2). This result influenced my interpretation of past dive records and compelled me to review them in light of where the birds might be going to hunt. Figure 6.3 is a typical record of a deep-dive bout. There are two preliminary dives, probably for midwater assessment for prey. Then there are eight deep dives to about 470 meters. The surface interval between each deep dive in this record was between twelve and twenty minutes. Often there were shallow dives during this time, and I assumed they were for recovery,

Figure 6.2. The twelve-day track and diving profile of a commuting emperor obtained in November 2011. (Plot generated by K. Goetz.)

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Figure 6.3. A three-and-a-half-hour dive record of Cape Washington penguin no. CW4–95.

not hunting. Where the surface line is flat and solid, it indicates that the bird was out of the water and on an ice floe, based on input from a wet/ dry sensor. Each deep dive had a steady rate of descent and ascent, and the depth of each dive was within just a few meters of other dives within the bout. The idea that these repetitive dives are for feeding is logical. The consistent depth, with no or only small changes in depth at the bottom of the dive, strongly suggests hunting at the top of a bank. Even though most penguin foraging dives (including those of emperors) are in the epipelagic zone (down to about 200 meters), records like the one above led me to believe the Cape Washington birds were also deep demersal (near bottom) or benthic (on the bottom) hunters. About twenty years ago, a French biologist noted that penguins from the Pointe Géologie colony, near France’s Dumont d’Urville station in East Antarctica, were benthic foraging on 200-to-300-meter banks and ridges along the continental shelf. However, the shelf is narrow along the East Antarctic coast, so from time to time those banks and ridges are covered with fast ice and inaccessible. This forces the birds to forage in water so deep that they have to hunt pelagically for a less reliably located prey. They also have to walk or toboggan farther over fast ice to access water to dive in. The situation may be a contributing factor to high chick mortality at that colony in some years. My friend and fellow penguin biologist Barbara Wienecke, along with her collaborators, also found that most of the birds from the Auster colony in East Antarctica, near Australia’s Mawson Station, hunted in shallow water about 200 meters deep. Out of ninety-three birds and 137,364

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recorded dives, only one of her birds dived deeper than 500 meters. It did it in spectacular fashion, though, diving to a record 564 meters! The bird must have been in deep oceanic waters beyond the narrow shelf in the area and wondering where the bottom was. So while it is apparently not unusual for emperors to feed near or on the bottom, the remarkable thing about western Ross Sea birds, and Cape Washington birds in particular, is that they do it so deeply and so often. I analyzed my dive records from all eight seasons between 1989 and 2011 and found that thirty-five of the forty-two birds in my studies dived to a depth greater than 400 meters during their trips, and eight birds routinely dived deeper than 500 meters (table 6.1). The deepest dive was to 552 meters. Out of the total 83,943 dives for all birds during those seasons, the total number of deep dives was 1,293, or about 1.54% of all dives (though they probably represented 10% of all foraging dives). That does not seem like much, but how important were they? I compared the number of deep-hunting and shallow-hunting dives within the same time frame, and the results were provocative in regard to the relative importance of each. Using one bird as a typical example, the time spent at depth for each of its dives, both shallow and deep, was approximately two minutes. However, the transit time to and from depth was much longer in the deep dives, resulting in dives that were more than twice as long as the shallow ones. The deep dives also had long pauses between them, whereas shallow dives had only brief stops at the surface. Therefore, there was a large time investment for the bird’s deep dives relative to its dives to less than 50 meters. The deep dives occurred at about one to two dives per hour, while the shallower dives were made at a rate of about fifteen per hour (figure 6.4). For one hour of diving at midwater depths, the total time at depth was thirty minutes, versus four minutes at depth during an hour of deep diving. My conclusion was that it took less time to satiate during the deep dives. In other words, the bird must have caught more fish by weight during each deep dive than during shallow dives. Why would this be the case? When emperor penguins are feeding in midwater, the short recovery is important in allowing the bird to get back to the fish school quickly, as the school might break up, move on and be harder to find, or get depleted by many predators feeding on it simultaneously. In contrast, if the prey are on or near the bottom, it’s more likely they would not move far between dives, and the sea floor would have many reference points to help in locating them. Also, the extreme depth would preclude other, competing predators, such as Adélie penguins. Prey may also be more abundant near the bottom than in the midwater

Table 6.1. Summary of birds that exceeded 400 meters during a commuter trip Year

Bird No.

Body Mass Trip DuraMaximum TotalDeep (Kilograms) tion (Days) Depth (Meters) Dives

Total Dives

% Total

1989 CW11–89

28.0

11

531

55

3,315

1.66

CW12–89

25.0

12

464

68

3,322

2.05

1990 CW2–90

27.0

8

471

44

2,255

1.95

CW3–90

22.7

15

471

59

4,313

1.37

CW9–90

27.7

18

482+

143

2,255

6.34

CW10–90

21.5

9.5

438

16

2,103

0.76

CW11–90

22.0

11

531

54

2,625

2.06

CW13–90

27.1

17.4

483

11

2,728

0.40

CW14–90

24.9

8.7

528

34

2,470

1.38

CW23–90

30.3

8.3

436

51

1,179

4.33

CW31–90

29.2

7.9

464

57

1,464

3.89

22.5

7

486

99

2,621

3.78

CW10–92

24.2

23.3

492

136

4,276

3.18

CW11–92

22.0

16.3

441

30

3,141

0.96

CW13–92

25.4

17.4

468

19

1,964

0.97

CW15–92

26.0

9.3

450

21

3,043

0.69

CW16–92

23.8

9.3

444

7

1,706

0.41

CW18–92

24.3

405

21

1,706

1.23

CW21–92

27.9

8.2

462

4

2,134

0.19

CW22–92

22.9

14.3

484

25

2,151

1.16

CW4–95

24.2

14.1

552

93

2,771

3.36

1996 CW3–96

26.5

13

460

17

2,683

0.63

CW8–96

28.4

7

480

24

1,125

2.13

CW1–11

25.5

11

470

136

1,292 10.05

1992 CW2–92

1995

2011

10

Totals

1,224

58,642

2.09

Note: No birds from 2005 were included in the table, which explains the difference in total dives (58,642) and percent deep dives (2.09%) here from those quoted in the text (83,943 and 1.54%, respectively). The records for 2005 were incomplete due to delayed starts of up to ninety-six hours after release. Also, the TDRs were of a different make, with a much faster sampling rate, so the deep-dive data were not comparable. In summary, four of the nine records from that year had dives that exceeded 500 meters, three of those by just a few meters. The other five records all had depths exceeding 400 meters.

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Figure 6.4. A shallow-dive bout by penguin CW8–96. The two 300-plus-meter dives are probably for searching. The dives before the second deep dive are probably travel dives, and those following the second deep dive are foraging dives. (The birds got lucky this year [1996], as abundant prey seemed to be shallower and closer to the colony, resulting in shorter foraging trips and earlier fledging of the chicks.)

column, and they may also be easier to catch, as the benthos sets a limit on at least one direction that they can go to escape hungry predators. In some ways, it would be like those penguins feeding off the bottom of the sea ice, only in reverse. Like the krill, the demersal (near the bottom) or benthic (on the bottom) silverfish would have a specific and limited location. They may be relatively easy to catch for another reason. Fish tend not to move quickly in frigid Antarctic waters, making them nearly defenseless against warm-blooded predators. This has been demonstrated by divers near McMurdo Station, who have literally caught bottom-dwelling fish by hand. All the emperors have to do is find the silverfish. Once they do, there is probably little effort involved in capturing them. If the fish are larger, as Antarctic silverfish are known to be near the bottom, it is yet another advantage, in that each catch is more rewarding than a single catch farther up the water column. To differentiate a little more between shallow and deep dives, we concluded that the very shallowest dives, especially the ones at the beginning and end of a trip, are for travel. Therefore, the total number of dives in a trip varied greatly, depending on how far a bird was traveling to a favored dive site. The most dives made by a deep diver were 4,313 during a fifteen-day trip, and the least were 1,141 during a four-day trip. In regard to energy expenditure, traveling dives may be the most costly,

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as the birds move rapidly and induce much drag swimming near the surface—especially when breaking through the surface, as they often do (plate 11). In fact, breaking the surface causes high induced drag, which is why most penguins leap clear of the water to reduce drag while they snatch a breath. This is called “porpoising,” and it is a characteristic swim pattern of porpoises, dolphins, sea lions, and fur seals. If it had been seen first in penguins it might have been called “penguinning.” It is interesting that emperor penguins, as far as I know, are the only penguins that do not porpoise. Why? I don’t know. Deep dives, in contrast, may be the most effortless, as they probably include periods of gliding. During descent, the positively buoyant emperor penguin at first takes deep strokes, but its effort declines as the air in its air sacs and trapped in its feathers compresses to a small enough volume that the bird becomes negatively buoyant, allowing it to coast downward. Near the bottom of the dive, stroking increases as the bird begins to search for and pursue prey. During ascent, it strokes toward the surface then once again can glide as its body buoyancy becomes positive (see chapter 10). Since we often observe free-swimming emperors in groups (figure 6.5), it may be that they also swim as a flock when traveling and when diving to hunt. This could have two advantages. First, groups of rapidly moving, identical individuals can confuse predators, making it difficult to single out

Figure 6.5. A team of emperors under thick ice.

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one individual and therefore reducing any single individual’s risk of being taken. It’s the same reason that some fish have evolved to travel in large schools. Second, hunting in groups may help in locating prey, as several penguins moving through the darkness at depth would flush the fish, causing bioluminescent organisms around them to light up as they scatter and making them easier to see. Deep diving is a dangerous endeavor, however, for what must be a special meal. There is physiological stress for a penguin to dive so long and deep. The risks for hunting large silverfish near the bottom also include a potential attack by a large predator, such as an enormous deepwater octopus (species uncertain) or a colossal squid (Mesonychoteuthis hamiltoni). Both are larger than emperor penguins, and little is known about their natural history: how often they feed, their preferred prey, and their preferred depth. For these large predators, a flock of emperor penguins diving deep at the bank might seem a windfall from the upper reaches. Do emperor penguins face the challenge alone or as a group? Either way, encounter-

Enormous Octopus The largest known Antarctic octopus is the so-called giant Antarctic octopus (Megaleledone setebos), which reaches 90 centimeters in total length and preys on shelled mollusks. However, in 1993, a fish biologist pulling up a trap from about 500 meters deep in McMurdo Sound was surprised to find a massive hitchhiker sitting atop the trap. It was an octopus at least twice the size of M. setebos, and its weight was estimated to be between 45 and 50 kilograms. The creature was placed in the McMurdo Station aquarium, where it remained for a little over a week. Since no one could locate a container large enough to preserve it and send it to the Smithsonian Institution for identification, it was ultimately released back into the sound. The only records of its existence are photographs and videos taken while the animal languished in a large aquarium tank. The tank was three meters in diameter, and when the octopus stretched out its tentacles, they nearly reached from one side of the tank to the other. Little is known about life in Antarctica’s ocean, and the possibility that there are as-yet undiscovered species lurking in its depths is very real. Was this octopus simply a very large M. setebos, or was it an entirely new species? We suspect the latter, but without a physical specimen, there is no way to know for certain. Based on its size, however, it is reasonable to assume the animal was large enough to prey on small-to-medium sized Antarctic toothfish (Dissostichus mawsoni) (which are commonly found at a depth of 500 meters and weigh between 30 and 80 kilograms) and therefore large enough to take an emperor penguin, should one cross its path.

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ing either one of these predators—and especially a giant squid—could be dangerous for the birds. The effort and risk in diving deep are such that the birds would not be doing it so routinely if they weren’t successful. My conclusion is that for experienced birds deep dives are the foundation of successful foraging, at least from Cape Washington. Since that colony is one of the largest, it is meaningful to ask: What are the secrets of its success? Deep diving is one of those secrets, and it is especially apparent to me when considering those birds with high deep-dive counts (such as CW1–11, CW2–92, CW10–92, CW9–90, and CW4–95) (table 6.1). These emperor penguins were mainly demersal or benthic foragers whenever they were in a region with a rich bottom they were capable of reaching. At least one of these desirable banks is within in reach of commuting emperor penguins from all the Ross Sea colonies. The banks may also be crucial for some of their other journeys, as described in the following chapters.

[ Ch a pter 7 ]

The Fledging Journey

Where is everybody? Enr ico Fer mi

In mid-December, the chicks are converting to juveniles (i.e., they are fledging), which we define as their first entry into water. At first they are hesitant, walking along the ice edge, peering over the edge, and calling back and forth. Sooner or later one will flop into the water, and the rest usually follow. Their introduction to the aquatic life is not always so gentle, however. In 1993, my son Carsten and I witnessed a once-in-a-lifetime event. Drifting snow had formed a gently sloping ramp from the sea ice onto a grounded iceberg, and a flock of departing chicks had marched up the ramp onto the berg. They were stopped by a 20-meter cliff over a sea that was sometimes open water and other times crowded with ice floes. In true juvenile behavior, they did not turn back and go down the slope and instead just waited at the top of the iceberg. Since these birds tend to just follow the crowd, over the course of a couple of days almost two thousand chicks gathered at the top of the iceberg. Finally, they started walking off the cliff (plate 12). Not jumping or leaping, just stepping out and falling head over heels, sometimes doing two flips before hitting the water with a resounding plop. No Olympic medal for this performance. Their cushion of feathers and down apparently protected them from any damage, and they quickly rose to the surface and swam away, calling the whole time. At times there were at least eight birds tumbling through the air at once. To their credit, they never walked off the edge when the landing area was cluttered with ice floes. Not to be outdone, a few Adélie penguin adults followed the emperor penguin juveniles onto the iceberg, over the precipice, and into the water. In their case, however, they executed a perfect “swan dive” as they rocketed down the steep slope into the water. Clearly, they had done this before.

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Finally, some of the juveniles decided discretion was the better part of valor and walked back down the slope. Once a few of them started, the rest fell into step and marched back to the flat sea ice from where they had come days earlier. Then they all stepped into the water from there. The bad part of all this was that the time lost meant valuable body fat was burned before they were able to go to sea and begin feeding. However the chicks entered the water, it was a conversion by immersion. They swam away and didn’t turn back. And then they just seemed to disappear. During my first two seasons at Cape Washington, in 1986 and 1989, I was puzzled by the absence of fledglings after they left the colony. Coarse calculations suggested that there were about sixty-four thousand juveniles piling out of the six western Ross Sea colonies (seventy thousand if you count Cape Colbeck, which I didn’t know about at the time), but once they left we never saw them again. Not in the vicinity of the cape, and not near  any  of the colonies we might fly or sail by on our way home at the end of February. That was also true for my colleagues at McMurdo Station as well as for friends who were guides on tour ships passing through the Ross Sea. This led to one basic question, as embodied in the quote above. In Fermi’s case, the question was in response to a discussion regarding the statistical probability of other civilizations existing in the galaxy. In my case, you might call it the 64,000-emperor-penguin-juvenile question. By the early 1990s, satellite transmitters small enough to put on fledgling emperor penguins became available, and we took immediate advantage. We searched groups of chicks congregating at the ice edge that were clearly ready to go to sea, and we selected the largest ones we could find. Their average weight was 13.4 kilograms. We attached the satellite transmitters (we used the term tags for either the transmitters or the various TDRs we were using) on top of the feathers with a special epoxy. The logic was that, in time, the glue would decay and the tag would fall away, most likely after the transmitter battery was exhausted of power. We did not want the juveniles burdened with an inoperative transmitter until they molted months later. At this time, all the chicks were either marching toward the ice edge in groups, or they were clustered at the edge itself. Some of these latter groups stretched from the ice edge to a couple hundred meters back. Others were well back in Terra Nova Bay, four to five kilometers from the edge but headed in that direction. It was like they were all going to a party, with everyone calling back and forth as if saying, “Time to go! Time’s a-wasting, and so is your body mass!”

Plate 1. Emperor penguins on the sea ice.

Plate 2. Conflict between a young male Antarctic fur seal and king penguins on the beach at South Georgia Island. Both were considered endangered because of human exploitation but have since made exceptional returns to pre-harvest population levels.

Plate 3. Cape Roget at sunrise, looking northwest toward the Admiralty Range.

Plate 4. Cape Washington colony, showing the cape at left and grounded icebergs at the ice edge.

Plate 5. The LC-130 on Priestley Glacier, with the tail ramp down to unload our gear.

Plate 6. Penguin City: The Cape Washington colony, with Mount Melbourne in the background.

Plate 7. The Possession Bay colony is along a river channel just below the base on the ridge to the left. The buildings in the square are the base’s fuel storage tanks, garage, and workshop.

Plate 8. Chicks huddling at −18°C (−0.4°F).

Plate 9. A large flock of birds had created a hole in a new thin-ice field attached to the thicker fast ice of McMurdo Sound. The thickened edge was caused by the activity of the birds; as they came out of the sea, water dripped from them and froze at the edge of the hole.

Plate 10. The same hole, now occupied by killer whales.

Plate 11. Emperors porpoising. In this group, the five birds are in different levels of leaving and entering the water. Note that none are completely clear of the water, or even close to being airborne.

Plate 12. The penguin plunge. The lip of the iceberg is about 20 meters high. In this photo, there are five birds in the air. Not an organized flight wing!

Plate 13. With loud calls, the chicks swim toward the horizon, which is cluttered with pack ice.

Plate 14. The chicks crowding behind the adults will get their first and only lesson in the departure to sea when the adults make their intense rush to the water.

Plate 15. A molting emperor penguin. Juveniles occasionally begin the molt early, while still in the colony.

Plate 16. An emperor penguin partially buried in snow during a blizzard.

Plates 17a and 17b. An illustration of pupil enlargement in a king penguin.

Plate 18. A leucistic emperor penguin. With no countershading, this all-white bird will be prominent among its companions in the blackness of the depths and a target for a visually hunting predator, such as a leopard seal.

Plate 19. A landing bog next to a high-use exit hole, a formation that we called a “death pit.” Note the thin ice edge near the top of the photo and the preferred hole the birds are leaping from at the edge of the thick fast ice.

Plate 20. A group of fifty to a hundred adults making a rapid toboggan across a narrow ledge of thin ice, after an extended pause at the ice edge. Their haste shows a desire to move quickly past the danger zone, where a leopard seal may be lurking under the thicker ice. One of the seal’s several tactics is to ambush prey in this area.

Plate 21. Flying emperor penguins leaping from the sea onto ice.

Plate 22. A midair catch by a leopard seal of a returning emperor penguin. The bird arriving on the left is at about the same height above the ice as the one caught by the seal. (Photo by T. Kooyman.)

Plate 23. Viewing a leopard seal from a cage allowed us to learn much about this animal and its boldness, without concern for its proximity or generally aggressive behavior.

Plate 24. A group of emperors ascending toward the exit hole, streaming contrails as they go.

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For us, we were reminded of Yogi Berra’s famous quote: “Be careful. If you don’t know where you’re going, you might wind up someplace else.” They don’t have a choice, of course. At this time of year (December and January), intense solar radiation is heating the ice, causing it to deteriorate. If the chicks don’t jump in voluntarily, the disintegrating ice will dump them in. When each group reached the edge they joined other groups, and often these combined groups would grow to several hundred chicks. Such large groups made for spectacular departures. They would mill about for a few hours, as though hesitant—which is not surprising, since they had never seen water before. Then, when they finally tumbled in, the entry was not graceful. It was as though when they stepped off the ice they expected to keep on walking. It didn’t work out that way. After spending the previous five months growing and developing on firm ice, that step into nearfreezing water must have been shocking. 2 Once in the water, they always headed south. The larger the group, the longer the line of fluff y balls, as most were still 60% covered in gray down over their adult plumage. There was much wing flailing at the surface, but not much propulsion as they “swam” along the surface. Between the wings slapping the water and the chicks “screaming” loudly all the way to the horizon, it was a noisy activity (plate 13). 3 And that was the last we saw of them. We learned from the tags that they did not continue south after passing out of our sight. They turned north and kept on going for days and weeks until they finally left the Ross Sea and moved into the Southern Ocean, going as far north as 54° S. The birds were on their way, minitorpedoes plying the southern seas! What an unexpected result for me! Over three years of hanging out each year at a crumbling ice edge, jumping over crack after crack, and dancing from floe to floe to attach tags, we followed the track of ten birds. These ten birds were probably a good sample, because their tracks were consistent over the three years, and later studies from East Antarctica had the same result. The total time we followed them ranged from fifteen to eighty-one days, with an average of sixty-four days (figure 7.1). It was surprising that they not only left the Ross Sea but plunged deep into the Southern Ocean, traveling as far as 2,845 kilometers from the colony. At 56.9° S they were closer to New Zealand than to their natal colony. Even so, they were in the most remote sector of the world’s oceans, a long way from land from any direction, and therefore not likely to be seen by any human. Their northern journey was not direct, and it ended in April, which is

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Figure 7.1. The tracks of six different juveniles carrying satellite transmitters over the austral summers of 1994–95 and 1995–96. The end location is the point where the signals ceased. (Modified from G. L. Kooyman, T. G. Kooyman, et al., “Penguin Dispersal after Fledging.”)

long after the scientists and tourist ships had left the Ross Sea. By then, the juveniles had returned south to the pack ice and were scattered across the Ross Sea, probably in small groups or even alone. No wonder no one ever saw them! Transmissions from the tags lasted long enough that I became skeptical of the common assumption that there was high chick mortality after their initial step into the sea. Only the short, fifteen-day record was most likely caused by predation. The loss of transmission from the other tags was probably because the battery died, or else the tag sloughed off the bird’s back. When I published a note in Nature on these results, it caused a bit of a stir—and some consternation, because the northernmost part of their route was outside the Antarctic Treaty boundaries, meaning the birds were completely unprotected from being incidentally caught if there was commercial fishing in the area. If they stayed with the West Wind Drift, also known as the Antarctic

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Circumpolar Current, they might bump into South America. In fact, some do. Before 1971, there had been eighteen sightings of juvenile emperors north of the Antarctic Polar Front, six of them at Tierra del Fuego, at the southern tip of South America. One was also spotted there in 1975 and another in 1992. I saw one at South Georgia Island in 1976, while on an expedition aboard the R/V Hero, an NSF research vessel (now decommissioned) that was half sailboat, half motorboat. Among those aboard were two well-known ornithologists, Frank Todd of SeaWorld San Diego and Maurice Rumboll of the Natural History Museum of Buenos Aires. The three of us hung out in the whale-watch tower, looking for wildlife. I loved sailing on that old wooden ship, but this enjoyment was not shared by the other members of our expedition. From the time we left Ushuaia, Argentina, until we neared South Georgia Island, I never saw any of them, perhaps because the Hero was notorious for generating seasickness. Maybe another reason the rest of the guys did not show was that both Frank and Maurice were heavy smokers, and wherever they were the room was always thick with smoke. It was no problem for me; I grew up in a smoke-filled house. In 1985, British Antarctic Survey staff saw a second emperor penguin juvenile on South Georgia—at Saint Andrews Bay, of all places. They were doing a survey of the king penguin colony and spotted the bird just after Phil Thorson and I had left. Now that would have been a surprise, if we had seen that emperor penguin! To be sure I had the correct information about the juveniles’ travels, and to answer some questions about their physiology, my team and I did another experiment in early 2001. We knew from earlier experiments that the chicks at the time of fledging did not have a fully developed breathhold capacity. The question was: How long did it take to develop high concentrations of hemoglobin in their blood and myoglobin in their muscle? (These are oxygen-carrying molecules. Marine mammals and diving birds in particular have high levels of myoglobin in their muscles, which allows them to extend their dive times. See chapter 10.) At the normal fledging time of mid-December, a chick’s myoglobin concentration is only half that of an adult. We captured six chicks just before they fledged and corralled them on thick fast ice at the most southerly part of McMurdo Sound, keeping them there for several weeks. I remained with them for a short time, and afterward left them in the capable hands of Markus Horning and Lisa Starke. Lisa was an outstanding undergraduate student at the University of California San Diego before she came to work for me and Paul at SIO, where

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she assisted us with many experiments on penguins, seals, and sea lions. Shortly before I left Antarctica, she had rescued one of our soon-to-be juveniles. While it was swimming below our isolated dive hole, a Weddell seal had clamped it in its jaws. When the seal came to the surface with the bird firmly gripped between its teeth, Lisa, without hesitation, bent way over the hole, grabbed the bird, and pushed the 400-kilogram seal away. After that incident, we named the bird Lucky. Over the next month of raising and observing the chicks, Lisa and Markus watched them pass to the juvenile stage, learning to swim and nearly doubling their body mass on fresh-caught fish. By January 25, the birds were ready for release at the McMurdo Sound ice edge, which at that time was about 30 kilometers north of the corral, at a latitude of 77° S and about 400 kilometers south of their original home at Cape Washington. They were fully feathered by then, with no down. Using the same type of transmitter as before, we tracked them as far as 1,750 kilometers from their ice-edge departure point. One tag stopped transmitting at 6 days, while the longest one went for 176 days. They traveled north and followed the same basic track as the birds in the previous study, except they did not go any farther north than 63° S. The smaller latitudinal change from the earlier study was likely because they started their journey four weeks later than they normally would have, and at four degrees of latitude farther south. When we released them, they were sleek, beautiful miniatures of the adults. From the last transmissions we received, we learned they were diving to 160 meters, which made them bona fide divers that measured up to the abilities of king penguins. Their migration to the far north and out of the Ross Sea shows how ingrained the motivation was for doing that. All these experiments had answered my three basic questions: Q: What happens to the chicks after they fledge? A: They initially head to the far north. Q: Are the fledglings successful against all odds, without swimming skills or knowledge of predators, and with no one to teach them what to eat and how to catch it? A: Apparently so. In our sample of sixteen birds, only two died during the critical time of getting their sea wings and diving deep to feed. Q: In their haste to get going, did they get where they wanted to go? A: Also apparently so. Studies by other researchers at northern colonies outside the Ross Sea confirmed what we had discovered, including when the juveniles turned south and headed back to the pack ice. Two of these studies were conducted by Barbara Wienecke, the first in 1996 at the Taylor Glacier colony, where she deployed seven transmitters,

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and the second in 2007 at the Auster colony, where ten birds were tagged. Both colonies are on the East Antarctic coast, near Australia’s Mawson Station. There were two big differences between her studies and mine. First, her two colonies were at 67.4° S latitude, about 675 kilometers further north than Cape Washington. Second, birds from those northern colonies had to walk 50 kilometers to reach the ice edge, a “march of the penguins” that took them about eight days. Because of that, Wienecke never saw the actual entry of the birds into the water nor had the thrill of that experience. When she released her birds, they weighed about 15.5 kilograms. Although initially heavier than the Cape Washington birds, they probably lost enough body mass during the exertion of their trek to the ice edge that they weighed about the same when they finally entered the water. Wienecke’s tags transmitted from 28 to 189 days. The most northern latitude the birds reached was 56.2° S, and the maximum distance from their colony was 2,343 kilometers, which was about 500 kilometers less than in my experiments. Another experiment looking at fledgling departures was conducted by a French biologist in 2013 at the Pointe Géologie colony. The fledglings in this study weighed an average of 16.3 kilograms at release, but they also had a long walk to the ice edge. They ranged north to 54.7° S latitude, and the maximum distance they traveled from the colony was 1,250 kilometers. Transmission from the tags lasted up to 255 days. These tags recorded depth also, and when in pack ice, the birds dived to between 50 and 100 meters, versus when in open water near the Antarctic Polar Front, where they dived to nearly 300 meters. The researchers speculated that the birds’ food in the ice was krill, amphipods, and silverfish, but none of these occur north of 60° S. North of that latitude, and over a bottom too deep to ever reach, the birds are probably predators of lantern fish, similar to king penguins. The most detailed study was done by another French biologist, again at Pointe Géologie in 2013. The team tagged fifteen fledglings, and their records lasted up to 344 days. Their maximum dive depth was 264 meters, in deep water, and the greatest distance from the colony was 3,503 kilometers. The lowest latitude reached was 54° S, and the juveniles turned south in March/April, returning to the pack ice by April/May. The last transmission was in mid-December 2014, near the northern ice edge. I was gratified to see that these results were remarkably similar to my studies at Cape Washington and McMurdo Sound. The fledging journey out of the Southern Ocean and to the Antarctic Circumpolar Current is clearly fixed within the species. It is a journey radically different from those of the adults. For the Ross Sea birds, their diet, especially at the farthest

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north of their travels, probably consists of lantern fish and several species of invertebrates that don’t occur in Antarctic waters, whereas adults subsist primarily on a diet of Antarctic silverfish. Also, the juveniles are at risk from a much wider variety of predators, from leopard seals and killer whales in Antarctic waters to unknown species outside those waters, including sharks, fur seals, southern sea lions, beaked whales, and pilot whales. As a final note about how dangerous the Southern Ocean might be, there is a case where a juvenile emperor penguin beached itself near Wellington, New Zealand. After two and a half months of rehabilitation by well-meaning wildlife experts, this bird was tagged with a transmitter and released at 52° S latitude, about 200 kilometers farther north than any of the other tracked juveniles reached. Transmission from the tag lasted only four days, and the bird made it only 113 kilometers to the southeast.

[ Ch a pter 8 ]

The Pre-molt Journey

Should we die before our journey’s through, Happy day! All is well! W i l l i a m C l ay to n

Sometime, around the middle of December, the Cape Washington parents have had enough of commuting back and forth from the feeding grounds, whether at Crary Bank or elsewhere. The weather is warmer and the fast ice in the colony is melting. They gather at the ice edge for one last departure (plate 14). Often there are chicks present as well. Suddenly there is a rush of adults, and a feathered waterfall of penguins goes over the lip and splashes into the sea. After a high-speed burst to 20 meters offshore, they often pause to groom. This entails a vigorous rolling back and forth flapping their wings hard at their sides. Sometimes this activity is broken up by a leopard seal intruding into the crowd, and the penguins all scatter and re-form farther from the edge. Soon they are gone, and another group of adults begins to form. The birds are on the most dangerous trip of their lives—until next year, when they do it again. The intrusion by the leopard seal is but a prelude to the risks before them. 4, Like the juveniles leaving the western Ross Sea colonies, when 5 the adults left the colony after nurturing the chick, they just seemed to disappear. I knew they were going somewhere to molt, but where they went was a mystery. It was a mystery I was determined to solve. The only way to do that was to attach satellite transmitters to the birds late in the season, when they were leaving. Normally, access to the colonies at this time is not practical. The ice is decaying rapidly, and landing aircraft on it is generally not possible. However, my sea-ice camp at Cape Washington was fortuitous in this regard. We were still there at that time of year, and we could attach transmitters to birds at the ice edge when they gathered for their final departure. We did this in 1992 and 1993.

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Polynya A polynya is an area of open water surrounded by sea ice, either pack ice or fast ice. One would normally expect to find sea ice in these locations, but it is prevented from either forming or accumulating by a variety of factors, including offshore winds and/or the upwelling of warmer water.

We also attached transmitters to birds at the Cape Roget, Coulman Island, and Cape Crozier colonies, though we had to do it a little earlier in the season, when those colonies were still accessible. We took the chance that the instruments would continue working until the birds arrived at the molt site. Fortunately, some did. In all, we released fifteen birds with transmitters from the four colonies. At the end of their journeys we finally knew where they went, and it was consistent for all of them. Though the sample size was small, I felt it was good enough to reflect what most of the colony populations did. Their approximate departure date was between December 6 and December 20. All the birds traveled for about a month across the Ross Sea polynya to the eastern Ross Sea near Cape Colbeck (figure 8.1). The direct distance of travel was 1,245 kilometers, plus or minus 153 kilometers, but they didn’t go in a straight line. They traveled 47 kilometers per day, though that didn’t include vertical travel while they were hunting—and they must hunt and feed during this journey. Their arrival date at the molt area ranged from January 22 to January 31. The satellite tags did not transmit when they were in the water, so each mark on the tracks indicates when the birds had climbed onto the ice. It’s therefore easy to see where in their journey the penguins were swimming, and sometimes covering large distances in relatively short time spans. It was satisfying to solve the mystery of the molting location, but the satellite transmitters also shed light on how dangerous the journey is for the birds—and not so much because of predators, though that is always a risk. The danger on this trip is fuel. The birds we tagged left with an average body weight of 25 kilograms. While traveling, they must find food abundant enough for them to gain 10 kilograms if they are to survive the molt. Think about it. It is like taking a light plane across the southwestern desert from San Diego, California to Tucson, Arizona with only half a tank and a need to arrive with a full tank if you are to survive. You can only succeed if you know where some fuel stops are on the way. In the case of the penguins, they must survive a thirtyfive-day fast once they arrive, because they cannot enter the water while

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Figure 8.1. The track from bird no. CW87 shows that it departed Cape Washington, traveled closely parallel to Pennell Bank, left the bank a few days before it left the continental shelf, and ended up near an unidentified island north of the Ruppert Coast. CZ70 departed Cape Crozier and crossed the Hayes and Houtz Banks, ending up very close to the same location as CW87. The X’s mark the molt locations of other birds. For example, the X nearest Cape Colbeck marks where bird CC67 terminated its journey. The center X marks the endpoint for bird no. CI21. CW = Cape Washington, CZ = Cape Crozier, CC = Cape Colbeck, CI = Coulman Island.

molting. So just like the light-plane pilot, they must know where they can find sufficient fuel during the trip. During the molting process, all their old feathers are replaced with new ones. The birds must stay dry and conserve energy by moving very little (plate 15). If they arrive at the molting site underweight, they will have a problem, because the consumption of body mass during molt is very high, about 600 grams per day. In contrast, males lose only 123 grams per day during the 120-day winter fast when they are incubating the eggs. The difference has to do with both ambient temperature and feather production. In the winter, all the birds have to do is keep themselves and their eggs warm. This is not much of a challenge considering their insulation and their cooperative behavior. Even though the winter temperature is as low as −40°C (−40°F), the birds huddle, and in the huddle it can be more than 20°C (68°F). (That’s correct, not a typo.) During the molt, the birds will be in groups, but they don’t huddle, which exposes them to colder temperatures. More important, feather pro-

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duction is very expensive energetically. At 600 grams per day, a bird that arrives with a body mass of 35 kilograms and fasts for thirty or thirty-five days will lose about 18 kilograms and weigh only 17 kilograms at the end. This is a tenuous body mass for survival. So where do they find a food supply abundant enough to fatten them over the thirty to forty days of travel time to the molting site? Based on two tracks, one from Cape Washington and the other from Cape Crozier (figure 8.1), we might speculate where these birds of the Ross Sea fed. The Cape Washington bird (no. CW87) left the colony on December 22, 1993 and arrived by a looping track at the eastern Ross Sea. The direct-line distance was 1,290 kilometers, but the bird’s actual travel along the northern loop was 1,600 kilometers. Its route went to the north, crossed over the Crary and Pennell Banks, then turned southeast and traveled over deep water, paralleling the edge of the Ross Sea continental shelf before arriving in the western Amundsen Sea on January 22, 1994. This animal likely fed on silverfish while near the banks and krill when over deep water beyond the shelf. From the southern colony of Cape Crozier, bird no. CZ70 left on December 9, 1992 and arrived in the western Amundsen Sea about January 23, 1993. Within five days of travel, this bird was 400 kilometers from its starting point and past the Scott Bank. In the next month, it likely passed over the Hayes and Houtz Banks before arriving at its destination. This bird possibly fed demersally on silverfish, followed by pelagic feeding on krill before arriving at the molt site. In both cases, the birds were near the end of their journeys when they left the narrow continental shelf and were offshore in deep water northeast of Cape Colbeck. The destination of molting birds is an area of multiyear, large ice floes of great concentration. At nearly 150,000 square kilometers, it’s equivalent to the state of Georgia. For a more Euro-Asian comparison, the molt area is about the same size as Kazakhstan, or three times the size of Denmark. Once birds arrive at the molting site, the hazards of their journey are not over. They cannot enter the water during the molt. To do so without an intact coat of feathers would mean certain death by hypothermia. So they have to find a place where there are large enough ice floes and be confident that, even in the heat of the summer, the floes will remain intact for the thirty-five days needed for the molt. I wondered how they knew the eastern Ross Sea was such a place. If they were experienced breeders, they had been there before, of course. What about first-time breeders? Perhaps they just followed the crowd they departed with. In any case, I learned later that finding an adequate floe was easy.

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Figure 8.2. Emperor penguins on a giant ice floe in the molting area. This floe, estimated to be 30 kilometers long and nearly as wide, had several groups of molting emperors scattered across it.

A few years after my study, John Bengtson, director of the Marine Mammal Laboratory at the National Oceanic and Atmospheric Administration’s Alaska Fisheries Science Center, invited me to join his January–February Antarctic Pack Ice Seals (APIS) cruise to the eastern Ross Sea. Most of the floes in the area were big; one was 30 kilometers long (figure 8.2). That is the size of Catalina Island, off the California coast. It gave me pleasure not only to see this place firsthand but also to respond to this question from a marine mammal population estimator: “Will we see many emperor penguins?” I could respond with confidence and satisfaction, “Yes.” Indeed, the eastern Ross Sea in late summer is probably the only time and place, apart from the colonies, where more emperor penguins can be seen than any other species of Antarctic bird or mammal (except perhaps the crabeater seal, which is the most abundant of all seals and perhaps of all marine mammals). In fact, we counted about ten thousand emperors in one limited area. I also saw many recently abandoned molting sites, which were obvious from the dense ring of feathers on the snow. And I found red-colored

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guano—evidence that my conjecture regarding the birds feeding on krill near the end of their journey was correct. The lightest emperor I found, just after it had finished its molt, weighed 16.5 kilograms. Even though the bird was at the ice edge with companions, I knew that it had not yet entered the water and begun to feed because a few old feathers were still dangling loosely on its back. Any swim would have dislodged them. When I weighed the bird, I noted that it was weak and docile, and it had a protruding breastbone. One never sees such a feature in emperor penguins. The only place I had seen such a condition before was on king penguins, which return to their colonies to molt. In fact, apart from emperors, the only other penguin that I know of that does not use the colony or nearby area to molt is the Adélie penguin, which also molts in the pack ice toward the eastern Ross Sea (although a few have been observed to molt on the shoreline near McMurdo Station). In the eastern Ross Sea, the penguins’ isolation is their safety net. Few predators are present, and there are no humans, either scientists or tourists. The difficulty in conducting a study on the molting journey explains why it has been done only once before, by Barbara Wienecke in 2000. The six birds she tagged and tracked from the Taylor Glacier and Auster colonies were on the outer rim of the Antarctic Continent, where the weather is warmer. When the birds left, the fast ice extended out 40 kilometers from the colonies. By the time Wienecke’s birds had finished foraging and fattening for the molt, the coastal ice regime had collapsed, leaving only pockets of fast ice along the coast. Like the Ross Sea birds, these emperors arrived at their molt locations (which were 157 to 567 kilometers away from their colonies) about a month after leaving those colonies. Although birds from the East Antarctic colonies do not have to travel as far to molt as those from the western Ross Sea, where they can molt is limited. In addition, when they foraged on their way to their molt site, they were in deep water of over a thousand meters and feeding mesopelagically (in the midwater column). Those depths may be less reliable than near the bottom for finding food and thus put the northern birds at greater risk of poor hunting. In comparison, the multiple banks running north to south across the Ross Sea continental shelf bisect the path of emperor penguins traveling from the western to the eastern Ross Sea. All are less than 500 meters deep. These may provide reliable foraging sites for Antarctic silverfish, much like the banks near the western Ross Sea colonies are reliable sites for the commuting penguins. If so, then the emperor penguins of the Ross Sea have feeding stations all across the shelf until they reach the deep waters of the

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eastern Ross Sea and Amundsen Sea. (It doesn’t sound any riskier than the light plane flying from San Diego to Tucson where the fuel stops are all known before leaving). Near their destination, they feed mainly on krill grazing on algae attached to the bottom of the pack ice. Thus, it seems that feeding risks are much lower for emperor penguins of the Ross Sea than for emperor penguins of the eastern Antarctic. The susceptibility of the northern pack ice and fast ice to disintegration earlier and more frequently during the hottest time of the year seems a more likely potential for failure to molt successfully. If that is the case, then penguins from more northerly regions, where most emperor penguin colonies are located, are more likely to experience population shrinkage. In fact, the only two large areas where reliable and multiyear sea ice occurs are in the eastern Ross Sea and the Weddell Sea. Less is known about the Weddell Sea, where few ships go and where few research stations exist. This is where Ernest Shackleton’s ship, the HMS Endurance, was trapped and crushed by ice in 1915, causing it to sink. Oddly enough, a new HMS Endurance carrying a crew of scientists entered the Weddell Sea in January 1998, in an unusually low ice year. They sailed into open water at 72° S that reached all the way to the Ronne Ice Shelf and across to the Antarctic Peninsula, at a latitude of over 77° S. That is about the same southerly range as the Ross Sea, only on nearly the opposite side of the continent. These scientists found dozens of molting emperor penguins on ice floes, mostly at 72° S. Many of the floes were between 500 and 2,000 meters in both length and width. The Endurance cruise took place the year before I went to the eastern Ross Sea, but I learned about it from the NOAA population estimator on the APIS cruise. Together, we surmised what colonies these Weddell Sea emperor penguins had come from and estimated that some had traveled 550 kilometers if they came from the Gould Bay colony, which is the most southerly emperor colony in Antarctica. Further estimates showed that nearly half of all known emperor penguin colonies have a close association with reliable pack- and fast-ice areas for molting. However, in 1973, based on satellite imagery, there was very little pack ice in the eastern Ross Sea. This was before emperor penguin distribution and population studies were being done, and it represented a missed opportunity regarding the effects such a reduction in pack ice might have on emperor penguins. From the meager evidence available, I believe the eastern Ross Sea and Amundsen Sea region is the molt home for just about all adults from the western Ross Sea and Amundsen Sea colonies. The remoteness of these ice floes serves them well to meet their need for minimal disturbance, as

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it cannot be reached by aircraft from any Antarctic station. It may be an essential habitat for the continued success of the high-latitude colonies of this region. However, for all emperors, the potential for a mass die-off seems possible. The steps leading up to such an event would be poor foraging during the journey to the molt area, and/or a much reduced molting area, such as the low amount of pack ice in 1973. The susceptibility of the birds to such an event is more likely the further north the molt area is located, such as on the northern rim of the continent in East Antarctica. Here the birds that Wienecke studied found refuge only near the continent where sea ice was protected from breaking up because of the configuration of the shoreline. They must therefore be more vulnerable to global warming in this phase of their annual cycle than the Ross Sea penguins. It is noteworthy that if there was ever a mass die-off at these sites, whether in the eastern Ross Sea or eastern Antarctica, it is unlikely to ever be noticed because the areas are so remote. Fortunately for the Ross and Amundsen Sea birds, much of the molt area has been designated as part of a Ross Sea Marine Protected Area (see chapter 12). This protection will be of great value for the conservation of emperor penguins, as well as for several other species that inhabit the Ross Sea.

[ Ch a pter 9 ]

The Post-molt Journey

A fight for love and glory, A case of do or die! Her ma n Hu pfeld

Once the molt is finished, emperor penguins face yet another journey. The breeders need to get back to the colony, and the nonbreeders need to go . . . somewhere. First, though, they all have to feed. The molt has cost them up to half their body mass, and some birds could be near to starvation. The breeders, in particular, have to pack on the weight if they are to breed successfully. Each female needs to weigh at least 30 kilograms when she arrives at the colony if she is to produce and lay an egg, and the males have to weigh about 40 kilograms to get through the winter fast while incubating it. Just like with the fledging chicks and the adults leaving the colony to molt, my question was: Where do they go? Until recently, this was entirely unknown. This is as true for Ross Sea birds as it is for birds anywhere else in the Antarctic. Even the bases near colonies in East Antarctica have only limited access to post-molt birds, which are scattered around in mostly unknown places along the northern coast. The problem, of course, is that gaining access to post-molt birds is very difficult. You need an icebreaker, and this is neither an easy nor cheap item to procure. The US Antarctic Program charters the specially built research vessel/icebreaker (RVIB) Nathaniel B. Palmer to support science projects in Antarctic waters. My first experience on this ship came in the austral winter of 1998, when chief scientist Martin Jeffries of the University of Alaska asked me to join him and his team on a cruise from April through the month of May to study sea-ice physics and biology in the Ross Sea. I jumped at the chance, because there was another question on my mind: Where do the females go after they have laid the egg and turned it over to their mate for incubation? Again, no one knew. Jeffries had held out the possibility that, conditions permitting, we could pay a winter visit to the

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Cape Washington colony. This would give me a chance to attach satellite tags to post-gravid females that were ready to depart. I asked one of my former postdoctoral students, Robert Van Dam, to accompany me. We cruised due south on the 180° longitude line from near Scott Island, a remote island at the northern edge of the Ross Sea, to the edge of the Ross Ice Shelf at 78° S, just 720 nautical miles north from the South Pole. That was the farthest south in winter that any ship had ever reached. It was a strange place, with the 30-meter-high shelf looming above us as we moved along a narrow band of open water in front of it. This is the so-called Ross Sea polynya. The camera crew went for a Zodiac ride up close to the shelf to get video of the ship in this far-out place. Robert and I went along to make hydrophone recordings to determine if any whales or seals were nearby, but we did not see or hear any. Working alongside the sea-ice folks during the cruise was extraordinary. The captain would push the ship up against sea ice so the scientists could disembark and take samples and measurements. At the same time, Robert and I would head out to search for marine mammals. Here we were, in the depths of winter, out on the sea ice for hours when the temperature and wind in combination occasionally exposed us to a windchill factor of more than −73°C (−100°F). In spite of these conditions, it was the most comfortable fieldwork I have ever done. The captain would turn the ship broadside to protect us from the wind, and we were heavily bundled up against the cold when we walked away from the ship to dip the hydrophone in the water and listen for seal or whale calls. When we returned to the ship, we knew we would have a chef-cooked meal, a hot shower, and a warm room and bed. Whenever the ship was underway, large spotlights lit the way to help the helmsman avoid striking large chunks of ice and small icebergs. Robert and I took advantage of that to look for and count every bird or mammal we saw as the ship passed through thin ice or channels in heavier ice. It was an amazing opportunity. A census to determine the abundance or lack of animals in the Ross Sea during the winter had never been done before. However, it meant watching for eight hours every day the ship was underway. Robert and I shared time on the bridge in four-hour watches. That was about the limit of our attention span before our observational detail declined. It is also way beyond the limit of the casual visitors that frequently dropped by to see what was happening and chat with us (unless the captain was around; then he was the center of attention). Also, since Robert and I were roommates, this schedule gave us some private time in our cabin when the other was on the bridge. At first, we saw plenty of Adélie penguins, a few emperor penguins, and

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a few Weddell seals, but once we were deep into the pack ice and into the Ross Sea, there was little to see. 6 From time to time everyone has an experience that they know will stay in their memory for the rest of their lives. These events can be either bad or good. Try as we might, the bad ones do not wash away, but the consolation is that the good ones remain as well. On May 28, 1998, I had a day I never want to forget. Sea conditions had been mild during the cruise, and we were near Cape Washington ahead of schedule. Jeffries offered to make a short diversion and give me two days to observe this large colony and attach tags in the depth of winter for the first—and probably last—time. The ship pulled up to the sea ice about four kilometers from the cape, and we set out with fifteen volunteers on a hike to the colony. It was the middle of the Antarctic winter night—twenty-four hours of darkness—with no moon. Hiking in the lead, I found that starlight was so bright reflecting off the snow that I could see where I was stepping fairly well without a flashlight. The surface was obscure, but I was confident the ice was good enough for the walk. Using a flashlight would have destroyed my night vision, and all the subtle aspects of the track would have been lost. To keep my bearings, the cape was my beacon: a big black rock that loomed in front of me like a black hole in the sky. Others insisted on using their lights, and when I glanced back at the strung-out hikers, they looked like a line of fireflies following me. My confidence in the integrity of the ice was challenged to a small degree when a Weddell seal rolled over just off my track and exhaled with a heavy sigh. Where there is a seal, there is a nearby hole in the ice, and I didn’t want anyone stepping into it. Onward we trekked, and as we approached the colony, my heart started beating faster. I could hear the penguins’ calls, and I began to see some stragglers. My level of excitement at this point is difficult to express. Except for Cape Crozier, no Ross Sea emperor colony had ever been visited at this time of year! (And because of Cape Washington’s relative inaccessibility, this was a much bigger deal!) It’s also possible that no one may ever repeat the experience. It was as though I had won the lottery! This was the scientific jackpot for an emperor penguin biologist, visiting Cape Washington in the winter! I finally sighted the compact crowd of the main colony. Several emperors were walking around in what seemed to be pairs, and many of the birds were collected in loose huddles. I thought that was odd, because the temperature was only −10°C (14°F). Surely they were not cold! I also noticed a lot of movement and bumping of birds into each other, and I thought

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perhaps those huddling might be doing so to protect themselves from being jostled and shoved off their eggs, but I was reluctant to push into the huddles to confirm this. I did confirm that there were no birds with eggs at the edge of the huddles. I concluded that few if any males were incubating eggs. In addition, there was a lot of calling back and forth, from both males and females. This was evidence that the birds hadn’t laid yet. If this had been the Pointe Géologie or Auster colony, most of the laying would have occurred already, the females would have departed, and the colony would be quiet. The only other winter studies of emperor foraging had been from Mawson Station in 1993 and Dumont d’Urville in 2005. The effort at Auster entailed tagging females after they laid their eggs, and tracking their movements over the next two months. This was a challenging task because the researchers had to travel from Mawson Station over 40 kilometers of sea ice in a tracked vehicle and camp temporarily in a small hut until the tagging was done. Then they returned in late winter to recover the tags. The study by French investigators at Dumont d’Urville was similar to the one conducted at Auster, though the French station is only 100 meters away from the colony. However, there are big differences between these northern colonies, which are at about 67° S (2,600 kilometers north of the South Pole), compared with Cape Washington, which is at nearly 75° S (only 1,700 kilometers north of the pole). This 900-kilometer difference is considerable. At Dumont d’Urville the sun sets for only nine days in June; at Cape Washington the sun sets for a full three months, May 7 to August 7. For a visual traveler like the emperor penguin, the difference in ambient light in the two different latitudes is like night and day. For the male in the Ross Sea, it’s not such a challenge, as he just sits with the egg on his feet until the sun begins to rise again, but the female has a long way to travel after laying if she is going to hunt in a region of civil twilight. I had brought along four satellite transmitters to attach to female birds if the opportunity arose, though I didn’t know how long they would last in the intense winter cold, especially with no solar input to warm them. I singled out mating pairs and selected the smallest bird of each, assuming

Civil Twilight There are three degrees of twilight after sunset: (1) civil, when the sun is 6° below the horizon, (2) nautical, when it is 12° below, and (3) astronomical, when it is 18° below the horizon. Beyond 18° is astronomical dark, or pitch black.

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that it was the female. (This was before it was found you could use feather samples to determine gender, though it would have been well after the fact in this case.) The birds’ travel after laying (if they were indeed females) would be interesting because of where they would go to forage during their two-month absence from the colony while the males incubated the eggs. Unfortunately, the results I obtained were ambiguous. All four remained in the colony for more than a week after being released. They were either nonbreeders or females that had laid an egg after we tagged them. After departure, three of the birds spent time near Crary Bank. One later traveled north and was near Cape Roget, 282 kilometers from the Cape Washington colony, when the signal ended on August 31. This covered much of the penguin’s winter sojourn, and the record indicates that there was no rush by this bird to get to northern latitudes and more light for hunting. During most of the journey, the sun was below the horizon and the bird was always in the dark. Did these birds feed during deep dives at Crary Bank, despite the winter night? Even during the bright summer, when they forage at the bank to catch food for their chicks, it must be very dark on the bottom at 450 meters. Sunlight would provide little or no help in finding prey, either on or near the bottom. Whether in the summer or the winter, the birds must therefore be relying on bioluminescence for detecting prey at depth. The advantage of the summer light is probably for finding a brightly lit hole or crack at the end of the dive. But how does a bird find a breathing hole in the dark? Perhaps bioluminescence and splashing at the hole from the activity of other birds in the water are helpful. If that’s the case, it would be in the interest of the birds to travel in teams during the winter. In the intense winter cold, flocking would also help keep fast-freezing holes open, and it would be advantageous during rest periods to huddle for warmth. I also learned something interesting during that short winter visit: there was a lot of sea activity before egg laying. This has never been observed at any of the northern colonies, and it will likely never be observed there because of the great distance between those colonies and the ice edge. Where we had hiked at Cape Washington, there were many penguin tracks, and we saw many birds in the water and around the ship. It seemed the only good reason for the comings and goings of these birds was to feed. Males feeding at this time would be hedging any uncertainty in their bet that they could fast for another two months before the females relieved them. The extra feeding provided a good opportunity to shorten their fast, from 120 days to about 70 days. This would make it possible for slightly underweight males to raise a chick successfully.

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Again, living next to an ice edge without a long march to water seems to be beneficial in terms of successful breeding. This may be part of the reason Cape Roget, Coulman Island, Cape Washington, and Cape Colbeck are so large. Another reason is the nearness of the productive banks mentioned earlier. However, the mystery remains about the types of dives these highlatitude emperor penguins do in the winter, and where they might occur. I was able continue my pursuit of what overwintering emperor penguins do in the Ross Sea on another cruise aboard the RVIB Nathaniel B. Palmer, from the third week of December 1999 to mid-February 2000. The primary purpose of this cruise was to census Antarctic pack-ice seals (the APIS cruise mentioned earlier), so I was on board as the only bird scientist. Near the end of the voyage, we pulled into Bartlett Inlet, Cape Colbeck, and while the seal folk were out counting seals, I was making observations from the whale-watch tower 20 meters off the water. From there I could look across the water to the top of the ice shelf, which was only slightly lower. On it were a group of emperor penguins, at the end of their molt. There was no obvious way they could have gotten up there. I figured there must have been a snow ramp when they arrived, about forty days earlier, and they had walked up this slope to molt on secure ice. The annual sea ice had melted or drifted away and now there was only open water next to the shelf. Were the birds trapped? I didn’t think so at the time (and still don’t), even though there was no way of leaving except over the side. There were several telltale tracks that led from the group of penguins across the shelf and over the edge. So not only are emperor penguins great aquatic divers, these remaining birds would become high divers as they returned to the sea! Later, we passed a solo emperor penguin on a small, flat iceberg with similar cliff heights on all sides. Sometime earlier, this bird had walked onto this berg while it was connected to the shelf. When the berg broke away from the shelf and sailed into the inlet, the bird went along as an unwitting passenger. There was no way off other than to take the plunge. Here was proof that emperor penguins get isolated on high icebergs from time to time. As global warming progresses and emperor penguins choose to breed more often on ice shelves, this circumstance of remaining on the shelf after the snow ramps have disappeared may become more common. There was no chance of tagging those emperors high on the ice shelf, but by early February, before we entered the inlet, I had tagged seven emperors. Three of them gave me useful information on their travels after the molt. By the end of February, two of these birds had departed the eastern Ross Sea and were at or in the vicinity of Cape Roget. They had left the

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Figure 9.1. A track of emperor no. 18902 from the eastern Ross Sea, where it remained in pack ice over deep water until early March. Most likely it fed on krill until a little later in March, when it moved over the Ross Sea continental shelf. By the end of March, 18902 was over the Ross Bank, and as it continued on its trajectory to Cape Roget it passed over Pennell and Mawson Banks. All of these could be fertile foraging areas. By April 15, no. 18902 arrived at the Cape Roget colony, presumably to breed. The bird never left pack ice during its journey. (Modified from Kooyman et al., “Moult Habitat, Pre- and Post-moult Diet.”)

deep waters north of the continental shelf and headed southwest onto the shelf in their journey to the western Ross Sea. This would give them access to the banks. One proceeded as far as 78° S latitude, near the edge of the Ross Ice Shelf, but by mid-April it was near the northern colonies of the western Ross Sea. The other remained east until early March and then followed a southwest track to about 77° S. From there, its most southerly position, it traveled on a northwest diagonal directly to Cape Roget (figure 9.1). Both these birds remained in pack ice for their entire journey. Penguin no. 18902 arrived at the Cape Roget colony on April 15, 2000, two and a half months after we tagged it. It weighed 23.5 kilograms when we first captured it, a little heavier than most of the birds in the area. If it was a female, she needed to increase her weight to about 30 kilograms by the end of her journey. If instead it was a male, he had to weigh nearly 40 kilograms when he arrived at the colony in order to survive the winter fast. However, based on my winter observations at Cape Washington, he could actually weigh somewhat less if he fed from the nearby ice edge at Cape Roget before the egg was laid.

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A third bird, no. 18901, traveled west along the edge of the Ross Sea continental shelf (marked by the thousand-meter bathymetry line in figure 9.1) until mid-March, when it turned due north, always staying within pack ice. When the signal from this bird ended in early June, it was loitering at about 69° S, north of the Ross Sea boundary. For unknown reasons, transmissions from the other tagged birds (which are not depicted) ended much farther south, close to their release in the eastern Ross Sea or Amundsen Sea. These records have exceptional value. They show that: (1) the birds had close association with sea ice; (2) they were always within a latitude where the sun continues to rise and set; (3) there was a marked difference between the track of what can be confidently assumed to be a nonbreeding bird and the two birds that traveled to the western Ross Sea; and (4) nonbreeding birds go north to an area where civil twilight occurs for a few hours daily. Because of the water depth there, they must be feeding from the surface to the mesopelagic zone, on prey that is not their main diet when over the Ross Sea continental shelf. I was encouraged by these results. However, in addition to icebreaker access to post-molt birds, I needed a tag that transmitted both position and dive data in order to get a clearer picture of the birds’ activities. Fortunately, this type of device was available in 2013, when I succeeded in getting space on the RVIB Nathaniel B. Palmer for another cruise in the Ross Sea. My team and I shared the ship with thirty microbiologists studying the lateseason phytoplankton bloom that happens there every year. The cruise, which began at McMurdo Station, offered me a rare opportunity to determine the distribution of seabirds and mammals in the Ross Sea during autumn, as well as another opportunity to investigate the post-molt behavior of the emperor penguins. Compared to the two previous cruises, this one was earlier in the year than my 1998 winter cruise and a few weeks later than the 1999/2000 cruise. As a result, we saw more penguin activity, for both emperors and Adélies. The latter were moving out into the pack ice to find suitable places to molt (and to hunt after the molt), and the emperors were just finishing their molt and either traveling to colony sites if they were planning to breed, or heading north if they were not going to breed. Crabeater and Weddell seals were all around in the newly forming sea ice, while killer and minke whales were doing late-season feeding before the ice consolidated and made it more difficult to travel in the Ross Sea. It was an engaging time for myself and my three team members, which included a biocomputer specialist, doctoral student, and postdoctoral student from my lab at SIO.

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Unfortunately, the ship’s itinerary was such that we arrived at Bartlett Inlet, Cape Colbeck in the eastern Ross Sea on March 14, which was too late for the exodus of post-molt birds toward their western colonies. No matter. I simply decided that we would tag eastern Ross Sea birds that would breed soon, and we deployed a few of the tags a short distance from the entry into the inlet. When the ship entered the inlet, I was surprised to find an extensive amount of fast ice. Normally at this time of year the inlet has open water, with a few icebergs and remnants of fast ice. It turned out that 2013 was an unusual year for sea ice all over the Ross Sea. I was also surprised to find a large flock of about a hundred emperor penguins resting on the ice there. From March 16 to March 17, we deployed the rest of the tags on birds with an average weight of 32 kilograms. In all, we tagged seventeen birds. Since the migration to the west had already occurred, I knew the birds we encountered resting in or near the inlet were likely local birds and would disperse differently. At least we would learn of their foraging travels before they bred at Cape Colbeck or other nearby colonies. I had high hopes! What came to pass was totally unexpected and at first very disappointing. We had somehow missed the breeders from the Cape Colbeck colony as well. Who would have guessed that all our tagged birds were nonbreeders? We thought surely some were there to stay. The records showed, however, that the tagged birds remained nearby for three weeks, feeding near Cape Colbeck and in the Bay of Whales not far away. In this area the maximum depth ranged from 370 to 460 meters, so they could have easily fed near the bottom. Finally, all the birds departed for the north in April. I could not have selected such an unusual cohort of only nonbreeding birds if I had tried! But in doing so, I had obtained an unusual sampling of nonbreeder activities during the winter. The experiment showed that without the usual constraints of breeding, the birds moved north with the sun. On this track, they seldom dived during the dark after civil twilight. In this way, they followed a similar travel and diving pattern to that of breeding females from the East Antarctic colonies near Mawson and Dumont d’Urville stations, which seldom dived after civil twilight turned to darkness. Soon after their departure from the Ross Ice Shelf, the emperors we had tagged were in deep oceanic water, similar to that encountered by the East Antarctic birds. For the rest of the winter and early spring, they fed at midwater depths, from about 50 to 150 meters. On the longest-lasting records, they were well beyond the Ross Sea and over the Southeast Pacific Basin. Only four birds continued to wear their transmitters until near the following summer’s molt. The average duration of the tags was 115 days. The

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longest transmission record was 323 days, for a bird that returned to near Cape Colbeck. Just like with the tags on fledglings, I speculated on why the transmitters stopped sending signals. Most likely the reasons for loss are different for the two cohorts. The fledglings were beyond sea ice when stoppage occurred. For them, the average period was 167 days, and the tags were of an earlier vintage and not expected to transmit much longer than they did. Also, they were attached less securely so they would fall off after the transmitter battery failed. In contrast, the nonbreeders from the eastern Ross Sea were always in ice, and the winter cold was getting intense. Of the many possibilities for the transmission ending, there are two possible and intriguing reasons. During fiercely cold spring nights, the transmitters iced up (figure 9.2). The added bulk would have made it easier for the birds to groom them off, or else scrape them off by swimming under the ice and rubbing the tag

Figure 9.2. A captive bird held at the Penguin Ranch corral for about two weeks in late October and early November. We attached a dummy transmitter to test the system while the bird rested within the corral and dived through a hole in the sea ice that we provided. (Photo by Robert Van Dam.)

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Figure 9.3. An emperor penguin thrusting through grease ice. Such a surfacing would place considerable drag on the bird, especially if a foreign body (such as a TDR) were attached. The birds may also break through even more completely formed ice, such as nilas (a thin sheet of smooth, level ice less than 10 centimeters thick).

against the under-ice surface. I also saw birds swimming near the ship crash through thin ice at high speed in order to breathe (figure 9.3). This may have been the most likely reason for transmitter loss. In summary, it is clearly difficult (and expensive) to access the pack ice from the deep south to the marginal ice zone during the winter, making it very challenging to elucidate the post-molt journey. However, the three studies I was fortunate enough to conduct and the data my team and I collected do offer some tantalizing clues. So what did we learn? Western Ross Sea birds make their way back to their respective colonies after molting, and it is likely that they take advantage of the Ross Sea banks along the way to fatten up for breeding. Without the long walk over fast ice to the colony, they may still be feeding when the northern East Antarctic birds (which are burdened by their long walk) have already begun to fast. This may contribute to the large colony sizes in the western Ross Sea, compared to those in the north. During my 2013 study of nonbreeders, I found that they spread widely but consistently to the north, and far enough north that there is adequate light to detect prey and ensure that breathing holes can be found on returning from a dive. From our ship observations and the closeness of all the satellite tracks, these emperor penguins also appear to move mostly as a flock. What the breeders do in the Ross Sea before and soon after laying is still

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Small Sample Sizes Astute readers will notice that my hypothesis regarding post-molt travel is based on small sample sizes, which is generally anathema in science. Unfortunately, gaining access to the emperors during the time of year necessary to gather data on this aspect of emperor penguin natural history is extraordinarily difficult, and sometimes impossible. It wasn’t for lack of trying. Three times, my former postdoctoral student Gitte McDonald and I submitted grant proposals for a Nathaniel B. Palmer cruise to the western Ross Sea in late January. The proposals failed because the icebreaker was not available at that time and place. The resumption of post-molt studies will have to wait until sometime in the future when an icebreaker is available in the eastern Ross Sea. For now, I feel that my hypothesis is reasonable. Much of bird behavior is genetically driven, such as when newly fledged birds know where to go when migrating over long distances. It is reasonable to assume that the travel characteristics of emperor penguins are likewise pre-programmed.

largely unknown. What we do know rests mainly on what we learned from the observations made near the ship when it was parked near the cape, and from four tagged birds from the Cape Washington colony in 1999. It is clear from those observations that the birds are active in the water in midwinter, and both males and females may be feeding. Because they are away for two months (the incubation time of the egg before hatching), post-gravid females may range the widest from the Ross Sea colonies, but they apparently do not reach the northern latitudes of the juveniles and nonbreeders, which means they are not in competition with those two groups. Nonetheless, the winter foraging habits of females from the high-latitude colonies of the Ross Sea remain a mystery in the life of emperor penguins.

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How Do They Do It?

For a large number of problems there will be some animal of choice, or a few such animals, on which it can be most conveniently studied. Au gust Kro gh, 13t h I n t er n at i o n a l Ph ysiologica l Congr ess Boston, 19 29

Anytime I think of emperor penguins, all kinds of superlatives come to mind: largest, deepest diving, longest breath hold. This go-anywhere bird thrives in places we can hardly imagine. Up until now we’ve talked a lot about how they routinely dive to depths that are extreme, not only for birds but also for many marine mammals. How do they stay warm, and how does their skin stay dry at those depths? How do they hold their breath long enough? How do they see to hunt? How do their organs deal with the pressure at 500 meters? That’s nearly fifty atmospheres! Put another way, that’s over 51 kilograms per square centimeter (730 pounds per square inch) over their entire body! It has to be an animal capable of extremes to live in such an extreme environment. Human divers exposed to high nitrogen pressure at depth suffer from something called nitrogen narcosis, an effect similar to being drunk. Emperors seem not to experience this narcotic effect. Humans, if they are not careful (and sometimes even when they are), can get decompression sickness (the “bends”), caused by nitrogen forming bubbles in the blood and tissues. Emperors decompress safely without having bubbles form in awkward places like the brain, blood, heart, or other places where bubbles are unwelcome. Emperors also don’t pass out from the hypoxia (low oxygen levels) that often result from their extreme dives. On top of this, somehow they manage to catch prey when diving deep into diminishing light after wandering around on sea ice under the brilliant Antarctic sun. How do they do these things? Let’s start with the feathers. Consider the long winter night, with the incubating males hunkered

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down to keep the egg at 37°C (98.6°F) while storms rage. Winds blow at 32 to 64 kilometers per hour in temperatures of −20°C to −40°C (−4°F to −40°F), which produces a windchill factor of around −84°C (−119°F). Even when it is calm, the ambient temperature may bottom out most conventional thermometers, and yet it gets so hot in their huddles that the penguins tend to break up to cool down. The scene in plate 16 can take place only in Antarctica. Here we have a large, relatively helpless prey sleeping soundly in the open, shielded from the fierce winds and cold by an exquisite coat of feathers. He or she is perfectly at peace in the wind, with not a care about the red-coated human stranger taking the picture only a few feet away. After all, in the emperor penguin’s long history there have never been any land predators to worry about. As for the cold, the sub-feather temperature was once measured in a resting bird during the Antarctic night, and there was a 69°C (156°F) difference between the skin and the outside temperature. That kind of insulation is why an emperor can sleep peacefully during a storm, with drifting snow accumulating over it. Not only does the snow not melt, it forms a sleepingbag-like cover. Resistance to the winter cold is easy to understand, though; you just need to have the proper outer wear, in this case an efficient feathered coat. (But still, they are barefoot!) The picture gets even more amazing when we consider what the emperor does for a living: It dives for food in the coldest water on Earth. Imagine wearing a suit that not only keeps you warm at −84°C (−119°F) but is also waterproof to 500 meters. The emperor’s feather coat does exactly that, much like a human diver’s dry suit. The emperor penguin has twenty-two types of feathers, which in total cover all the body except for the feet and the bill. They range in size from the long, rigid tail feathers (rectrices) to the minuscule feathers (coverts) that cover the leading edge of the wings and look like scales. Contour feathers, with some variation in shape and color, dominate the body. Each one has an after-feather, which is connected to the base of its shaft (figure 10.1), as well as an associated filoplume. Those tiny feathers have a long shaft and a small plume at the tip and are connected to sensory receptors in the skin. The most numerous feathers, which are four times as abundant as the contour feathers and so important for insulation, are the downy (plumulaceous) feathers. Because penguins were reported to have the densest feathers of all birds, a colleague and former student (Cassondra Williams) and I spent time counting them on three deceased adult emperor penguins I had collected at Cape Washington. The carcasses had been preserved in our laboratory freezer for years, waiting for an opportune moment.

(A)

(B)

(C)

Figure 10.1. Emperor penguin feathers. (A) is a ventral contour feather with an after-feather; (B) is a dorsal contour feather with an after-feather, and (C) shows dorsal and ventral down, or plumulaceous, feathers.

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Adult emperor penguin carcasses at Cape Washington are rare, and in the several seasons I spent there, I found only a handful of dead adults from the approximately forty thousand adults attending the colony each year. In one case, a slab of ice fell on a sleeping bird and held it fast until it starved to death. In another, we found a female frozen in place with her back hunched and her open beak jammed into the snow. It was a posture that suggested a painful death. On later examination, we discovered that she had died in the course of laying her egg. The lower part of her uterus had ruptured, and she bled to death. We found that dorsal (back) contour feathers numbered six per square centimeter and ventral (front) contours numbered nine per square centimeter. This is not the densest plumage. A small Eurasian bird called the white-throated dipper has plumage many times denser. Nevertheless, the emperor’s feather coat does its job quite well. The contour and down feathers are not only critical for maintaining body temperature in the severely cold environment of the Antarctic, they are also important for some less-conventional activities. During incubation, the male must keep the egg at approximately 37°C (98.6°F), even when the ambient temperature may be −40°C (−40°F). That’s a 77°C (170°F) difference! And it’s maintained across a gradient provided only by the contour and down feathers and the feet (which keep the egg off the ice). The penguin keeps its toes raised off the snow or ice and tucked into the brood pouch, a flap of feathered skin covering a patch of bare skin. Only a heel pad is in contact with the frozen surface. This pad is about the size of an American quarter, has no blood flow that could cause heat loss, and is constructed of air cells and keratin (the same fibrous protein that comprises hair, nails, and horns). Heat is provided by the vascularized skin of the brood pouch, which is in direct contact with the egg. Though the insulating properties described above are remarkable, they are easy to understand. Many cold-dwelling animals have effective insulation, whether it’s fur, fat, or feathers. The big question regarding emperor penguins is: How do their feathers maintain a thermal barrier when the bird is diving? On the surface, it is the air layer trapped by the down feathers that provides most of the insulation. When the penguin dives, water pressure compresses that air. At 500 meters, air trapped in the feather layer is compressed to about one-fiftieth of its original volume, resulting in very little insulating dead space. On top of that, the heat conductivity of water is about sixty times that of air. Without insulation, the flow of water as the bird dives would draw tremendous heat away from its body, especially since the water temperature at 500 meters in the Ross Sea is −2°C (28.4°F).

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Here is where the down feathers must play an important role. I speculate that the incompressible down nestled below the contour feathers is so dense that it’s almost like a layer of asbestos. It provides an insulating shield and becomes the main barrier for reducing heat loss. At the same time, the waterproof layer of contour feathers prevents seawater from reaching the skin. A rare, difficult-to-obtain measurement once found that at 90 meters, where any air space would be compressed to one-tenth of the surface volume, the under-feather temperature was still at 5°C (41°F). The feather coat performs a different function when the bird returns to the surface. Beginning at a depth of about 10 meters during the penguin’s ascent, a trail of bubbles streams from the feathers, forming a “contrail” similar in appearance to that created by a high-flying jet. An “air lubrication hypothesis” proposes that this stream of bubbles increases laminar flow over the penguin’s body and reduces drag, thereby enhancing acceleration during the final dash to the surface. In that short 10-meter distance, the penguin may reach a speed of nearly eight meters per second. The contrails also occur occasionally and briefly during descent and while the penguins are swimming horizontally. (The surprising reason for this is discussed in chapter 11.) Feathers provide other, unconventional contributions to the emperor. I mentioned earlier how they often toboggan, which allows them to move more easily, faster, and with less energy than if they walk. But I have never seen them tobogganing on ice, only on the soft surface of snow. Insulation from the breast feathers may be important during this activity, and perhaps that is the reason the contour feathers are denser on the chest than the back. Another reason for the added density of both contour and down feathers on the chest is to act as a cushion. All other Antarctic penguins that leap onto ice floes or fast ice (gentoo, chinstrap, and Adélie) land on their feet. Only the emperor lands on its chest, and never on its feet. The impact can be substantial for a 25-kilogram bird, and often there is a squeak when they land as some air in their air sacs gets abruptly forced out. You might say that on every landing, they get the wind knocked out of them. Speaking of wind, let’s discuss how the emperor manages to hold its breath long enough to dive to 500 meters and spend several minutes down there hunting for food. Emperor penguins are an extreme diver for birds. Their breath-hold ability, as in any other diving animal, depends on five interrelated factors: oxygen-storage capacity, level of aerobic metabolism (when oxygen is available), capacity for anaerobic metabolism (metabolism in the absence of oxygen), tolerance of low oxygen levels (hypoxemia and hypoxia),

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Feathers Feathers do more than keep emperor penguins warm. The yellow patches on the neck may be for sexual selection. The vibrancy of the patch may indicate the maturity of the bird, since birds with gray or faded patches, such as those of yearlings or slightly older youngsters, are of no interest to an adult prospective mate. The patch may also indicate some degree of body condition, such as health and vigor. Interestingly, emperors rarely exhibit color variations, which are the result of genetic accidents. When they occur, most if not all of them are maladaptive. Emperors have a uniformly black back. However, in the course of observing and counting tens of thousands of birds, we would occasionally see a bird or two per season with white patterns on its back. Most were seen at Cape Washington, but there were a couple of times when we saw similar anomalies on birds at Coulman Island. Rarest of all was a leucistic (white or colorless) juvenile, one of which we ran across when it was in the process of shedding its down feathers. The only parts of the bird that were not white were the pink feet and dark eyes. We saw the bird over three days before it presumably went to sea (plate 18). We also saw other color morphs in adults, such as black where there was supposed to be white or yellow, though these were only partial. I have, however, seen several all-black king penguins on both South Georgia Island and Isles de Possession, in the Crozet Archipelago. They are very handsome birds with their velvety black chest.

and tolerance of lactate (a potentially toxic byproduct of anaerobic metabolism). First and most straightforward is the oxygen store. In other words, what is the capacity of the fuel tank? Oxygen is stored in three main compartments: (1) the air sacs, (2) the blood, and (3) the muscle. The emperor’s nine air sacs are larger than its single lung and hold almost all the available air. For the average 25-kilogram adult emperor, that’s about three liters of air at the start of a dive, after a full inspiration. For comparison, the lungs of an average adult human, who is nearly three times the weight of the penguin, can hold only twice as much air, about six liters. As depth increases during a dive, the bird’s air sacs are compressed and gas exchange between the sacs and the lung declines. If the penguin reaches 500 meters, the air volume is only one-fiftieth of the original—basically going from a three-liter bag to a third of a measuring cup. Whether that third of a cup is distributed within the air sacs or lung is not currently known. Most likely it is sequestered in the air sacs and there is no (or very little) transfer of oxygen and nitrogen into the blood. This is probably a good

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thing, because otherwise there would be the risk of oxygen toxicity and nitrogen narcosis at such high pressures, and possibly nitrogen bubble formation if the bird were to ascend faster than two meters per second (their measured rate of ascent). During ascent, the air sacs expand with the reduction in hydrostatic pressure and gas exchange begins again, providing them with any oxygen that might remain. The second compartment is the blood, where oxygen is stored in hemoglobin (and, to a much lesser extent, in the plasma). Finally, oxygen is stored in the muscle, where it is bound to myoglobin. This last compartment is significant, and the muscles of deep divers tend to have high concentrations of myoglobin (which cause the muscles to appear much darker than those of terrestrial animals) and correspondingly higher levels of available oxygen. The myoglobin concentration in emperor penguin muscle is, at 6.4 grams per hundred grams of muscle, one of the highest of all diving animals. It is exceeded only by the concentration in the muscles of deep-diving marine mammals, such as the beaked whales (7.3 grams), the narwhal (7.9 grams), and the northern elephant seal (7.8 grams). Managing these three compartments of oxygen storage is the key to how emperor penguins can tolerate ten-minute dives to greater than 500 meters and/or dive durations of almost thirty minutes (in very rare emergencies). So how does this work? Oxygen in the lungs and air sacs is available only until those air spaces are compressed to the point that gas exchange with the blood either ceases or slows to a trickle, which means at the beginning and at the end of a deep dive. (It would generally be available during shallow dives.) The next step is aerobic metabolism. The higher that is, the faster oxygen is used up. One key to extending breath-hold time, then, is to reduce the metabolic rate. Determining the metabolic rate for an emperor penguin during a dive is technically impossible for us at the moment, but the bird certainly needs to have a sense of how fast oxygen is being used up and how long it can go before it exhausts all its diving resources. It’s like Charles Lindberg needing to know the rate of fuel consumption when making his momentous flight across the Atlantic. A mistaken estimate of gallons per hour could have resulted in an ignominious landing in the Atlantic. For the emperor the consequences may be as severe as well, especially when diving under ice. It is a mystery how they know their limits. Or do they? What we do know is that emperor penguins, like most diving animals, can and do slow their metabolic rate and conserve oxygen when diving. They do this in several ways, first by reducing both their heartbeat and, when possible, their level of effort. In preparation for a deep dive, the emperor hyperventilates, and its heart rate may rise to 250 beats per minute

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Figure 10.2. Stroke rate in 120 dives, all of them over 400 meters deep, from six penguins. The error bars are there because the dives are combined. Note that the variation is very low. (Modified from Williams, Sato, et al., “Muscle Energy Stores and Stroke Rates.”)

(bpm). It begins its descent with rapid and deep wing strokes to overcome positive buoyancy. Soon this slows to a continuous, steady beat as it gets deeper and the air under its feathers and in its lungs and air sacs is compressed to the point where the bird reaches neutral or negative buoyancy. At this point it sinks with little effort. By the time it reaches maximum depth, the heart rate has declined to an average of 17 bpm, and as low as 8 bpm—this despite the fact that the bird’s exercise level increases as the search for prey begins, and wing beat increases up to about 100 beats per minute (figure 10.2). During ascent, there is graded flow of blood to the lung. Blood flow to the muscle begins as heart rate rises, and by the time the bird surfaces, the heart is beating at over 180 bpm—two to three times higher than the resting rate. Stroke rate for much of the ascent is about thirty per minute. As the bird nears the surface, though, the rate decreases to the lowest level in the dive, at twelve strokes per minute, and in the final stage the bird simply glides upward, unless it is planning a fast exit out of the dive hole. Why would this be? One would think the birds would be in a hurry to get back to the surface and breathe. Certainly, once they reach a depth

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where the air in their feathers, lung, and air sacs has expanded enough to give them positive buoyancy, it doesn’t take much effort to continue upward. But is there more to it than that? Before we answer that, we need to mention another way in which emperors conserve their critical oxygen resources. In a process called shunt, they redirect blood flow away from the muscles and internal organs during a dive, saving it for the heart and the brain. So while these two critical organs rely on oxygen in the blood, there is little circulation in the muscles, even though the pectorals are working harder with the increased swim effort. And that’s where the third oxygen compartment comes in. Until it is depleted, the penguin relies on myoglobin to generate aerobic energy for its muscles. Cassondra Williams won the prize for best PhD thesis at SIO, as well as an award in the Journal of Experimental Biology for the best paper by a young investigator, for her work on measuring the oxygen dissociation curve of myoglobin in a diving emperor penguin. She found that the curve declined steadily, meaning the myoglobin was releasing its oxygen. After about five minutes, the myoglobin was out of gas, even though the oxygen bound to hemoglobin in the blood was still at a high level. So while the blood continued to release oxygen to the brain and heart, the muscles began to rely on energy metabolism without oxygen—anaerobic metabolism. The source of fuel in the muscle is glycogen. When oxygen is available, glycogen is metabolized (“burned”) completely, producing energy, carbon dioxide (CO2), and water. Without oxygen, it is burned incompletely, which produces lactate. The penguin’s breath-hold capacity is limited by its tolerance to hypoxemia (i.e., the oxygen available to its brain and heart), its glycogen stores, and its tolerance to lactate. Its ability to dive again is limited until oxygen is available to either burn the lactate or recycle it back to glycogen. The degree of limitation depends on the extent of the oxygen debt. Figure 10.3 shows a series of deep dives where such a debt occurs; the interval between each deep dive is the recovery period before another deep dive is attempted. It’s clear that deep divers pay a high cost for the dividend they get by hunting where few other divers can penetrate, and that cost is a long recovery time. Although oxygen replenishment is probably fast, as it binds quickly to hemoglobin and myoglobin, the recycling of lactate to glycogen is slow and requires several steps, which is most likely the main cause of long surface recoveries. In one particularly dramatic example, a tagged emperor surfaced from a dive and remained prone on the ice for six minutes, breathing heavily (starting at twenty-two breaths per minute and slowly decreasing to fifteen). It

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Time 8 hours

9 hours

10 hours

11 hours

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27

28

23

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Figure 10.3. A series of deep dives by an emperor penguin. Note the long recovery periods (twenty to twenty-eight minutes) after deep dives of eight-plus minutes. Where the zero-depth line is completely flat, it indicates that the birds are out of the water and on sea ice.

then stood quietly for twenty minutes, and it was more than eight hours before it made another dive. Later examination of the dive record revealed that it had just completed a 27.6-minute dive. Its resources must have been stretched to the limit. Thus, the behavioral and physiological evidence we currently have indicates that the emperor penguin’s extended recovery time after a long, deep dive is used to recycle lactate back to glycogen (though it may also be used as fuel in the muscle or other organs). The same would be true of any other deep-diving animal, such as some whales and seals. As marine biologist Nicola Quick and her team of whale researchers have written regarding extreme depth and breath-hold records, these animals “have evolved an unparalleled ability to deal with the by-products of aerobic and anaerobic metabolism, which allows them to exploit their bathypelagic foraging habitats.” They can say that again! Combining this ability with its immunity to extreme cold, the emperor penguin can access a food resource that no other diving bird and few marine mammals have a prayer of reaching. The other limits to dive duration are tolerance to hypoxemia and hypoxia. Hypoxemia is a condition where there is an abnormally low level of oxygen in the blood, either bound to hemoglobin or dissolved in the plasma. (The level of oxygen is called the oxygen tension or the partial pressure of oxygen, and it is generally expressed in millimeters of mercury [mmHg], as in how far a thin column of mercury in a tube would be dis-

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placed by the pressure.) Hypoxia occurs when there is an abnormally low level of oxygen in the tissues. Of course, what is abnormal depends on the animal. It was recently discovered that some deep-sea fishes survive at unusually low oxygen tensions in seawater, about 0.89 mmHg instead of the 150 mmHg in the oxygenated water at the surface. I suspect that they tend to be sluggish, as I mentioned in chapter 5 when describing why king penguins prefer to hunt in the day when their prey is deep, instead of at night when the fish are near the surface. If this is true, think of the advantage an active diving predator such as a seal or penguin has when they bring their own oxygen with them! It turns out that emperor penguins have a high tolerance for hypoxemia, and likely also for hypoxia. For example, if a human’s arterial oxygen tension declines from a normal breathing level of about 100 mmHg to 30 mmHg or less, the person tends to pass out. Yet the emperor penguin can tolerate an arterial oxygen tension of about 30 mmHg during dives up to twelve minutes. In other words, what is a dangerous level of oxygen tension in a human is fairly routine for an emperor penguin. So what is the purpose of all this information? In order to understand an animal’s ecology—how it survives to breed and how it fits into the greater scheme of things—one needs to know not only what it eats and how it finds and consumes that food (that is, its foraging strategy, or how it works in terms of the labor involved) but also how it manages these activities physiologically, or how it works in terms of the body’s internal mechanism. My whole career has been about these two definitions of work. In the case of natural divers, it is useful to know how much effort or energy foraging dives represent in order to understand their pattern. How much labor is involved in catching prey, and how much prey do the animals need to extract from the environment to maintain an energy balance? Both the Weddell seal and the emperor penguin are good subjects for this kind of research, because they both respond naturally to the isolated hole protocol (which I described at the beginning of chapter 5). The Weddell seal is particularly ideal because it dives for several hours with consistent dive and surface durations while feeding. It was during my work on them, using this protocol, that my team and I first developed the idea of the aerobic dive limit (ADL). As Paul Ponganis has said, “The aerobic dive limit has become the most fundamental concept in the interpretation of the diving physiology, diving behavior, and foraging ecology of marine mammals and diving birds.” The ADL is defined as the dive duration beyond which post-dive blood lactate begins to rise. In other words, it defines the point at which myoglobin oxygen has declined to a level where anaerobic metabolism in the

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muscle begins, producing lactate. As blood flow returns to the muscle at the end of the dive, the lactate is washed out of the muscle and enters the bloodstream. In my early work with Weddell seals, I had noticed that most of their dives were twenty minutes or less, with short surface intervals, whereas when they did longer dives, it seemed to take them longer to recover. Later, my colleagues and I were able to directly measure the peak lactic acid concentration in the arterial blood of several Weddell seal adults during their dive bouts. We found that when a dive exceeded about twenty minutes, there was a rise in the peak blood lactate. The longer the dive duration beyond this threshold, the higher the blood lactate. We concluded that beyond this dive duration oxygen becomes depleted and the production of lactate in the muscle increases, indicating a greater reliance on anaerobic metabolism, just as my earlier behavioral observations had implied. We applied similar procedures to experiments on emperor penguins and determined their ADL to be 5.6 minutes. In figure 10.4, one can 15

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Figure 10.4. Comparison of dive duration and peak lactate in emperor penguins and Weddell seals. (Modified from Kooyman and Ponganis, “Physiological Basis of Diving to Depth.”)

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see the correlation between dive duration and peak lactate for both the emperor penguin and the Weddell seal. Since emperor penguins frequently make deep dives that last up to ten minutes, they join an exceptional cadre of divers that willingly exceed their ADL in order to reach prey at extreme depths. There aren’t many animals in this somewhat exclusive group, but Cuvier’s beaked whale (Ziphius cavirostris) (also known as the goose-beaked whale) is one of them. This reclusive, six-meter-long cetacean has been measured diving to 2,990 meters (almost two miles!) and holding its breath for 222 minutes (over three and a half hours!). It is currently impossible to measure blood lactate directly in these animals, but evidence that they have exceeded their ADL is based on the long recovery times observed between dives. Because of the emperor’s small size, high oxygen consumption rate while diving, and relatively small oxygen stores (about 68 milliliters of oxygen per kilogram of body mass, compared to the deep and long-diving elephant seal’s 100 milliliters per kilogram), these birds have no choice but to exceed their ADL if they want to reach deep-dwelling prey. It is reasonable to conclude that the foraging success of a deep dive makes it worth all the effort and physiological stress. Finally, there is one other aspect to the deep-diving lifestyle of emperor penguins that we need to discuss. It is dark at 500 meters. In fact, it’s probably safe to say that it’s devoid of sunlight, because the standard definition of the oceanic aphotic (without light) zone begins at 200 meters. In those conditions, whales can use echolocation to locate prey. Seals have been observed using their vibrissae (whiskers) to detect motion in order to locate prey. Emperor (and king) penguins have neither of these tools. They are almost certainly visual predators. How, and what, do they see down there? Sometimes during quiet times in the field, or even when I was back at the lab analyzing data, I realized there were mysteries as interesting as the original problem that I was pursuing. This is one of them, and it has been on my mind for a long time. Are the deep dives of emperor penguins really without light? I know from my past studies of Weddell seals in McMurdo Sound that, looking up, one can see a crack in two-meter-thick fast ice from a depth of 300 meters. It might be possible, if an animal has big enough eyes with sufficient sensitivity and light-gathering capacity, to see the silhouettes of prey by swimming below them and looking up. In fact, seals’ eyes are perfectly oriented to allow them to hunt this way. Finding camouflaged prey near the bottom at 400 to 500 meters, as the emperors do, is altogether different and presents a much greater problem. At 200 meters (and beyond), the only light penetrating is in the blue spectrum (about 475 nanometers), which is close to the most sensitive

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range of the Weddell seal’s eye. Most likely this is the most sensitive range of the emperor penguin’s eye as well. What might be underappreciated is the size of the emperor’s pupil, which dilates from a pinhole to an opening that occupies the whole visible part of the eye. (The same is true for the king penguin—plate 17.) This feature is seldom seen because the most common experience for people working with emperor penguins in the wild is on a flat plain of snow during brilliant sunlit days. The eyelids and feathers cover the entire eye except for the 1.5-centimeter-diameter iris, making the eye appear deceptively small. In fact, behind this iris is an eyeball that is about half the size of the brain. The emperor’s eye is even quite large compared to the entire head (figure 10.5), and the two eyes combined occupy about the same volume of space in the skull as the brain (figure 10.6). There is a well-developed rete mirabile at the base of the eye where the optic nerve exits the orbital fossa. This may help keep the eye and optic nerve warm as the emperor swims through −2°C (28.4°F) water with its eyes wide open.

Figure 10.5. Frontal scan of emperor penguin skull showing the size of its eyes in relation to the skull. (Computer tomographic image courtesy of Miriam Scadeng, associate professor, University of Auckland, New Zealand.)

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Figure 10.6. An MRI of an emperor penguin’s brain and eyes. The volume of both eyes combined is 48 milliliters, and the brain volume is 44 milliliters. (Image and data courtesy of Miriam Scadeng, associate professor, University of Auckland, New Zealand.)

Emperor and king penguins also have a tapetum lucidum, or eye reflector. Light passes through the retina, then reflects back along the same path, significantly increasing the amount of light stimulation to the retina. This is a common adaptation for most mammals and nocturnal birds. It is the reason for the “deer in the headlights” phenomenon, or the shiny reflection one sees when aiming a flashlight at a cat or a raccoon at night. In short, the eye is large, is protected from the cold, and has a large aperture. These are expected attributes for a visual animal that operates mostly in the twilight zone of the sea. In addition, much of its time during breeding is spent in the twenty-four-hour dark of winter, so extremely efficient light-gathering organs are an important adaptation all around. In fact, if you consider all their attributes—silently hunting elusive prey in the dark, with large, highly light sensitive eyes—it seems to me that emperor penguins should be thought of as marine owls. That brings us back to the overriding question: How do they hunt

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Rete Mirabile Rete mirabile is Latin for “wonderful net.” It is a complex of multiple intertwined arteries and veins, all of which lie very close to each other. The structure conserves body heat by permitting the exchange of heat between the two elements of the circulatory system, warming venous blood on its way back to the heart from heat in the outflowing arterial blood in a process called countercurrent exchange.

successfully near a deep ocean bottom or during the winter night? The two problems are different. Finding prey at night may be enhanced by bioluminescence. If, as is well established, 95% of marine fish, phytoplankton, and zooplankton emit light, then it is logical to assume this light may be a more important factor for the emperor than light from the surface. But then, why is it that emperor penguins hunting offshore during the winter night tend not to dive beyond civil twilight? My friend and fellow penguin researcher David Ainley postulates that Adélie penguins don’t dive at night due to fear of predation. That may be true of emperor penguins as well, but I think they have a bigger problem. Emperors are accustomed to diving in pack ice, which tends to move with the currents or wind. During the interim between entry and exit, such as when a bird is on a long, deep dive, the hole it had used to enter the water could close. Evidence that emperor penguins do sometimes lose track of breathing holes is when we see dives longer than twenty minutes, such as in the example I mentioned earlier. This could happen when visibility is low, like at night. Unlike prey that emits bioluminescence and gives away its location, a dive hole does not luminesce, and it may not be apparent on moonless or cloudy nights, or if drifting snow covers it. In short, emperor penguins may be reluctant to dive at night for fear of drowning. Much of the physiological and metabolic information we have on emperor penguins comes from experiments conducted by Paul Ponganis and his graduate students at the Penguin Ranch, as well as our studies on freeranging birds at Cape Washington. At the Penguin Ranch, we kept the birds in a corral and released them every day to a hole in the two-meter-thick ice so they could dive and feed. Initially, we had to train them about the corral and the dive hole, as well the extra holes we had drilled around the corral in case a Weddell seal commandeered the primary hole. Over time, they came to understand that they were allowed to dive from early morning to early evening. It also took a bit of training for them to allow us to easily take measurements and samples, without which our experiments would not be technically possible. For the

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first few days of introduction, we fed them previously caught fish, but soon they were on their own and catching borks under the ice. 7 We had the underwater observation chamber, which I mentioned earlier, installed at the ranch so we could watch the birds in the brilliantly clear water of McMurdo Sound (figure 10.7). Even though visibility ranged from 100 to 200 meters, we lost them when they went deeper than 50 meters because of their black back. Despite that, the chamber was the best place for underwater observations of penguins I have ever experienced. Like everyone who either worked at or visited the ranch, I spent hours in there. The viewing windows were about five meters

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Figure 10.7. Our underwater observation chamber. One could take photographs or videos of the under-ice environment, as this occupant is doing. (Photo by J. Mastro.)

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below the water surface, and I could sit there watching the action. I could observe how they managed their diving and how they interacted with one another below the ice, and I could check on how the TDRs were riding on their backs. It was a quiet time, alone in the chamber, ideal for thinking about the birds. In other words, daydreaming was frequent. I had to agree with my French friend Yvon Le Maho, after he returned to the surface from a stint in the chamber, when he said it “was worth the whole trip to the Antarctic.” 8 Having the penguins at the ranch also gave us the opportunity to dive with them, and in fact they were allowed to dive only when a dive tender was present, in case a seal came to harass birds or if the hole began to ice over. They accepted us ungainly, bubble-exhaling humans without avoiding us and without any apparent deviation from their diving routine. One of our favorite times of the day was the morning release. At that time, all fifteen to twenty birds would be leaning on the gate we used to separate them from the dive hole at night. Typically, before we gave the command to release the birds, one of us would be down in the chamber to watch the stampede into the water, an event we called “penguinfall.” It was spectacular and invigorated me for the rest of the day. We learned a lot about the emperors at the ranch. We already knew from our work at Cape Washington and other colonies that long dives of more than fifteen minutes occurred while the birds were diving under dense pack ice. We surmised this was because ice movement might have closed the hole or crack they had used to enter the water, especially when our instruments recorded long dive profiles with an early deep segment followed by a long shallow period. We assumed this was because the bird was searching for another breathing hole. At the ranch, we got an example of how adaptive they are in navigating the ice. During one of our experiments, when several penguins were diving from the hole, five of them did not return in the usual time. We anxiously searched the horizon, and to our joy and surprise we spotted them about a kilometer away. They were walking away from a seal hole and toward the ice edge, which was 10 to 20 kilometers to the north. Presumably they had spotted the hole during a deep dive, because in the clear, ice-covered water of McMurdo Sound, any opening in the ice can be visible from a considerable depth. We stopped letting other birds dive in the hole and drove out to the escapees, who were still marching north. We brought them back and let them dive one more time in the hole. They navigated their way right back to the seal hole, which assured us that they had no intention of coming

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back to the ranch. We bid them farewell and proceeded with our work on the other birds. We were confident that none of the other penguins had spotted the seal hole and were unlikely to find it because of the distance from the ranch. We were correct, and our studies went on for another week without another escape from the corral. When we released the rest of the birds, they had no hesitation and left on a direct track to the north. They did not even take a moment to thank us for all the fish we had given them.

[ Ch a pter 11 ]

Predator as Prey

You can observe a lot just by watching. Yo gi Ber r a

Although it wasn’t the focus of my research at Cape Washington, I hadn’t been there long before I began to take a keen interest in the interactions between emperor penguins and their primary predator, the leopard seal (Hydrurga leptonyx). Leopard seals are imposing animals. They are the second largest of all Antarctic and sub-Antarctic seals, with a length up to 3.5 meters and a weight of 400 to 600 kilograms. Their most striking characteristic is their disproportionately large head, one of the largest of all seals. The mouth is exceptionally long, with large canines and complex molars that allow them to strain seawater when they feed on krill. When the mouth is closed, it presents a reptilian impression of a smile, and when it is open, the gap is so wide that the teeth are well exposed and intimidating (see figure 5.6). Countershading gives them a solid blue-black back and a beautiful silvery undersurface with scattered spotting. The elaborate interaction between the two species, with potentially dire consequences for the emperor, is just as important an element of the birds’ natural history as their diving behavior and physiology. Over the course of twenty years and nine seasons, my teams and I spent more than a thousand hours observing this relationship, both above and below the water. Over a sample three-year period, we observed eleven kills of adult penguins. This was a rate of one kill for every seventy hours of observation. In other words, seeing a kill event required time and patience. When one occurred, though, it was filled with excitement, surprises, and sometimes a close call for the observer. When I began work at Cape Washington in 1986, no one had ever witnessed a leopard seal killing an emperor penguin. Access to emperor col-

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onies is so difficult that, to my knowledge, few have observed this event (if indeed anyone at all) except my team members and myself. Knowing that no one else has seen the things we witnessed is one of the most aweinspiring aspects of this experience. We were in one of the most isolated and difficult places to reach anywhere in the world. Far fewer people have been to the Cape Washington ice edge than to the top of Mount Everest. Perhaps that isn’t saying much these days, but what about the moon? Since Neil Armstrong set foot there in 1969, there have been only eleven others. Not many more than that have spent enough time camped at Cape Washington to observe emperors and seals interacting. My purpose for this informal study was to observe as many aspects of predation as possible and record the various tactics employed by both the seals and penguins. This was strictly an adventitious and descriptive study. We never interfered in or attempted to manipulate the situation, nor did we keep records of capture rates or levels of success. Doing so would have conflicted with the main reason we were at Cape Washington, and it would have required far more time and manpower than we could muster. Nevertheless, through our observations we learned a considerable amount about the needs and problems of both species. At first it just required walking along the ice edge and sometimes waiting at some high-activity points along the way. We also made underwater observations, but I’ll start with what we saw from the surface. To understand the interactions between these two species better, one needs to appreciate the environment in which the majority of them occur: the ice edge. The leopard seal has no chance of chasing down a tobogganing emperor on the relatively flat surface that characterizes most of the fast ice in Terra Nova Bay. Nor can it outswim or outmaneuver a penguin in open water. It’s only at or near an ice edge, whether fast ice or a floe, where the emperor is most vulnerable, and where the seal has much chance of success. A lot of that has to do with the topography of the edge. It is a dynamic environment. At all times, from its formation in the winter to its dissolution in the summer, the ice edge is subject to the effects of temperature, wind, waves, and grounded icebergs, which can act as a shield to storms. A perfect edge is where solid fast ice (typically about 20 centimeters thick) abuts open water. This arrangement is the exception rather than the rule. Newly formed ice only a few centimeters thick may create a seaward extension to the fast ice that is either broken up by storms or becomes thick enough to resist break-out until the summer melt. Winter or spring storms may drive ice floes into the edge, rafting them up and creating what we

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called a “rubble pile,” which could be several meters thick. This condition was often the case if the edge location was old. Occasionally, new ice would form seaward of the rubble pile, creating a new edge. Like all floating ice, most of the sea ice lies below the surface. The distance between the water and the surface of the ice is called the “ice foot.” At the edge of 20-centimeter-thick fast ice, the foot is only a couple of centimeters. For newly formed thin ice, the foot is negligible. When there is a rubble pile of rafted floes, the ice foot can be over two meters. The actions of the birds can also affect the ice topography, sometimes not in a good way. The emperors would often use a hole in the ice to access the surface. Large numbers of birds using a single dive hole had both benefits and a liability. Around-the-clock use keeps the hole from freezing over—a clear benefit. However, because of the entrained water carried onto the ice by emperors exiting continuously, the area around the hole would turn into a large bog of slush ice. Some of the splashed water would formed a raised, frozen edge around a slushy pool of water. Within a few days, the ridge would be about half a meter high and the bog itself half a meter deep. The bog would have a large central pool next to the exit hole, with narrow channel extensions that the birds created by their fast tobogganing as they scrambled through the slush to get onto firm ice (plate 19). When the bog was deep and fully formed, the birds were unable to escape from it quickly, and sometimes they gave up and dived back down the hole. Because of these difficulties and how the bog compromised their rapid escape away from the hole, we called the bogs “death pits.” This, then, was the environment through which emperors navigated on their “commutes” to and from the sea, which of course they had to do in order to feed their chicks. It was a dangerous place, and we saw just how dangerous on several occasions. The penguins form large aggregations near the ice edge before departures, perhaps based on an instinctual knowledge that moving in groups reduces individual risk. The flocks were loosely organized and likely the result of single birds marching or tobogganing toward the ice edge, joining together with others doing the same, and finally joining birds already at the edge. In this way, a group would grow to become a flock of twenty to two hundred birds, depending on how long they waited before plunging into the sea (plate 20). The largest gathering I ever saw was at Coulman Island, where about four thousand birds crowded together before they all departed in one steady passage into the water. The process took about four minutes. Leopard seals stalking the ice edge take advantage of this behavior to grab a surprised penguin, a technique we called the “leap and snatch.” We saw this technique only twice, but it is over so quickly that it would likely

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not be witnessed often, even if it occurred frequently. Both times it was a powerful moment. The lead bird of a group was charging forward to the water, either by walking or tobogganing on its belly. The seal determined where the bird would be, lunged out of the water, grabbed it before it could react, and fell back into the water with the bird in its jaws. It was over in an instant. All the penguins that had been following the lead bird reversed direction in a panic, and what once had been a tight group was now scattered across the ice. This is probably why emperors seldom stand closer than two meters from the water’s edge. The ice edge is equally dangerous for emperors returning to the colony from their foraging trips. Arriving birds formed flocks similar to those that were departing, and there could be a few dozen or a hundred in the flock. If there was open water at the edge, the penguins approached slowly to within 50 or 100 meters then circled back and forth for a while, making shallow dives. Keep in mind that the arriving birds had been on a foraging trip of a week or more, and the ice edge would have changed in the interim. It therefore required some inspection of its condition. The penguins were likely also scouting for the presence of leopard seals. After a while, they either moved away from the edge, moved along to another spot, or in near unison approached the exit area and accelerated up and out of the water. Their exit was either through a penguin hole, if thin ice had formed, or over the edge’s ice foot. Most of these ice foots were less than a meter, but occasionally the birds would clear an edge that was about two meters high. 9 One does not think of the heavy-bodied emperor penguin as a flier, but they are at times. If the ice foot was high, they came rocketing up to the surface and launched into a short flight to clear the edge and land on the ice two to three meters back (plate 21). Granted, it was a short flight, but it was important. Those that did not clear the ice foot fell back into the water and were an easy catch for a pursuing leopard seal. 10 Using an equation to determine the maximum height the penguins could leap, we calculated that at their maximum measured speed of 7.7 meters per second the birds could reach a height of 2.5 meters. I saw that high a leap on a few occasions, and sometimes it was not associated with a high ice foot. In fact, when we saw emperor penguins leap to a height of two meters when coming ashore, even with a low ice foot, look out for killer whales, and voilà, they soon appeared. For me, these were epic moments in our ice-edge observations. Another factor seemed to be proximity of leopard seals. If one was nearby, the arrivals were very fast and the leaps were high and long, fol-

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lowed by frantic tobogganing across the thin ice (if present) to the fast ice. I assumed that with casual arrivals—in which there was slow surfacing and breathing near the ice edge, and when the birds used short, easy leaps onto the ice—they were confident from their underwater survey that there was no leopard seal nearby. The best conditions for the penguins were a clean fast-ice edge with a low ice foot, or else a tongue of new ice that was thick enough to support the bird but too thick for a leopard seal to break through from below. A rough ice surface was not only undesirable but downright hazardous. As beautiful as emperor penguins are, they cannot move gracefully on uneven ice. In fact, they are about as clumsy as a person wearing street shoes trying to negotiate a sleet-covered sidewalk in a strong wind. In addition, emperor penguins cannot run. Their skin and feathers extend down to the top of their feet, so when they try to move rapidly it is akin to a person trying to run with his pants down around his ankles. In these conditions, a leopard seal chasing a penguin had the advantage, as the seal could move more quickly on the rough ice. In the literal end before it was grabbed, the bird would flop on its belly and try to toboggan across the ice, but it was like trying to skateboard on a boulder-strewn road. The last-ditch effort often ended in failure. Until returning penguins made it well past the ice edge, they still weren’t safe. Sometimes a seal would lurk on the ice next to the edge, waiting for arriving birds. For the seal, selecting the right spot was easy, because emperor penguins tend to arrive at edges that are usually not high above the water, and where the surface relief beyond the edge is low. These favored sites were made obvious by the regular arrival of birds. Until 1993, we had not seen this strategy and wondered why it wasn’t used. That year, two seals satisfied our pondering when they adopted this method with great success, so much so that they grew fat. Up until this time, I had never seen a fat leopard seal at Cape Washington. They were usually slim and lithe, with the large head dominating their profile. These two looked more like rotund Weddell seals, though the head was still prominent. Once I saw one of these fat seals arouse from a sound sleep, move the short distance to the ice edge, and capture a bird within twenty minutes. The catch was spectacular. A small group of birds was arriving in the usual fashion, leaping onto the ice. After two lunges and misses, one in which the bird landed on the seal’s back, the seal grabbed the third bird in midair. With its head almost as long as the meter-long emperor penguin, it grabbed the bird by the chest and stopped the flying penguin midway through its leap to shore. Even though the penguin’s condensed mass can

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be compared to a 25-kilogram sack of sand, the seal’s neck did not even flex when it stopped the flight of the penguin. After the catch, the bird went completely limp and the seal took it into the water without a struggle, not even a wing flap (plate 22). 11 This reaction of the birds after they were captured, where they didn’t put up any struggle, was initially surprising to me. In another observed capture, the seal held on to the penguin for thirty minutes, during which it took the bird underwater numerous times. However, it always brought the penguin to the surface so its head was above water and it could breath. This may have not been intentional but rather simply because the easiest place to grasp the bird was on its neck. During this whole episode, the penguin never struggled, but made only feeble wing movements. At times it was difficult to tell if it was still alive. When another leopard seal approached, the first seal relaxed its grip and the penguin rocketed away and up onto the ice. I inspected the bird and it had only minor puncture wounds. Meanwhile, the seals took no notice, as they appeared to be arguing over property rights to the capture site. We had seen numerous wounded birds in the area and initially wondered how they escaped the jaws of the leopard seal once they were caught. We decided that the quiet behavior of the bird, in which they go limp once caught, may sometimes catch the seal off guard. In a moment when the seal relaxes its grip, perhaps because it thinks the bird is dead, the penguin breaks away. The behavior also helps a penguin conserve oxygen when it is held underwater, which confounds the seal’s technique of trying to drown the bird. I have the impression that under these circumstances the penguin can hold its breath longer than the seal. One of the most dangerous places for the penguins was the “death trap” ice bog. A leopard seal would sometimes rest in the bog and wait for the birds. This would have worked better had the seal not persisted in peering down the exit hole. The birds could see it as they circled below, and after a few orbits they would go to another hole. It was like a polar bear trying to sneak up on a ringed seal by casually walking across the snow-free ice and expecting the seal to remain out of the water. The seal was much more successful when it followed the penguins into the ice bog, where it could move more quickly than the birds. We saw this behavior just once, but bloodstains around the hole suggested that kills had occurred in this way several times. Eventually the birds began to exit in another direction, where they could land directly onto firm ice. This tactic lasted until these tracks also formed pits. Seals were seldom successful at leaping onto the ice and chasing birds where no bog existed. In contrast to the challenges in capturing adults, catching chicks dur-

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ing fledging was like picking apples off a tree, whether the chicks were in the water or at the ice edge. If chicks were in the water, it was just a matter of swimming up and grabbing them. The clumsy birds were experiencing water for the first time and flailing with minimum efficiency. They were still 60% covered by down feathers, which was another encumbrance besides their poor wingbeat technique. On top of that, they were calling constantly, like ringing the dinner bell. We saw a leopard seal take one about every thirty-six hours that we patrolled the ice edge. As for chicks near the edge and still on the ice, it was easy for the seal to lunge out of the water and grab one. One capture was so easy that the seal seemed to discriminate about body condition and reject one chick for being too thin. The young bird was treated so gently that there was no apparent physical damage. In another instance of easy capture, the seal played with the chick like a cat with a mouse. Finally, it left the poor chick exhausted on an ice floe, but again with no apparent physical damage. Sometimes, if the chick was not too far from the edge, the seal would just chase it down. These surface chases at the water’s edge were the chicks’ first experience near water. Some introduction! They were confused about the seal, and panic ensued as soon as the seal moved toward them. In their rush to get away from the seal, they stumbled over the uneven surface and each other, but they were reluctant to try a water escape. That was a wise move, because until the chicks shed their down and developed their swimming skills, they were defenseless against leopard seals. The survival strategy at a large colony, such as Cape Washington, was to congregate at the ice edge and depart in large groups, swamping the predators, and then leaving the area as quickly as possible. The intensity of swamping was illustrated by the fact that in less than two weeks 90% of the twenty thousand or so chicks from the Cape Washington colony would have departed. Clearly, the three to five leopard seals frequenting the area would be unable to eat enough chicks to have much effect on fledging success. Since no great concentration of chicks has ever been seen at sea or in the pack, it is likely that not long after they distance themselves from the colony the chicks disperse into groups of a few birds. It goes without saying that making these observations presented certain hazards for us as well as the birds. The encounters we had demonstrated the seal’s basic strategy of surprising prey by leaping suddenly onto the ice or breaking through thin ice. Over three seasons of observation at Cape Washington, we kept track of every incident and logged thirteen threats against humans. Six of these were leaps onto the ice near where an observer was standing. Fortunately, there was no real chance for actual contact in these cases because humans are much more agile on land (and ice).

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In one case, my son Tory and I were out at the ice edge. I had cut a hole through some thin ice a short distance beyond the thicker, main edge so we could lower a video camera into the water. There was a penguin hole nearby and we were hoping to get underwater footage of the birds coming up through the hole, as well as surface photos of them piling onto the ice. A seal poked its head up just off the edge of the thin ice and looked at us for a moment before resubmerging. The next thing we knew, the seal came flying out of the penguin hole. It must have gone to top speed after it saw us, because it came right out of the water without touching the edge of the hole and just kept right on sliding across the ice toward my son. Tory scrambled away, dropping his camera and diving behind a ridge of piled ice for refuge. When it was clear to the seal that it wasn’t going to catch anyone, it just sat there for a while and watched us. Then it slid back into the water. After the seal retreated and Tory emerged, I couldn’t help but tease him a little. “Did you get the photo?” I asked, following up with, “That was my lens you dropped.” His look conveyed his annoyance. There were a number of incidents like this, including one where a National Geographic photographer visiting Cape Washington got his camera broken. The photographer had just set up his big video camera on a tripod to get close shots of birds coming out of water. Instead, a leopard seal came flying out of the water. The photographer fell backward and scrambled to get away. The seal bit the tripod and it fell over. The camera landed right on the big expensive lens and damaged it. Perhaps leopard seals do not like to be photographed. Despite our close calls, none of us was ever injured. I believe this was due more to our skill and our understanding of seal behavior than to luck. Others have also had close calls. A few years ago, a marine biologist was kneeling at the edge of the fast ice in McMurdo Sound and collecting water samples when a leopard seal lunged out of the water, bit her on the knee, let go, and fell back into the water. This may have been a case of mistaken identity, as her shadow on the ice may have resembled a penguin from below. The seal was probably as surprised as she was. In most cases, even the one where I felt at serious risk, leopard seal lunges toward humans seemed to be more feints than actual attacks. Possibly humans are viewed as competitors for a common resource, and the seal is expressing territorial behavior. I propose this hypothesis because of certain characteristics of leopard seal behavior. First, we seldom saw seals together, and only in passing, but we knew from identifying marks on their chests that there were at least three or four seals routinely hunting penguins in any given season. Second, once when

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a “visiting” female seal had finished resting on the ice after several hours, she was prevented from entering the water by another seal. The local seal harassed her for about thirty minutes, and she appeared reluctant to dive. Eventually she did enter the water and was never seen again. Third, the seals call frequently underwater and at times almost continuously, as if they are announcing their presence. Such vocalizations suggested to us a means of establishing a hunting space, but it still left me wondering about the efficacy of the calling, because penguins are not deaf. In our first season at Cape Washington, in 1986, we realized we were missing a lot with just surface observations and wanted to see what was going on underwater. Our only means of solving the problem for that season was to cut a hole in the bottom of a small barrel and glue a piece of plexiglass in the hole. In this way we could push the barrel about 20 centimeters below the surface and see the activity just in front of the ice edge. This procedure required that the fast-ice edge was no more than 30 centimeters thick, because at this thickness the ice foot was only a few centimeters. What we saw through this window was limiting, but it was much better than just standing by the edge and peering down through a smooth interface. We could see penguins whizzing around and leaving contrails. Soon we realized we could put a video camera in the barrel (our “camera in a can”) and get a video record (figure 11.1). In order to do this, one of us would lie flat on the ice surface and hold the camera while the other sat on the cameraman’s backside. This not only helped stabilize the barrel, but it also kept the cameraman from falling into the water. To anyone standing nearby, it must have made a laughable scene. Still, we were determined to get a video record of our observations, so no procedure was considered too bizarre. After a few sessions, however, a leopard seal surfaced a few meters away to check us out. We withdrew immediately and concluded that the method was unwise. If a leopard seal became aggressive, we were in a pretty compromised position. The experiences I described earlier confirmed the wisdom of this decision. In the months preceding my next expedition to Cape Washington, I thought often about how we could do it better. The quick and easy solution was to obtain video images remotely. I returned in 1989 with a video camera placed in a custom-made housing. (This was well before the advent of GoPro cameras. I weep at the thought of what I could have done with such modern technology. Oh, well. Magellan would probably cry to think about how we travel the world now, especially since when he tried he didn’t make it back.) We mounted a connector to the top of the housing that allowed us to

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Figure 11.1. Preparing to deploy the “camera in a can” at the ice edge.

attach a two-meter-long extension arm. Along with a portable, off-theshelf video monitor, this allowed us to stand well back from the ice edge. The person watching the monitor would tell the cameraman where to point the camera to keep the subject centered. We used this system for a few seasons to obtain footage of leopard seals chasing penguins. At times, instead of hanging the camera over the ice edge, we’d cut a small hole through thin ice and lower the camera through it. On one occasion while we were recording, a seal approached the camera, pushed the housing around, and even did a test bite on it. There were also occasions when a seal would stick its head through the small hole before we put the camera in place. Still the procedure was not quite good enough for me. It was like putting a remote camera on the moon. It was better than nothing, but nowhere near as good as putting a man there. I thought about putting a diver in the water at the ice edge, but I was uncertain how the seals would respond. Based on their level of aggression when we walked the edge, I felt there was a risk of attack. However, I decided we could do it with a protective cage, and that is what we did in 1990. I arranged for the construction of an aluminum “seal exclusion cage” (SEC), much like a shark cage, and had it transported to Cape Washington. As luck would have it that season, a thin ice shelf had formed at the

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fast-ice edge a couple of kilometers southeast of the cape, and it remained for nearly a month. The emperors established first one and then three exit holes in this ice, each one progressively seaward of the 20-centimeter-thick fast-ice edge. The conditions were perfect for underwater observations. We selected a spot 10 meters from what we called dive hole 1. During the time this hole was the penguins’ only exit through the thin ice, 90% of the returning birds—about four hundred per hour—came through it to get onto the fast ice and then walk or toboggan into the colony. We used a chainsaw to cut a square hole in the ice and fit the SEC snugly into it. My only concern (and worst nightmare) was that a seal might come out of the penguin hole, scoot across the ice, and enter the SEC from the top. To eliminate that possibility, we built an ice-block wall between the penguin hole and the SEC. My concerns turned out to be unfounded, as no seal ever attempted to this. However, no sooner had we placed the SEC into its hole than we were shocked to see it come back up again. A seal was trying to shove it out of the water! We had to anchor it down so the seal couldn’t push it out. I lay down on the ice next to the SEC to look through the air–water interface and found myself nearly nose to nose with the seal on the other side of the SEC, apparently as curious about us as we were of it. I was the first to make a dive in the SEC. Nervous with anticipation, I ate three chocolate bars, one after the other, in the short time I waited to leave the dress-up tent and enter the water in my dry suit. I hoped the seal wouldn’t be too close right away so I could get my initial underwater experience without swallowing my mouthpiece. The seal did not accommodate me. Moments after I entered the frigid water, the seal approached. It circled within one to two meters of the cage for several minutes, making fast passes. Then, at one point, it came right up to me in the cage. No aggressive moves, no lunging, just curious. For several moments we both hung motionless in the water, less than a meter apart, just staring at each other. 12 Nose to nose with a leopard seal for a stare down! It was fantastic! It was sublime! I was really on a high when I came out of the water after that. After a while, the seal habituated to divers in the SEC and paid us little attention (plate 23). We, on the other hand, never got tired of their presence and were always on a marine mammal high when they were around. For our dives, we used a single-hose regulator connected by an extension hose to a compressed air tank on the ice. Usually Paul Ponganis and I each made one dive per day. Our underwater limit standing still in the cage

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in −1.6° C (29°F) water was about one hour, after which we were so chilled as to be useless for most other tasks. Standing on the floor of the cage gave us a stable platform for observing the animals, and we could rest a camera on one of the crossbars to eliminate camera shake. It was as bright under the ice as on an overcast day, and we could easily spot penguins thirty meters away in the clear water. The excellent visibility allowed us to observe and document both the tactics used by the seals to catch birds and the tactics used by the penguins to avoid being eaten. From the SEC, we could see both departing penguins diving in and returning birds approaching the exit hole. Penguins coming back to the colony would swim slowly as a tight group of ten to two hundred birds. Seeing them coming toward us out of the gloom was like watching an attack formation of Star Wars X-wing fighters. Their approach depth of 10 to 20 meters allowed them a view under the thick ice, where a leopard seal could be lurking. When the birds reached the hole, they circled below it, going every which way instead of in a single direction as flying birds do when soaring on a thermal. At some point, if no seal was spotted, a few would rocket upward to the opening and launch onto the ice. This seemed to have a facilitating effect and others would join in, until at times there were five to ten birds ascending together into the hole. Occasionally they’d collide during the ascent or during landings on the ice. As soon as the birds made their move upward, they employed their ultimate defensive tactic: contrails (plate 24). I mentioned in chapter 10 how this release of bubbles from the feather coat may serve to decrease drag when the penguin is aiming for speed. However, by virtue of their flocking behavior on arrival at the ice edge, emperors seem to have refined it to another useful purpose as well. When a large number of birds coalesces, as they do when exiting a hole or taking flight when startled, it results in a massive bubble cloud, almost like an underwater explosion. It can obscure the birds, much like the defensive ink cloud used by a squid or octopus. Because it is composed of air instead of ink, the cloud may have an obscuring effect not only on visual predators, such as the leopard seal, but also on killer whales, which use echolocation and for which the curtain of bubbles may be opaque. It was a fascinating phenomenon to watch. The contrails appeared to form at either slow or high speed, but most commonly at high speed. That they could form during slow, level swimming suggests that it is a voluntary response. From our videotapes and direct observations, it seemed that there were two sources for the bubbles. The largest were from exhaled air.

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The smaller streaks flowed mainly from the dorsal area, and less so from the side and belly feathers. If something (such as an approaching seal) startled a bird, then almost in unison the rest of the flock would stop circling and hastily retreat to open water. The resulting explosion of contrails made the vanishing birds appear as a cloud of white streaks. Occasionally, a guano burst contributed to this obscuring cloud. You could say the approaching seal had literally scared the crap out of them. Leopard seals attempting to catch a bird in the water had their work cut out for them. One of the first things we learned from our SEC observations was the birds are so maneuverable, and they accelerate so fast, that if the penguin knows a seal is there, the leopard seal doesn’t have a chance. A seal can’t accelerate or maneuver like an emperor, and I don’t think seals can swim as fast. Even if they can, it takes them a while to get up to speed, but by then the bird is long gone. Like its African namesake, the leopard seal must rely mainly on ambush. To that end, it was apparent that the seal used two underwater hiding places to wait for arriving penguins. One was behind the rubble pile, if there was one. For the penguin, this pile was both a curse and a blessing. In the dark interior landward of the edge, a seal could effectively hide from their view. Depending on the thickness of the rafted ice, the birds might have to make a high leap to clear the edge and land safely beyond the pile. The more extensive a thin edge, and the less uneven the rubble below, the better. These conditions gave the penguins a broad underwater view far enough back from the edge to prevent a seal from hiding close enough to make an effective pursuit. High-speed arrivals followed by high leaps over ice edge barriers were common. Failing to clear the ice was often fatal, though, as the penguin fell back into the waiting jaws of a leopard seal. If there was a shelf of new, thin ice, the seal would lurk below the thicker fast ice. This was somewhat disadvantageous to the seal, since it kept the predator up to 10 meters away from the penguin hole. For the penguins, whether this condition was advantageous or not depended on the thickness of the shelf. As long as it wasn’t too thin, the birds had the advantage because the seal’s hiding place was so far away. If the shelf was too thin, however, it was advantage: seal. The penguins were highly visible from below as they tobogganed across the shelf, and a submerged seal could easily track them and break through to make a catch. This probably explains the haste of the birds until they were well clear of the exit hole and onto thick ice, where they would stop and gather into a preening group for a few minutes before proceeding in a long line to the colony. Under the more common conditions of no thin ice shelf, the birds had to

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approach the thick ice edge, close to where a seal might be hiding. In these situations, the seal would make a sprint to grab a bird, even following it onto the ice if it didn’t manage to catch the penguin before it left the water. One time I was using video to measure an emperor’s speed as it began a rapid ascent. Simultaneously, a leopard seal shot toward the bird. As soon as the bird changed direction and fled, the seal gave up the chase. In contrast to the seals’ limited success in capturing arriving birds in the water, we were impressed with the ease with which a bird could be taken when a group was leaving. Each departure was accompanied by much splashing and calling. The commotion directed the seal to the birds, and the larger the departing flock, the more time for the seal to arrive before it was over. For a few seconds the penguins must have been “flying blind,” unable to see well as they entered the dark marine environment from the very bright, snow-covered sea ice. This was long enough for the seal to grab a penguin. This always amazed us. Somehow in the mêlée of the departing birds, surrounded as they were by a dense froth of bubbles, the seal selected an unfortunate victim. How it found the bird in the bubble fog, and how it avoided being jabbed in the eye by a dagger-like beak mounted on a 25-kilogram, fast-moving torpedo, is not clear. 13 A safer tactic was engaging in “hot” pursuit, which eliminated the risk of being poked in the eye. The problem for the seal was to chase down an emperor penguin that could outmaneuver it and was faster. For this to work, the bird had to be surprised at the start of the match-up. In any case, waiting in the water next to the edge and intercepting a bird that was part of a departing flock was the seal’s most successful strategy. In all, we used the SEC for two weeks in November. We dived nearly every day, until the ice became so thin that neither we nor the penguins were able to cross it safely to reach this location. We accomplished about twenty hours of underwater observation. Some of the video footage and photographs we obtained has appeared in documentaries and in various magazines, such as National Geographic. An Australian film team also spent a day with us, shooting with a specialized camera for the Imax movie Antarctica. Because of the widescreen effect, their underwater scenes captured the sense of being there better than any of our footage or others I have seen. I’ll conclude this chapter with a final few comments. I have always been aware of the value of the opportunity I had to work at Cape Washington, but I never guessed, even after my first visit in 1986, how remarkable the whole experience would be. To those who made it possible, I will be eternally grateful. As for the penguins, whose color pattern makes them impossible to distinguish one from another (with the exception of some color

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Figure 11.2. A mature female leopard seal that we saw in two consecutive seasons at Cape Washington.

morphs), we missed the experience of knowing individual birds. On the other hand, leopard seals can be differentiated. The spotting pattern on their neck is distinctive. I will never forget Star, with her perfect five-point emblem on the left side of her neck (figure 11.2). She was a big, beautiful animal that we saw during two consecutive seasons and who caught many penguins, as well as giving us a start from time to time as we walked along the Cape Washington esplanade of ice. She was one of the seals that waited on the ice at a favored penguin arrival site and caught them as they flew past. I had mixed feelings about her success, just as I would have had mixed feelings if I saw a killer whale take her, as I had seen one take a crabeater seal.

[ Ch a pter 1 2 ]

Climate, Conservation, and Consumption History tells us that exploration and exploitation of the earth and its resources have always gone hand in hand, with little care for what the consequences might be. . . . There is another option . . . places that are special, unique, and important enough to leave alone—and one of those places is the deep. Helen Sca l es, The Brilliant Abyss

I hope the preceding chapters have made clear to the reader the marvelous uniqueness of emperor penguins, as well as the uniqueness of the Ross Sea colonies. For those reasons and others, I would warrant that the Ross Sea deserves the same definition and treatment that Helen Scales suggests for the deep in the quote that headlines this chapter. Leaving it alone, however, is not as simple as, say, restricting human presence, because the consequences of human activity now have a global reach, and no place is immune to our impact. The most glaring example is the dramatic rise in atmospheric carbon dioxide (CO2) since the beginning of the Industrial Age, especially in the last few decades, and the simultaneous rise in global temperatures. This has been a hot topic ever since Charles David Keeling, a former professor at SIO, began atmospheric measurements of CO2 at a collection site atop the Mauna Loa volcano, on the island of Hawaiˋi. The evidence is overwhelmingly clear that the two observations are closely coupled. At this point, no reasonable person will deny that both are the consequence of human activity, primarily the burning of fossil fuels. It is not my goal here to debate this issue but rather to comment on how rising temperatures might affect emperor penguins. For a species that evolved at the beginning of the Pleistocene, 2.5 million years ago, the most recent climate problems mean a lot. The emperor penguin is the most ice dependent of all penguins, indeed of all vertebrate species, including even the polar bear. The emperor breeds on fast ice, lays its

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egg on fast ice, incubates and hatches the egg in the depth of winter while on fast ice, and molts on either fast or pack ice. Most of the approximately three hundred thousand penguins in the current population will never set foot on land. Therefore, any heat-induced loss of sea ice is directly related to the ultimate survival of this species. No ice, no bird! So it was particularly troubling to learn that research in McMurdo Sound was limited in 2022 by a condition that had never before occurred in the 121-year history of human activities there: thin sea ice. If it was thin there, it was probably thin everywhere in the Ross Sea. Researchers like myself hope this isn’t a harbinger of things to come. Another troubling event occurred earlier at the Halley Bay colony in the Weddell Sea, once one of the largest and most southerly of all emperor penguin colonies. It failed completely, or nearly so, to produce chicks in three consecutive breeding seasons: 2016, 2017, and 2018. Unusually strong winds caused an early break-out of fast ice during those years. The adult birds had options, of course; they are mobile and do not use a formal nest site, thus there is no attachment to a specific area. It may be an easy move for them to migrate to another area, and that is what appears to have happened. The size of the colony at nearby Dawson-Lambton, about 55 kilometers south of Halley, has increased substantially. Most likely the new residents are from Halley Bay. The potential fate of other, more northern colonies of emperor penguins is unknown. Some are located near thicker, semi-permanent shelf ice, while others are not. If the Antarctic Circumpolar Current is warming, as seems to be the case, this will affect the development of the fast ice needed by these colonies in both West and East Antarctica. The potential for early ice break-out may be high, which would devastate breeding success. However, if the fast ice along these coasts remains intact through fledging, though perhaps reduced in area, there could actually be a positive effect. The reduced distance from the breeding site to the ice edge could mean quicker access to the water and shorter foraging trips. This would increase the feeding area and shorten the over-ice travel time between foraging bouts. This exact situation is, I believe, a primary reason the Ross Sea colonies are so successful, as they have always been close to an ice edge but protected enough that early break-outs are uncommon, at least in the larger colonies. This is not the case in the smaller colonies, which is why the Cape Crozier and Beaufort Island colonies are small and the Franklin Island colony is in between. In my view, it is all about fast-ice dimensions. Because of my frequent visits to the Ross Sea colonies during the 1990s, I was often asked what changes I had seen that might be related to a warming climate. My answer was that I hadn’t seen anything in the Ross Sea like

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what is occurring on the Antarctic Peninsula. There, temperatures are rising faster than anywhere else on the planet. In the 1960s, the Marr Ice Piedmont was at the doorstep of Palmer Station, towering over the base and dominating the scene. Now it is a long walk from the station to the receding piedmont. In addition, by now most people have heard about the dramatic break-up of the Larsen A and B Ice Shelves, among others along the peninsula. More worrying is the recent discovery that the Thwaites and Pine Island Glaciers are in jeopardy of collapsing, which would have a strong effect on the fast ice and the other glaciers of West Antarctica. I did see dramatic evidence of warming on South Georgia Island a few years ago. After my first visit to Saint Andrews Bay in 1985, I didn’t return until 2016, when I served as a guide on The World, a large residential ship. What were once the nearshore Heaney and Cook Glaciers have receded so much that they are now inland glaciers, far from the beach. In addition to the physical changes in the Antarctic Peninsula region, the species composition of penguins is changing. The gentoo penguin, a species more widespread on sub-Antarctic islands, is seeing its population increase on the peninsula. At the same time, the population of Adélie penguins has declined by 85% in the midcoastal region of the peninsula. The colony of Adélie penguins on Torgersen Island, a short distance from Palmer Station, was about 8,000 pairs in the 1970s. By 2016, it had declined to 1,200 pairs. Remarkably, in the Ross Sea, Adélie penguin populations have increased substantially at the two largest colonies, Cape Crozier and Cape Adare. Both colonies now consist of hundreds of thousands of breeding pairs, about 272,000 and 338,000 respectively. There is no sign that emperor penguin populations are increasing in the Ross Sea, compared with those of Adélie penguins. However, two of the emperor colonies in the Ross Sea (Cape Washington and Coulman Island) are the largest known of all colonies, at about twenty thousand to twentyfive thousand breeding pairs each. Also, Cape Colbeck seems to be growing rapidly, from the first count of about 6,800 chicks in 1994 to 17,000 in 2012. There is also little or no sign of the Ross Ice Shelf breaking down because of warm currents eroding the bottom, as is occurring at the Thwaites Glacier grounding zone in West Antarctica. It seems that there is a tectonic seam running up the middle of the Ross Sea continental shelf. West of this tectonic boundary, the current is different from the warm flow along the Amundsen Sea in East Antarctica, preventing erosion of the Ross Ice Shelf. How long this protective condition will last is unknown. During the last glacial maximum, twenty thousand years ago, the Ross Sea did not exist. The Ross Ice Shelf extended all the way to Cape Adare, which marks the northwest corner of the Ross Sea. Where emperor pen-

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guins had colonies then is unknown, but these colonies were likely smaller than current ones, especially in the Ross Sea, because of the paucity of reliable fast ice in protected areas where chicks could be raised. Their breeding areas were probably far enough offshore that most banks were covered, and the favored prey would not have been the Antarctic silverfish, as it is for the Ross Sea birds today. Those ancient emperors would have had to forage on midwater-pelagic prey, from the surface down to about 300 meters, much like we suspect the emperors at the northern colonies around the continent currently do. As the ice shelf receded during the current warming, which began about eleven thousand years ago, emperor penguins extended their range by moving into the developing Ross Sea. The result is that populations of emperor penguins between that time and the present have grown and are probably the largest they have ever been, at least back to the last interglacial period. Does this mean emperors are relatively immune from the effects of global warming? Not necessarily. Though the Ross Sea birds seem safe for the time being, there is a limit. If warming continues to the point that all sea ice breaks up before fledging, breeding success could decline to near zero and the survival of the species could very well be imperiled. What does all this mean in terms of conservation of this species? In the near term, habitat destruction is a bigger worry. Habitat destruction is the most common factor in the extinction of species anywhere. Fortunately, and except for one glaring exception, few Antarctic habitats are being damaged at present. A certain level of protection is provided by the Antarctic Treaty and the Protocol on Environmental Protection, which apply to all areas south of the 60°S parallel. In addition, the newly created Ross Sea Marine Protected Area (figure 12.1), the largest such area in the world, encompasses all the Ross Sea emperor penguin colonies, as well as their foraging and molt areas. This is significant because the Ross Sea emperor penguins seem to be, ecologically, a separate population from the eastern and western Antarctic populations. The Ross Sea birds may seldom leave their waters, except for a few months after fledging and except for those adults that do not breed and spend part of their winter foraging in waters due north of the sea. Three of the Ross Sea emperor penguin colonies have also been designated as Antarctic Specially Protected Areas (ASPAs), which provide the most restrictive of all Antarctic protections. People who wish to enter these areas are required to obtain permission from the governing body that presides over their country’s Antarctic activities. For the request to be granted, there has to be a compelling scientific reason, which usually excludes any nonscientific activities, such as tourism.

Figure 12.1. The signatories of the treaty establishing this protected area agreed that it would be in force for thirty-five years. Zone A covers all the emperor penguin colonies of the Ross Sea, most of their molt area, and most of their foraging area. Zone B is a special research area where Antarctic toothfish may be caught for scientific purposes. Zone C is a special research area for krill. (US Department of State.)

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The three emperor colonies in the Ross Sea designated as ASPAs are Cape Crozier, Beaufort Island, and Cape Washington. Cape Crozier, designated in 1966, is the longest-known colony and one of the smallest, and it has the oldest population surveys of any emperor penguin colony, dating back to 1902. The nearby colony of Beaufort Island was also designated in 1966. It is another small colony, and the population has recently declined so much that it may become extinct in the near future. It was designated as an ASPA because of its tenuous existence. Only a small plate of fast ice on the east side of the island supports the colony, making it susceptible to any climate-driven loss of sea ice. The third and last colony to be designated as an ASPA (in 2013) is Cape Washington. It was so designated because it is one of the largest colonies and has fast ice that remains stable throughout the spring. It is because of these two factors that Cape Washington is one of the most desirable colonies for conducting studies. It is the only known colony where both the departure of the adults after feeding their chicks and the massive chick fledging can both be reliably observed close up. All the protections afforded the Ross Sea colonies, and their special locations in the high latitudes of the far south, provide better possibilities for their survival than any other emperor penguin colonies on the continent. Unlike the substantial changes observed on the peninsula, I have seen very little change in the coastal areas of the Ross Sea, even though I have flown over most of the coastline many times and camped at several places, including Cape Crozier, Cape Washington, Coulman Island, and Cape Roget. Nonetheless, continued atmospheric loading of CO2 and the resultant warming could potentially cause a loss of sea ice in the Ross Sea, with devastating consequences. The solution to this threat is to dramatically reduce our burning of fossil fuels, but executing this solution is complicated. As home of the greatest per capita consumers in the world, the United States could lead the way, but it appears unlikely that will happen. Depressingly few political leaders have addressed the importance of concerted action to deal with consumption and population growth. In fact, in this era where many advocate politically correct solutions, such as reducing our carbon footprint, the US in 2019 nonetheless became the world’s largest producer of oil and a net oil and gas exporter. It’s an “achievement” highly touted by politicians, both then and now. Perhaps the good news, at least, is that the production of coal—the burning of which is a major CO2 producer—reached a historic low in 2020. However, coal has been replaced by oil and gas, which are only marginally better. Even the rush to develop electric cars seems to be shortsighted, an ex-

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ample of rushing to develop a product without clearly defining the necessary resources. The need for rare metals, such as manganese, nickel, cobalt, and lithium, exceeds the resources currently found on land, and developers are now looking to the deep sea. What would be the short- and long-term impacts of mining there? To go beyond the Helen Scales quote that begins this chapter, the potential consequences of this activity have not only not been considered carefully enough, they haven’t even been fully identified. Nonetheless, large companies are ready to begin, and exploration permits are being awarded. Remember the glaring exception I mentioned earlier regarding Antarctic habitats? Number two on the International Union for Conservation of Nature’s list of factors responsible for species extinction is overexploitation of fisheries. Currently, several countries are fishing for krill (a small, shrimplike crustacean) in the waters near the Antarctic Peninsula. Used as food for fish farming, as fertilizer, and as a source of omega-3 fatty acids for humans, krill has been harvested for decades, and the scale of the fishery has increased in the past few years. Some factory ships can process a million kilograms of krill per day. This is a concern because so many other species—including baleen whales, fur seals, and penguins—depend on it as a primary component of their diet. A significant reduction in the abundance of this keystone species could have serious repercussions. Unfortunately, the fishery is concentrated near to or in the middle of favored feeding grounds for baleen whales and Antarctic Peninsula penguins. A recent paper estimates that krill consumption by whales is three times that of previous estimates, and that in pre-whaling days whales consumed upwards of 430 million tons, or about the total current Antarctic biomass of krill. As rich as Antarctic waters seem to be now, the imagination runs wild thinking about what they must have been like in pre-whaling days. The krill fishery may or may not have a direct effect on emperor penguins, but there is another fishery that could: Chilean sea bass. Popularly marketed as such, it is not a bass at all, but rather two distinct species of toothfish: the Patagonian toothfish (Dissostichus eleginoides), which is found in the Southern Ocean, and the Antarctic toothfish (Dissostichus

Keystone Species A keystone species is one that is critical to the functioning of an ecosystem and to the survival of the other species in that ecosystem. If this species were to be removed or its population severely reduced, a chain of events would be set off that would dramatically change the ecosystem or even cause it to collapse completely.

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mawsoni), which lives farther south, in Antarctic waters, including in the Ross Sea. Both are deepwater fish, and both are actively fished. Of the four populations of killer whales in Antarctica, one subsists almost exclusively on fish and squid, and one of its favorite prey species is the large, oil-rich toothfish. The whales show up in the Ross Sea as the fast ice is breaking up in summer, which gives them access to the toothfish sequestering themselves under the ice. Unfortunately, this is the same time the emperor chicks are fledging. Should the fishery deplete the whales’ preferred food source, they could potentially switch prey and begin targeting emperors. For the whales, going after the chicks when they first enter the water would be like picking blueberries off a bush. Since these whales travel in large pods of up to a hundred animals, a single pod could make a serious dent in any year’s fledging cohort, if not completely wipe it out. Several years of this and the population of Ross Sea emperors could be decimated. What long-term effect this would have on Ross Sea ecology is unknown, but it would likely be substantial. Such a trophic cascade effect is entirely possible, and there is a precedent. When northern Pacific salmon and pollack populations were decimated by overfishing, it caused seal and sea lion populations to plummet. The killer whales that preyed on them turned to eating sea otters, causing a dramatic drop in otter population. This allowed the population of sea urchins to explode, and since urchins graze on kelp, the kelp forest ecosystem along Alaska’s Aleutian archipelago is collapsing, which is affecting many other species. Where this cascade of impacts finally ends is unknown. Unfettered growth seems to be the goal of industry everywhere, and it is touted in nearly every politician’s campaign, but it is not sustainable. As David Attenborough has said, “Anyone who believes in indefinite growth on a physically finite planet is either mad, or an economist.” The fact is, we are consuming the world, whether by overfishing, by razing forests and replacing them with grazing pastures and farmland, or by extractive industries that devastate the environment. What can be done about it?

Trophic Cascade A trophic cascade is a cause-and-effect series of changes in an ecosystem that is caused by a significant change in the population or occurrence of a species in that ecosystem, often a keystone species. The loss of a species, an increase in a species, or the introduction of a new species can set off a chain of events that results in a dramatically altered ecosystem. This could include the loss of several species.

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All our seemingly urgent needs could be reined in considerably by the novel idea of living more simply. In wealthy countries such as the US, where the largest numbers of big consumers reside, consumption could be reduced with little hardship. We could eat less meat, for example. (For those who are old enough to remember, during World War II there was “meatless Tuesday.”) Instead of the “throwaway” mentality of our industries, we could build things that last and are easily repaired if they break. We could stop making single-use items that end up polluting the environment. We could invest in energy efficiency instead of burning more fuel. We could move manufacturing back from overseas, thereby creating local jobs and reducing the pollution caused by shipping. This would also reduce the probability of supply disruptions, such as when a huge container ship recently blocked the Suez Canal. The result of people consuming less and living more simply, both at home and abroad, would be less competition between people and nations, less squabbling over land and resources. and less environmental destruction. It would also be the quickest way to achieve sustainable economies in the US and worldwide. It could even mean restoration of areas that have been damaged, and the resurgence of wildlife that has been pushed to the brink of extinction. 14 We need to recognize that true wealth on this planet is not represented by money or material goods but by something we all share: the incredible beauty and diversity of life.

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Acknowledgments

In such an endeavor as this book about following emperor penguins across the Ross Sea for more than twenty years, and then letting the results age for nearly another twenty years, the memory of many players tends to fade. I owe much to many, but to keep this section to a reasonable length I will mention only some special notables. (Remarkably, I am still in touch with most of them.) First and foremost is Polly Penhale, who was the program manager at the National Science Foundation’s Office of Polar Programs during the time of my journeys from 1985 to 2005, when I was usually in charge of the field camp at Cape Washington. Between field-camp episodes were a few extra forays, including several aboard a US Air Force KC-10 refueler high above the Ross Sea, in 1993 and 1994, and two aboard the RVIB Nathaniel B. Palmer as it cut through sea ice to the most southern and eastern borders of the Ross Sea. My emperor penguin program began with a special “creative scientist” grant from the National Science Foundation, and it was continued with more routine NSF funding to complete the project. Without Penhale’s encouragement and support, the study would not have proceeded the way it did. The final wrap-up of my Cape Washington effort was enhanced by Paul Ponganis. In 2005 he included me on his own project in order to complete our work on population surveys of the emperor penguin colonies of the Ross Sea and finalize the diving program of emperor penguins at Cape Washington. Few scientists have had the good fortune that I have had in forming such a partnership as I have with Paul. He was on almost every expedition with me after he joined my group in 1987. We both benefited from the mathematical skills of his wife, Kathi, who participated in many of the data analyses we conducted. Other team members and I were also relieved to know that we had a first-class medical doctor on hand in case of an injury. Fortunately, no injuries ever occurred.

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Over the Cape Washington years, there were many who worked with me in the field. The list is long and includes Don Croll, Scott Eckert, Markus Horning, Carsten Kooyman, Steve Smith, and Sheridan Stone. (It is with sadness I learned that Sheridan recently died.) In later years, besides Paul Ponganis, there were Geoff Gearheart, Kim Goetz, Tory Kooyman, Gitte McDonald, Greg Marshall, and Phil Thorson. Added to this team of investigators were a few foreign scientists, such as Yves Cherel, Patrice Robison, and Robert Van Dam. Andre Ancel and Graham Robertson participated in my projects at other colonies near Cape Washington. All were extremely capable and wonderfully pleasant to be with in the field. It was a golden era for me. It was my polar Camelot, and I hope the same could be said by all the team members. Conducting field projects at the cape was complex and involved helpful personnel from the general contractors assigned to Antarctic operations, such as Holmes and Narver, ITT Antarctic Services, Antarctic Support Services, Raytheon Polar Services, and Lockheed Martin, to mention a few. Overseeing these organizations and providing me with valuable help and advice was David Bresnahan, who was the NSF representative at McMurdo Station during most of my years working at the station and in the field camps. He was very much a “can-do” person, and it was through discussions with him that the air support for reaching the cape evolved, as well as the never-before-tried situation of having a scientist on the KC-10 winter flights to McMurdo Station. Another key person during my short stays at McMurdo Station was Crary Lab manager Kristin Larson. Kristin arranged suitable labs for me and my teams so we could set up and test equipment before we launched into the field. Enormously helpful, her assistance always came with a smile. She even went to the trouble of taking aerial photographs of Coulman Island for me on her winter flight to McMurdo Station. These were the only images obtained at this time of year and valuable in our assessment of the colony later in the spring. She even went so far as to go with us on our putin at Coulman Island. What was supposed to be a short stopover for her turned into three days, because of help we needed with misplaced equipment. There was an accidental bonus to that extra effort. As far as I know, Kristin is the first and only woman to overnight at Coulman Island. I was proud to have her with me and share the incredible beauty and dynamics of “Thunder Island.” And finally, I am grateful to Martin Jeffries for generously including me on his winter cruise to the Ross Sea, which allowed me to see the conditions in the Cape Washington colony at that time of year. I am also grateful

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to John Bengtson for generously including me on his summer cruise to the eastern Ross Sea, without which much of the information I have on the molting and post-molt journeys would not exist. To all these folks I will always be grateful.

Annotated Bibliography

Pr eface Cherry-Garrard, A. The Worst Journey in the World, Antarctic 1910–1913. 1st ed. London: Constable, 1922. A first edition is difficult to find. Other editions are available, including a paperback single volume. It is said that George Bernard Shaw coached Cherry-Garrard and suggested the title after reading about the winter journey to Cape Crozier. He spins a good story, and it is an important read for anyone going to or interested in the Antarctic. For anyone going to see or study emperor penguins, it is required reading, especially the chapter on the winter journey. Isenmann, P. P., E. P. Jouventin, J. Prévost, and M. V. Beveren. “Note sur le contrôle de quelques espèces d’oiseaux bagués en Terre Adélie de 1968 à 1970.” L’Oiseau et R.F.O. 41 (1971): 1–7. Written in French and difficult to access. Prévost, J. Ecologie du manchot empereur, Aptenodytes forsteri. Paris: Hermann, 1961. Difficult to access and written in French. It is the first comprehensive report on the courting and breeding behavior of the species and the basis for a continuous and longest-term study of the species. Prévost had the easiest access to an emperor penguin colony from a permanent overwinter station. Prévost, J., and V. Vilter. “Histologie de la sécrétion oesophagienne du manchot empereur.” Proceedings of the XIII International Ornithological Congress (1963): 1085–94. This is the first report that the males could feed the chick from an esophageal secretion if the female did not arrive by the time of hatching. Stonehouse, B. The Emperor Penguin (Aptenodytes forsteri, Gray): I. Breeding Behaviour and Development. Falkland Islands Dependencies Survey Scientific Reports 6. London: Her Majesty’s Stationery Office, 1953. Good luck finding this report in any but the most comprehensive libraries. The first report on the breeding behavior of the emperor penguin.

Ch a pter 1 Kooyman, G. L. “An Analysis of Some Behavioral and Physiological Characteristics Related to Diving in the Weddell Seal.” Antarctic Biology ser. 11 (1968): 227–61. The first technical report on the detailed diving characteristics of a diving animal.

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———. “Maximum Diving Capacities of the Weddell Seal (Leptonychotes weddelli).” Science 151 (1966):1553–54. One of the early reports on the diving duration and depth of an aquatic, airbreathing animal. ———. “Techniques Used in Measuring Diving Capacities of Weddell Seals.” Polar Rec. 12 (1965):391–94. Well-illustrated, short note on the first method for direct measurements of the underwater behavior of a diving animal. ———. Weddell Seal: Consummate Diver. Cambridge: Cambridge University Press, 1981. A popularized account of the life of what has become perhaps the most studied aquatic, air-breathing vertebrate. Since this was published, studies on Weddell seals have been nearly continuous, with many authors and students conducting them.

Ch a pter 2 Kooyman, G. L., Y. Cherel, Y. Le Maho, J. P. Croxall, P. H. Thorson, and V. Ridoux. “Diving Behavior and Energetics during Foraging Cycles in King Penguins.” Ecological Monographs 62 (1992): 143–63. Kooyman, G. L., R. W. Davis, J. P. Croxall, and D. P. Costa. “Diving Depths and Energy Requirements of King Penguins.” Science 217 (1982): 726–27. The first diving records of three birds during their whole foraging cycle for nurturing chicks. Kooyman, G. L., C. M. Drabek, R. Elsner, and W. B. Campbell. “Diving Behavior of the Emperor Penguin, Aptenodytes forsteri.” Auk 88 (1972):775–95. The first diving record of an emperor penguin, determined at Cape Crozier (as described in chapter 4). Stonehouse, B. 1956. “King Penguin of South Georgia.” Nature 178:1424–426. ———. “The King Penguin Aptenodytes patagonicus of South Georgia I. Breeding Behaviour and Development.” Scientific Report of the Falkland Islands Dependency Survey 23:1–81. In this not easy-to-get monograph, Stonehouse is first to describe the unusual annual cycle of king penguins, in which it takes about fourteen months for the adults to fledge the chick. It includes the description of the chicks and their fasting for much of the winter while the adults are away.

Ch a pter 3 Kooyman, G. L. “Breeding Habitats of Emperor Penguins in the Western Ross Sea.” Antarctic Science 5 (1993): 143–48. In this report, six of the seven Ross Sea colonies are described in detail. Each colony has unusual conditions, which suggests the penguins’ preferences to certain habitats. Kooyman, G. L., D. G. Ainley, G. Ballard, and P. J. Ponganis. 2007. “Effects of Giant Icebergs on Two Emperor Penguin Colonies in the Ross Sea, Antarctica.” Antarctic Science 19, no. 1 (2007): 31–38. The most devastating effects were caused by the giant iceberg B15A colliding with the Ross Ice Shelf, sea ice, and Cape Crozier near the colony. For the year 2001,

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the colony was destroyed, all chicks were lost, and the number of adult breeding birds that died were estimated. No such total killing event had been recorded before in the Ross Sea, but Beaufort Island was a close second, with many chicks dying during the time of the event, which included blockage of the adults’ route to feeding grounds. The extensive sea ice interfered with adult travel for effective foraging. Kooyman, G. L., and P. J. Ponganis. “The Rise and Fall of Ross Sea Emperor Penguin Colony Populations: 2000 to 2012.” Antarctic Science 29 (2017):201–8. This report contains the most recent population estimates for all emperor penguin colonies in the Ross Sea, including the first reliable counts at Cape Colbeck. It also exceeds the accuracy of all satellite censuses taken over the last few years, and it includes estimates for both adults and chicks. For these geographically associated colonies, no trend was apparent in the annual surveys for the twelve years from 2000 to 2012. The variability noted may be attributable to different atmospheric and sea-ice conditions from year to year.

Ch a pter 4 Campbell, D. G. The Crystal Desert: Summers in Antarctica. New York: Houghton Mifflin, 1992. This book won the publisher’s literary fellowship award for excellence and is worth reading for a fuller understanding of the Antarctic Peninsula’s history, biology, and current human activities. Lambert, K. The Longest Winter: The Incredible Survival of Captain Scott’s Lost Party. Washington, DC: Smithsonian, 2004. This is an easy-to-access, popularized account of one of the most remarkable survival stories of all time. A good read by a skilled writer, Katherine Lambert. At the beginning is an excellent map of the Ross Sea (though Cape Washington does not appear on the map). At the end of the book, the author includes an informative gazetteer about various landmarks around the Ross Sea. Alas, again there is no reference to Cape Washington. Clearly it was not important to her, but is very much so to emperor penguins and to me. The final pages in the book are notes to various parts of the book, conversations that took place, and definitions of some terms. This is exceptional information, because such notes seldom appear in books on exploration. Levick, G. M. Antarctic Penguins: A Study of Their Social Habits. London: William Heinemann, 1914. As part of Scott’s last expedition, the northern party explored from Cape Adare in the north to Ross Island in the south. While at the Cape Adare Adélie penguin colony, Murray Levick, the medical officer of the group, studied and later published the first account of penguin breeding habits.

Ch a pter 5 Le Maho, Y. “How Penguins Store Food: The Discovery of an Antimicrobial Molecule.” In Penguins; The Ultimate Guide, edited by T. de Roy, M. Jones, and J. E. Cornthwaite, 160–61. Princeton, NJ: Princeton University Press, 2014. An exceptionally comprehensive book. Of particular interest to us was the article on the newly discovered molecule spheniscin, which suppresses digestion for

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weeks in the king penguin male incubating the egg, thus enabling him to feed the newly hatched chick.

Ch a pter 6 Kooyman, G. L., K. Goetz, C. L. Williams, P. J. Ponganis, K. Sato, S. Eckert, M. Horning, P. T. Thorson, and R. P. Van Dam. “Crary Bank: A Deep Foraging Habitat for Emperor Penguins in the Western Ross Sea.” Polar Biology 43 (2020): 801–11. This recent paper shows that emperor penguins, over the span of a ten-year study, made frequent deep dives to Crary Bank. The conclusion was that emperor penguins rely on what may be an important source of Antarctic silverfish, their favorite prey. A record deep dive for the Ross Sea was 552 meters. Kooyman, G. L., and T. G. Kooyman. “Diving Behavior of Emperor Penguins Nurturing Chicks at Coulman Island, Antarctica.” Condor 97 (1995): 536–49. Similar deep-diving results were reported in this study of emperor penguins at the Coulman Island colony. Ponganis, P. J., R. P. Van Dam, G. Marshall, T. Knower, and D. Levenson. “Sub-ice Foraging Behavior of Emperor Penguins.” Journal of Experimental Biology 203 (2000): 3275–78. In this study of emperor penguins diving from an isolated hole, a submersible video camera was attached to birds for the first time. Videotape showed a bird capturing fish hiding in the under-ice platelet layer. Robertson, G. G. The Foraging Ecology of Emperor Penguins (Aptenodytes forsteri) at Two Mawson Coast Colonies, Antarctica. Report 138. Hobart: Antarctic Division, Department of the Environment, Sport, and Territories, 1995. This special report, which may be difficult to find in US libraries, is the author’s PhD thesis work. Data were collected from emperor penguin colonies at Auster and Taylor Glacier. The latter is one of the few land-based colonies. Interesting comparisons are made with the Ross Sea colonies. In general, the birds’ dives were shallower than dives made by birds from the Ross Sea colonies. Rodary, D., W. Bonneau, Y. Le Maho, and C. A. Bost. “Benthic Diving in Male Emperor Penguins Aptenodytes forsteri Foraging in Winter.” Marine Ecology Progress Series 207 (2000.): 171–81. The conclusions in this paper confirm everything I note in this chapter and in my 2020 paper. The exceptional difference is that the benthic hunting of these penguins was so shallow, 200 to 300 meters, compared to our study at Cape Washington, where hunting on the Crary Bank was 400 to 500-plus meters. Wienecke, B. C., and G. Robertson. “Foraging Space of Emperor Penguins, Aptenodytes forsteri, in Antarctic Shelf Waters in Winter.” Marine Ecology Progress Series 159 (1997):249–63. Wienecke, B., G. Robertson, R. Kirkwood, and K. Lawton. “Extreme Dives by FreeRanging Emperor Penguins.” Polar Biology 30 (2007): 133–42. This is an interesting summary report on diving for all the known studies conducted at that time. Among the dive reports is the deepest dive made by an emperor penguin. In 1994, a bird reached a maximum depth of 564 meters, and this has never been exceeded. Zimmer, I., R. P. Wilson, C. Gilbert, M. Beaulieu, A. Ancel, and J. Plötz. “Foraging

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Movements of Emperor Penguins at Pointe Géologie, Antarctica.” Polar Biology 31 (2008): 229–43. Similar to the paper above by Rodary and colleagues, with a high-speed sample rate of every two seconds so they could determine fast movements that might indicate catching prey. They incorporated the terms catch per unit effort (CPUE) and area-restricted-search index (ARSi) to interpret some of their data. Since we did not sample at such a high rate, wanting to not fill the memory of the TDRs before the trip ended, we never engaged in that interpretation.

Ch a pter 7 Kooyman G. L., T. G. Kooyman, M. Horning, and C. A. Kooyman. “Penguin Dispersal after Fledging.” Nature 383 (1996): 397. This paper describes the first experiment to solve the mystery of where all the chicks of the Ross Sea went after leaving the colonies. Even though there are tens of thousands of fledglings that leave the colonies between mid to late December, none are seen at sea. They had left the Ross Sea. Kooyman, G. L., and P. J. Ponganis. “The Initial Journey of Juvenile Emperor Penguins.” Aquatic Conservation-Marine and Freshwater Ecosystems 17 (2007): S37–S43. Labrousse, S., A. R. Solow, F. Orgeret, C. Barbraud, C. A. Bost, J.-B. Sallée, H. Weimerskirch, and S. Jenouvrier. “First Odyssey beneath the Sea Ice of Juvenile Emperor Penguins in East Antarctica.” Marine Ecology Progress Series 609 (2019): 1–16. Even from the distant colonies and lower latitudes of East Antarctica, the juveniles travel north to the Southern Ocean until winter, when they return to the pack ice. Wienecke, B., B. Raymond, and G. Robertson. “Maiden Journey of Fledgling Emperor Penguins from the Mawson Coast, East Antarctica.” Marine Ecology Progress Series 410 (2010): 269–82.

Ch a pter 8 Groscolas, R. 1978. “Study of Molt Fasting Followed by an Experimental Forced Fasting in the Emperor Penguin Aptenodytes forsteri: Relationship between Feather Growth, Body Weight Loss, Body Temperature and Plasma Fuel Levels.” Comparative Biochemistry and Physiology 61A (1978): 287–95. This is one of the few studies of fasting in this species and not an easy report for the general reader to get. Emperors fast twice during the annual cycle. The most famous one is when the male fasts for 120 days while mating and incubating the egg. The female also fasts during this time, for about sixty days. Then there is the molt, when both male and female fast for thirty-five days. Kooyman, G. L., E. C. Hunke, S. F. Ackley, R. P. van Dam, and G. Robertson. “Moult of the Emperor Penguin: Travel, Location, and Habitat Selection.” Marine Ecology Progress Series 204 (2000): 269–77. This is the first study of where emperor penguin adults disappear to during the early summer. Shackleton, E. South: The Story of Shackleton’s Last Expedition, 1914–1917. London: William Heinemann, 1919.

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This is an exceptional account of survival in the Antarctic after losing their ship. Told by the leader of the expedition, and recounted numerous times by other authors. Wienecke, B., R. Kirkwood, and G. Robertson. “Pre-moult Foraging Trips and Moult Locations of Emperor Penguins at the Mawson Coast.” Polar Biology 27, no. 2 ( January 2004): 83–91.

Ch a pter 9 Gearheart, G., G. L. Kooyman, K. T. Goetz, and B. I. McDonald. “Migration Front of Post-moult Emperor Penguins.” Polar Biology 37 (2014): 435–39. Goetz, K. T., G. L. Kooyman, and B. I. McDonald. “Habitat Preference and Dive Behavior of Non-breeding Emperor Penguins in the Eastern Ross Sea, Antarctica.” Marine Ecology Progress Series 593 (2018): 155–71. This is the first study of the overwintering travels of nonbreeding birds. It will probably be the last such study because of the difficulty of access, and of finding nonbreeding birds after the molt. Jouventin, Pierre. “Comportement et structure sociale chez le manchot empereur.” La Terre et la Vie 25 (1971): 510–86. This is one of the few reports on breeding behavior of emperor penguins, and it was accomplished because of easy access to the colony. However, there are several documentaries on the subject, most of them from this colony. Kirkwood, R. Emperor Penguin (Aptenodytes forsteri) Foraging Ecology. Edited by Environment Department of and Australian Antarctic Division Heritage. Kingston, Tasmania. 2001. Kirkwood, R., and G. Robertson. “The Foraging Ecology of Female Emperor Penguins in Winter.” Ecological Monographs 67 (1997): 155–76. This is the first and only study of the female’s activities after she lays the egg and leaves the colony. It’s a very important study, with low probability that it will be accomplished again at different colonies because of the difficulty of access. In fact, this study was a remarkable achievement because of what they had to do in order to accomplish the mission. ———. “Seasonal Change in the Foraging Ecology of Emperor Penguins on the Mawson Coast, Antarctica.” Marine Ecology Progress Series 156 (1997): 205–23. Kooyman, G. L., D. B. Siniff, I. Stirling, and J. L. Bengtson. “Moult Habitat, Pre- and Post-moult Diet and Post-moult Travel of Ross Sea Emperor Penguins.” Marine Ecology Progress Series 267 (2004): 281–90. Like many emperor penguin studies, this is a most improbable study because of nearly impossible access to the birds during this part of their cycle. Putz, K. “The Post-moult Diet of Emperor Penguins (Aptenodytes forsteri) in the Eastern Weddell Sea, Antarctica.” Polar Biology 15 (1995):457–63. This remarkable study was accomplished because of the stable sea ice of Drescher Inlet, a small inlet in one of the less-remote areas of the Weddell Sea. Not stated was how they got there, but most likely by icebreaker. Such opportunities are diminishing with the warming trends occurring in the Antarctic and the reliance on stable sea ice. Van Dam, Robert P., and Gerald L. Kooyman. “Latitudinal Distribution of Penguins,

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Seals and Whales Observed During a Late Autumn Transect through the Ross Sea.” Antarctic Science 16 (2004): 313–18. Winter cruises in the Antarctic are rare and usually dedicated to studies other than of top predators. This cruise was one that traveled in midwinter all the way south to the Ross Ice Shelf. Such a cruise has not been repeated since, although both the South Koreans and Chinese have very capable icebreakers that service their Ross Sea stations in the summer. Perhaps, a winter study might happen someday.

Ch a pter 10 Davis R. W. Marine Mammals: Adaptations for an Aquatic Life. Switzerland: Springer Nature, 2019. Jouventin, P., P. M. Nolan, J. Ornborg, and F. S. Dobson. “Ultraviolet Beak Spots in King and Emperor Penguins.” Condor 107, no. 1 (2005): 144–50. This paper shows how limited the information is on color sensitivity and the importance of adult beak and facial feather coloration. Kooyman, G. L., and Ponganis, P. J. “The Physiological Basis of Diving to Depth: Birds and Mammals.” Annual Review of Physiology 60 (1998):19–32. Meir, Jessica U., and Paul J. Ponganis. “High-Affinity Hemoglobin and Blood Oxygen Saturation in Diving Emperor Penguins.” Journal of Experimental Biology 212 (2009): 3330–38. Nicolaus, M., C. Le Bohec, P. M. Nolan, M. Gauthier-Clerc, Y. Le Maho, J. Komdeur, and P. Jouventin. “Ornamental Colors Reveal Age in the King Penguin.” Polar Biology 31, no. 1 (2007): 53–61. Ponganis, P. J. Diving Physiology of Marine Mammals and Seabirds. Cambridge: Cambridge University Press, 2015. This excellent resource has almost every detail about the subject of diving physiology and diving characteristics that the casual or serious reader would want to know, and what species have been studied. Ponganis, P. J., T. K. Stockard, J. U. Meir, C. L. Williams, K. V. Ponganis, and R. Howard. “O2 Store Management in Diving Emperor Penguins.” Journal of Experimental Biology 212 (2009): 217–24. Quick, N J., J. M. Shearer, W. R. Cioffi, A. Fahlman, and A. J. Read. “Extreme Diving in Mammals: First Estimates of Behavioural Aerobic Dive Limits in Cuvier’s Beaked Whales.” Journal of Experimental Biology 225 (2020): 1–6. This paper discusses one of the great diving species, with details about some of the physiological characteristics. Sato, K., K. Shiomi, G. Marshall, G. L. Kooyman, and P. J. Ponganis. “Stroke Rates and Diving Air Volumes of Emperor Penguins: Implications for Dive Performance.” Journal of Experimental Biology 214 (2011): 2854–63. In addition to some of the performance characteristics of the species, the authors recorded the longest verifiable dive duration of 27.6 minutes; also reported is the recovery behavior after such a long dive. This observation suggests that the dive was an accident, or a successful escape from a predator. The first report on the foraging behavior of emperor penguins from Cape Washington. Tyack, P. L., M. Johnson, N. A. Soto, A. Sturlese, and P. T. Madsen. “Extreme Diving of Beaked Whales.” Journal of Experimental Biology 209 (2006): 4238–53.

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This is one of the earliest reports on the incredible capabilities of beaked whales. Williams, C. L., J. C. Hagelin, and G. L. Kooyman. “Hidden Keys to Survival: The Type, Density, Pattern and Functional Role of Emperor Penguin Body Feathers.” Proceedings of the Royal Society B 282 (2015): 20152033 (8pp). To my knowledge, this is the only report on the details of the feather coat in penguins, and perhaps any diving bird. If you want to know the details of all emperor penguin feathers, this is the paper to read. It shows the entire diversity of the twenty-two different feathers and the density of the contour and plumulaceous feathers. Williams, C. L, J. U. Meir, and P. J. Ponganis. “What Triggers the Aerobic Dive Limit? Patterns of Muscle Oxygen Depletion during Dives of Emperor Penguins.” Journal of Experimental Biology 214 (2011): 1082–12. Like the Ponganis book cited above, this article also presents an excellent discussion of the aerobic dive limit. Williams, C. L., K. Sato, K. Shiomi, and P. J. Ponganis. “Muscle Energy Stores and Stroke Rates of Emperor Penguins: Implications for Muscle Metabolism and Dive Performance.” Physiological and Biochemical Zoology 85, no. 2 (2012): 120–33. This is an essential paper for understanding the elements of oxygen store management in the emperor penguin.

Ch a pter 11 Ainley, D. G., G. Ballard, B. J. Karl, and K. M. Dugger. “Leopard Seal Predation Rates at Penguin Colonies of Different Size.” Antarctic Science 17: 335–340. Kooyman, G. L. “Leopard Seals of Cape Crozier.” 1965. Animals 6, no. 3 (2005): 58–63. Krause, D. J., M. E. Goebel, and C. M. Kurle. “Leopard Seal Diets in a Rapidly Warming Polar Region Vary by Year, Season, Sex, and Body Size.” BMC Ecology 20 (2020): 32–48. None of these papers were of predation on emperor penguins, which shows the limited number of observed predations on emperor penguins, as reported in this chapter.

Ch a pter 1 2 Climate Broecker, W. S., and G. H. Denton. “What Drives Glacial Cycles?.” Scientific American 262 (1990): 49–56. Fretwell, P. T., and P. N. Trathan. “Emperors on Thin Ice: Three Years of Breeding Failure at Halley Bay.” Antarctic Science 31 (2019): 133–38. The good news about the nearly total loss of chicks at Halley Bay has been the evidence that many of the birds have moved a short distance to the betterprotected Dawson-Lambton area, 55 kilometers away. This demonstrates one of the exceptional attributes of emperor penguins, that they are mobile and flexible about their breeding habits. Ksepka, D. “Penguin Genomes Unveiled.” March of the Fossil Penguins (blog), September 2019. https://fossilpenguins.wordpress.com/2019/09. This blog began in October 2009 and continues to the present, with monthly posts.

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It covers mainly discoveries about fossil penguins, of which fifty species have been found, and they are still digging and counting. The post highlighted here presents a cladogram of penguin evolution and introduces a major group and project called the Penguin Genome Consortium. Go ahead and call up the website and enjoy an entertaining evening reading all about penguins, mostly ones long since dead. Larkin, A. “Mt. Everest’s Highest Glacier Is a Sentinel for Accelerating Ice Loss.” Climate and Atmospheric Science 5 (2022): 7. Montaigne, F. Fraser’s Penguin: A Journey to the Future in Antarctica. New York: Henry Holt, 2010. Fraser’s penguins are actually Adélie penguins that Bill Fraser has studied for about thirty years. There has been a large decline in the population; the main nesting area was on Torgersen Island near Palmer Station. The changing conditions are described well by Fen Montaigne, including the recession of the Marr Ice Piedmont that was once immediately behind the base and is now well back on Anvers Island. Steffen, W. “Introducing the Anthropocene: The Human Epoch.” Ambio 50 (2021): 1784–87. This article gives an extensive explanation regarding the derivation and meaning of the term. There is even a best seller with the title. It is frightening to consider that one species can have such a widespread effect on the planetary environment. Perhaps no more frightening than that one person can have a powerful effect on one nation, and if it is a large, powerful nation, too bad for us. Weart, S. R. The Discovery of Global Warming. Cambridge, MA: Harvard University Press, 2003. This book presents a very good summary of who the giants were in the field of carbon dioxide production and the greenhouse effect. The author especially mentions Roger Revelle and all his contributions to the issue of global warming. Most prominent was his hiring of David Keeling while he was director of the Scripps Institution of Oceanography. Keeling’s data resulted in a simple curve that has become the most famous of all scientific curves and ties the rising atmospheric concentration of CO2 to the rising global temperature.

Conservation Savoca, M. S., S. R. Kahane-Rapport, M. F. Czapanskiy, W. T. Gough, J. A. Fahlbusch, K. C. Bierlich, P. S. Segre, J. Di Clemente, D. N. Wiley, G. S. Penry, J. Calambokidis, D. P. Nowacek, N. D. Pyenson, D. W. Johnston, A. S. Friedlaender, E. L. Hazen, and J. A. Goldbogen. “Baleen Whale Prey Consumption Based on HighResolution Foraging Measurements.” Nature 599 (2021): 85–89. This important paper is based on sophisticated TDRs with several sensors to estimate dive effort and energetics. The prey consumption is calculated from the effort and is much higher than previously thought. The conclusion for blue whales is that they consume much more krill than previous calculations. This means the impact of their removal during peak whaling days was greater than earlier estimates, and makes it almost beyond imagination of how rich the Southern Ocean had been, in regard to krill, which is the primary prey of many species. The loss of iron fertilization by the whales also changed the ecosystem greatly.

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Consumption Ainley, D. G. “A History of the Exploitation of the Ross Sea, Antarctica.” Polar Record 46 (2010): 233–43. Estes, J. A. Serendipity: An Ecologist’s Quest to Understand Nature. Oakland: University of California Press, 2016. This is the forty-year saga of James Estes failing his draft physical and instead finding an opportunity to study the interaction of sea otters and sea urchins. From there it evolved into thousands of dives in a rather unfriendly environment for some (but not for Estes). He thrived on the challenges and discoveries and learned much about urchins and kelp forests. After years of careful work, he understood the nature of keystone species, trophic cascades, and the importance of top-down forcing. How such a study can develop into a scientific hot potato when charismatic species like sea otters and killer whales collide over concerns of conservation is a caution for everyone working with such species. This is an important read for everyone interested in these technical terms, how they are defined, and the research methods that apply. Few people have the determination to continue so long with such a difficult program of research. Gerson, J. R., A. Almeyda Zambrano, N. Szponar, B. Bergquist, C. T. Driscoll, E. Broadbent, G. Erkenswick, D. C. Evers, L. E. Fernandez, H. Hsu-Kim, G. Inga, K. N. Lansdale, M. J. Marchese, A. Martinez, C. Moore, W. K. Pan, R. Pérez Purizaca, V. Sánchez, M. Silman, C. Vega, E. A. Ury, M. Watsa, and E. S. Bernhardt. “Amazon Forests Capture High Levels of Atmospheric Mercury Pollution from Artisanal Gold Mining.” Nature Communications 13 (2022): 1–10. https://doi.org/10.1038/s41467-022-27997-3. McVeigh, K. “‘False Choice’: Is Deepsea Mining Required for an Electric Vehicle Revolution?” Guardian, September 29, 2021. https://www.theguardian.com/ environment/2021/sep/28/false-choice-is-deep-sea-mining-required-for-an -electric-vehicle-revolution. Vollrath, D. Fully Grown: Why a Stagnant Economy Is a Sign of Success. Chicago: University of Chicago Press, 2020. Right from the preface, the author points out that since the late 1800s there has been a stable US economic growth of 2%. Since 2000, the GDP per capita has been around 1%. However, there has been a level of material increase of about 20% from 2000 to 2018. Now, to me it seems that a common question asked regarding politicians in office is, “Are you better off today than before (the politician was elected)?” I was looking for a substantive answer to the famous quote by David Attenborough that anyone saying continued growth is essential must be either mad or an economist. This book was a help, and the only one I have found that deals directly with the argument that growth is an essential way of life. Dietrich Vollrath deals with the subject over seventeen chapters. For me it is a challenging read. At least there is someone trying to unravel the mystery of growth, and putting forth the notion that a stable economy is not so bad. Perhaps it is better to be less concerned with consumption and services, and to accept a more gentle philosophy of living simply.

Index

Page numbers in italics refer to figures. Adélie penguin (Pygoscelis adeliae), xvi, 2, 11, 27, 52, 89, 95, 108, 127, 138, 159 Admiralty Range, 31, 69 aerobic dive limit (ADL), 63, 133–35 Amundsen Sea, 106, 109, 110 Antarctic Circumpolar Current, 98–99, 101, 158 Antarctic fur seals, 12, 14, 17, 20, 21, 22, 92 Antarctic silverfish (Pleuragramma antarcticum), 86, 91, 93, 101, 102, 106, 108, 160 Antarctic Specially Protected Areas (ASPAs), 26, 160, 161, 162 Antarctic Treaty, 98, 160, 161 astronomical dark, 114 Auster colony, 88, 101, 108, 114 baleen whales, 163 Bartlett Inlet, 35, 116, 119 beaked whales, 102, 129, 135 Beaufort Island, 27, 28, 29, 69, 158, 162, 173 Bellingshausen, Thaddeus von, xv Bengtson, John, 107 benthic foraging, 88, 91, 94 bioluminescence, 66, 93, 115, 138 Bird Island, 17, 20, 22 Bohner, “Beez,” 67 brash ice. See sea ice: brash ice Bresnahan, Dave, 53, 67 British Antarctic Survey (BAS), xvii, 8, 10, 11, 12, 17, 20, 21, 22, 24 Browning Pass, 39, 41, 42, 43

Campbell, Walt, 48, 49 Campbell Glacier, 36, 42, 43, 44, 46, 56, 57, 66, 67, 76–77 Cape Adare, 26, 98, 159 Cape Colbeck, 33, 34, 35, 86, 96, 104, 105, 106, 116, 119, 120, 159, 173 Cape Crozier, xvi, xvii, 3, 17, 26, 27, 29, 36, 37, 48, 49, 52, 104, 105, 113, 158, 159, 162 Cape Roget, 31, 33, 104, 115, 116, 117 Cape Royds, 1, 3, 84 Castellini, Mike, 68 censusing. See emperor penguins: censusing Cherel, Yves, 64, 168 chinstrap penguins (Pygoscelis antarcticus), 11, 20, 127 civil twilight, 114, 118, 119, 138 Coast Guard, US, 28, 59, 80 colony, dynamics of: emperors, 50–51, 53, 57, 72, 77; kings, 13–15 colony, locations of: emperors, xvi, xvii, 24, 26–28, 30–37, 42, 100–101, 109, 158; kings, 7, 12–13, 20, 23, 64 color morphs, of emperors, 75, 128; of kings, 20, 128 colossal squid (Mesonychoteuthis hamiltoni), 93 contrails. See emperor penguins: contrails Coulman Island, xvii, 29–32, 104, 116, 128, 144, 159, 162, 168 crabeater seals, 3, 20, 107, 118, 156 Crary Bank, 86, 87, 115 crevasses, 19, 39, 42, 43–44, 45, 46, 57

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Croll, Don, 40, 44, 168 Crozet archipelago, 23, 64, 65, 128 Cuvier’s beaked whale (Ziphius cavirostris), 135

Franklin Island, 28, 29, 30, 158 French National Centre for Scientific Research (CNRS), 64 fur seals, 14, 17, 20, 21–22

demersal feeding, 88, 91, 94, 106 depth measurements. See time/depth recorder Drygalski Basin, 86, 87 Dumont d’Urville, xvi, 24, 25, 38, 74, 88, 114, 119

gentoo penguins (Pygoscelis papua), 127, 159 Gerlache Inlet, 56 giant Antarctic octopus (Megaleledone setebos), 93 grease ice. See sea ice: grease ice guano, 13, 28, 31, 32, 37, 51, 55, 73, 77, 108

echolocation, 135, 153 Eckert, Scott, 62, 68, 75 elephant seals, 10, 13, 14, 20, 21, 22, 23, 129, 135 emperor penguins, breeding, xviii, 114; censusing, 53, 75, 112, 116, 128, 173; contrails, 127, 150, 153; deep dives, 17, 52, 60, 74, 87, 89, 90, 100–101; diving physiology, xii, xvii, 3, 6, 7, 41, 99, 133, 153, 154; eyes, 136–37; fasting, xv, xviii, 83, 104, 105, 111, 115, 117, 121, 175; foraging, 81–83, 84, 88, 91, 94, 108, 110, 114, 119, 122, 133, 135, 158, 160, 161, 179; huddles, 8, 105, 113, 114, 115, 124; leaping, 92, 127, 145–46, 147, 154; predation on, 51, 56, 58, 93, 143–48, 154–55; prey selection, 18, 84, 86, 89, 91, 101–2, 108–9, 117, 118, 135, 160; travel records of, 87, 98, 105, 117, 118 Endurance, HMS, 109 epipelagic zone, 88 Evans, William (“Bill”), 8, 11 fast ice. See sea ice: fast ice fasting. See emperor penguins: fasting; king penguins: fasting feathers, as protection or insulation, 95, 123–28; brood pouch, xvi; definitive source on, 178; densest, 124; experiments with, 48; flight, 15; molting, 105, 109–11, 116, 118, 119; while swimming, 92, 124, 126, 127, 128 foraging. See emperor penguins: foraging; king penguins: foraging Forster, Johann Georg Adam, xv Forster, Johann Reinhold, xv

habitat destruction, 160 Halley Bay, 24, 158 Haswell Island, xvii Hell’s Gate, 41 Hercules LC-130. See LC-130 Hercules Hero, R/V, 99 histogram recorders, 17 Horning, Markus, 62, 68, 75, 76, 79–80, 81, 99 hydrophone recordings, 27, 112 hypoxemia, 123, 127, 131–33 hypoxia, 132–33 icebreakers, 26, 28, 59, 80, 84, 111, 118, 176, 177 International Union for Conservation of Nature, 163 isolated hole protocol, 61, 133 Jeffries, Martin, 111 katabatic winds, 1–2, 7, 10, 22, 26, 70 keystone species, 163, 164 killer whales, 14, 53, 55, 56, 58, 59, 75, 86, 102, 118, 145, 153, 156, 164, 180 king penguins, 13, 16; breeding, 13–14, 16; deep dives, 17, 49, 52, 64–66, 74; eggs, 16; eyes, 137; fasting, 14, 66; foraging, 16, 18, 64, 65; habits at sea, 16–18, 45, 133; interactions with seals, 22; physiology, 66; predation on, 14; prey selection, 18, 66; use of TDRs on, 6 Kooyman, Carsten, 28, 62, 64, 67, 68, 69, 71–72, 76–77, 79, 81, 95 Kooyman, Tory, 34, 36, 149

Index

krill, 84, 101, 106, 108, 117, 142, 161, 163 lactate, in penguins, 128, 131, 132, 133–34; in Weddell seals, 134–35; in whales, 135 lantern fish, 18, 66, 101, 102 LC-130 Hercules, 31, 36, 39, 67, 69–70 Le Maho, Yvon, 63, 66, 140 legal protective measures. See Antarctic Specially Protected Areas; Antarctic Treaty; Protocol on Environmental Protection; Ross Sea Region Marine Protected Area leopard seals (Hydrurga leptonyx), 14, 27, 51, 53–56, 58, 78–80, 103, 142–56; threats to humans, 54, 58, 78–80, 84, 148–49, 150 Llano, George, 8, 11, 16 Marion Dufresnes, 64 Markham Island, 42, 43, 66, 67 Marshall, Greg, 84 Mawson, Sir Douglas, xvii, 1 Mawson Station, 2, 88, 101, 114 McMurdo Sound, 1, 3, 4, 59, 61, 63, 69, 73, 84, 86, 93, 99, 100, 139, 140, 158 McMurdo Station, 3, 30, 31, 34, 36–38, 40–41, 44, 48, 61, 67, 70 mesopelagic zone, 108, 118 metabolism, aerobic, 63, 127, 129, 132; anerobic, 63, 127–28, 131, 132, 133–34; measurement of, 17–19, 129, 138 minke whales, 59, 86, 118 molting, 14, 105–6, 108, 109, 110; inherent dangers from, 105–6, 108, 111; mystery of locations, 104 Mount Abbott, 42 Mount Melbourne, 34, 44, 71 narwhal, 129 Nathaniel B. Palmer, 111, 116, 118, 122 National Science Foundation (NSF), 5, 8, 41, 44, 53, 59, 63, 66, 67, 81 nilas. See sea ice: nilas nunatak, 42 oceanic aphotic zone, 135 oxygen storage: in elephant seals, 129, 135;

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in penguins, 127, 128, 129, 131, 135; in whales, 129 pack ice. See sea ice: pack ice pancake ice. See sea ice: pancake ice Penguin Ranch, 62, 63, 120, 138 platelet ice. See sea ice: platelet ice Pointe Géologie, xvi, xvii, xviii, 88, 101, 114 Polar Star, 80 Polarstern, 84 polynya, 104, 112 Ponganis, Paul, 32, 61, 68, 84–85, 87, 133, 138, 152, 167 Possession Island, 64, 66 Prévost, Jean, xvi, xvii Priestley Glacier, 41, 42, 43, 46, 66, 67 Protocol on Environmental Protection, 160 radio transmitters, 18 rete mirable, 136, 138 Ross Ice Shelf, 26, 27, 49, 86–87, 119, 159 Ross Island, 1, 27, 28, 84 Ross Sea continental shelf, 87, 106, 108, 118, 159 Ross Sea Region Marine Protected Area, 160, 161 Royal Bay, 7 sample sizes, 17, 49, 104, 122 sastrugi, 39, 40 satellite colonies, 50–51 sea ice, 29; brash ice, 29; fast ice, 28, 29, 30, 33, 34, 35–37, 41, 48, 56, 84, 88, 89, 108–9, 119, 127, 135, 143–44, 146, 150, 152, 154, 157–58, 159–60, 162, 164; grease ice, 29, 121; nilas, 121; pack ice, 29, 30, 101, 104, 108–10, 117–18, 121, 138, 140, 158; pancake ice, 29; platelet ice, 29, 84 seal exclusion cage (SEC), 151–55; predecessors to, 150–51 seals. See individual names Shackleton, Ernest, 3, 11, 109 sinkholes, 59–60 Smith, Steve, 40, 44, 45, 54 Southeast Pacific Basin, 119

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South Georgia Island, 7, 8, 11, 17, 19, 21, 22, 64, 99, 159 Starke, Lisa, 99–100 Stone, Sheridan, 40, 44–47, 54 Stonehouse, Bernard, xvi, xvii, 16, 28 Sulzberger Bay, 34

toothfish, 56, 75, 93, 163–64 trophic cascades, 164 Twin Otter (airplane), 32, 56, 59–60, 81, 82

Taylor Glacier, 100, 108 Terra Nova, Bay, 34, 36, 41, 42, 43, 56, 59, 70, 71, 81, 96, 143 Thorson, Phil, 84, 99 time/depth recorder (TDR), 4–5, 47, 49, 50, 52, 60, 66, 72–75, 90, 96, 175; improvements in, 5, 64, 66, 73, 82; invention of, 4; placement and deployment of, 50, 52, 96, 140 tobogganing, xv, 88, 127, 144–46, 154 Todd, Frank, 8, 11, 99

Van Dam, Robert, 112

underwater observation chamber, 139–40

Weddell Sea, 109, 158 Weddell seal (Leptonychotes weddellii), 3, 4, 48, 61, 63, 73, 100, 133, 134, 135, 136 whales. See individual names Wienecke, Barbara, 88–89, 100–101, 108 Williams, Cassondra, 124, 131 World, The (ship), 159 Zucchelli, Mario, 75