The Puffin 9781472597533, 9781408108673, 9781408160558

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THE PUFFIN

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THE PUFFIN

MIKE P. HARRIS AND SARAH WANLESS Illustrations by KEITH BROCKIE

T & AD POYSER London

Published 2011 by T & AD Poyser, an imprint of Bloomsbury Publishing Plc, 49–51 Bedford Square, London, WC1B 3DP Copyright © 2011 text and figures by Mike P. Harris and Sarah Wanless Copyright © 2011 illustrations by Keith Brockie The right of Mike P. Harris and Sarah Wanless to be identified as the authors of this work has been asserted by them in accordance with the Copyright, Designs and Patents Act 1988. ISBN (print) 978-1-4081-0867-3 ISBN (e-pub) 978-1-4081-6056-5 ISBN (e-pdf ) 978-1-4081-6055-8 A CIP catalogue record for this book is available from the British Library All rights reserved. No part of this publication may be reproduced or used in any form or by any means – photographic, electronic or mechanical, including photocopying, recording, taping or information storage or retrieval systems – without permission of the publishers. This book is produced using paper that is made from wood grown in managed sustainable forests. It is natural, renewable and recyclable. The logging and manufacturing processes conform to the environmental regulations of the country of origin. Commissioning Editor: Nigel Redman Project Editor: Jim Martin Design by Julie Dando at Fluke Art Printed and bound in China by C&C Offset Printing Co Ltd 10 9 8 7 6 5 4 3 2 1

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Contents List of Figures

7

List of Tables

11

Introduction and acknowledgements

13

1.

Puffins and auks

15

2.

Studies of Puffins

22

3.

Appearance, development and moult

27

4.

Distribution and status in Britain, Ireland and France

41

5.

Distribution and status in Iceland, the Faeroe Islands, Norway, Russia, Svalbard, Greenland and the western Atlantic

58

6.

Colony attendance and incubation

70

7.

Chick rearing and breeding success

88

8.

Puffin behaviour (by Kenny Taylor)

103

9.

Food and feeding

114

10. Predators, pirates, parasites and competitors

139

11. Survival of Puffins and the Isle of May population

148

12. Puffins away from the colony

158

13. Puffins and people

166

14. Other threats to Puffins

178

15. Overview and the future

195

Appendix 1.

Measurements of Puffins throughout the range

201

Appendix 2.

Sources of counts and estimates and general background information used in Chapters 4 and 5

203

First and last dates of Puffins in Grampian, on the Isle of May and Fair Isle

206

Dates when Puffins were first seen on the sea and ashore and were last recorded ashore or carrying fish on Skokholm

208

Timing of breeding of Puffins on the Isle of May and the Farne Islands

210

Appendix 6.

Measurements of eggs of Puffins throughout the range

212

Appendix 7.

Annual peak and fledging weights, age at fledging and growth rates of Puffins on the Isle of May, 1974–2010

213

Appendix 8.

Breeding success of Puffins on the Isle of May, 1973–2010

217

Appendix 9.

Numbers of fish brought to young Puffins on the Isle of May, 1973–2010

220

Appendix 3. Appendix 4. Appendix 5.

Appendix 10. Diet by weight of young Puffins on the Isle of May, 1973–2010

223

Appendix 11. Lengths of sandeels, rockling and other Gadidae dropped by Puffins on the Isle of May, 1973–2010

226

Appendix 12. Lengths of sprat, herring and unidentified Clupeidae dropped by Puffins on the Isle of May, 1973–2010

228

Appendix 13. Annual mean weights of loads of fish, number of fish per load and frequency of feeds brought to young Puffins on the Isle of May, 1973–2010

230

Appendix 14. Scientific names of birds, mammals and amphibians mentioned in the text

232

References

233

Index

251

Colour Picture S ection

List of Figures CHAPTER 1 Figure 1.1.

The colonies where the major studies of Atlantic Puffins have been carried out and the approximate southern limit of the distribution in winter.

17

Figure 1.2.

The three puffins in the Pacific.

18

Figure 1.3.

The increase in wing length of adult Puffins with latitude of the colony in the east and west Atlantic.

19

CHAPTER 3 Figure 3.1.

The leg and foot of a Puffin.

28

Figure 3.2.

The Puffin’s transformation from summer to winter plumage.

30

Figure 3.3.

The development of the bill of the Puffin.

31

Figure 3.4.

Sexing Puffins by using bill measurements.

33

Figure 3.5.

The long-term decline in average weight of adult Puffins on the Isle of May before laying and when feeding young between 1973 and 2010.

35

CHAPTER 4 Figure 4.1.

The authors counting Puffin burrows on the Isle of May.

43

Figure 4.2.

Puffin colonies in mainland Scotland and the Hebrides.

45

Figure 4.3.

Puffin colonies in Orkney and Shetland.

49

Figure 4.4.

Puffin colonies in south-east Scotland and north-east England.

50

Figure 4.5.

Changes in the number of Puffins on the Isle of May, Craigleith and the Farne Islands between 1959 and 2009.

51

Figure 4.6.

Puffin colonies in England, Wales, Isle of Man, Channel Islands and France.

52

Figure 4.7.

Puffin colonies in Ireland.

55

Figure 4.8.

The decline of the Puffin population on the Sept-Îles, France.

56

CHAPTER 5 Figure 5.1.

Puffin colonies in Iceland.

59

Figure 5.2.

The main Puffin colonies in the Faeroe Islands.

60

Figure 5.3.

Puffin colonies in mainland Norway.

62

Figure 5.4.

Puffin colonies in Russia, Svalbard and Jan Mayen.

65

Figure 5.5.

Puffin colonies in Greenland.

66

Figure 5.6.

Puffin colonies in Canada and the United States of America.

67

7

THE PUFFIN

CHAPTER 6 Figure 6.1.

Dates when Puffins on Skokholm were first seen on the sea and ashore and last seen ashore or carrying fish.

71

Figure 6.2.

Seasonal changes in the age composition of Puffins on the Isle of May in the 1970s as indicated by the number of bill grooves.

74

Figure 6.3.

The relationship between egg size and adult weight at 15 colonies.

85

Figure 6.4.

The daily pattern of change-overs by members of pairs of Puffins incubating eggs on the Isle of May.

86

CHAPTER 7 Figure 7.1.

Variation in the pattern of growth as shown by two Puffin chicks on the Isle of May in 1992 that fledged at about the same weight.

91

Long-term changes in the mean peak and fledging weight of Puffin chicks on the Isle of May.

92

Colonies in Britain where data on the breeding of Puffins have been collected over a period of years.

93

Figure 7.4.

Long-term declines in mean fledging weights of Puffins on the Isle of May, St Kilda and Sule Skerry.

93

Figure 7.5.

The relationship between annual breeding success and mean fledging weight of Puffins on St Kilda.

97

Figure 7.6.

Long-term trends in breeding success of Puffins at five British colonies.

99

Figure 7.7.

The lengths of time a parent continued to visit the Isle of May after its young had fledged.

Figure 7.2. Figure 7.3.

102

CHAPTER 8 Figure 8.1.

Head jerking.

104

Figure 8.2.

Puffins billing.

105

Figure 8.3.

Low-profile walk.

108

Figure 8.4.

Pelican walk.

109

Figure 8.5.

Post-landing posture.

111

CHAPTER 9 Figure 9.1.

British auks carrying fish.

116

Figure 9.2.

Typical prey of Puffins on the Isle of May.

118

Figure 9.3.

Long-term changes in the percentage (by number and weight) of 0-group sandeels, older sandeels, sprats, herring and Gadidae (mainly rockling) in the diet of young Puffins on the Isle of May.

121

Figure 9.4.

The relationship between the mean lengths of 0-group sandeels brought in by Puffins on the Isle of May and caught in fishery surveys in adjacent waters on the same days.

122

Figure 9.5.

Long-term changes in the length of 0-group sandeels brought in by Puffins on the Isle of May, Fair Isle and Hermaness.

122

8

List of figures

Figure 9.6. Figure 9.7.

Figure 9.8. Figure 9.9.

Long-term changes in the characteristics of loads of fish delivered to young Puffins and the feeding frequency on the Isle of May.

124

The mean weight of loads of fish brought to young Puffins on the Isle of May in relation to the number of days after the first fish were seen at the colony.

125

The relationship between calorific value and length for sandeels and sprats brought in by Puffins on the Isle of May.

126

The diurnal pattern of feeds brought to young Puffins on the Isle of May.

129

Figure 9.10. Frequency distribution of daily feeding rates of Puffin chicks on the Isle of May.

129

Figure 9.11. Changes in the daily feeding frequency in relation to chick age.

130

Figure 9.12. The mean daily food consumption in relation to age of five young Puffins reared in captivity supplied with unlimited food.

130

Figure 9.13. Three trips that were tracked by GPS loggers made by a Puffin feeding a chick on the Isle of May.

132

Figure 9.14. Ten minutes output from a time-depth recorder deployed on a Puffin on the Isle of May.

134

Figure 9.15. The depths of dives recorded by time-depth recorders deployed on four Puffins from the Isle of May feeding chicks.

134

Figure 9.16. The diurnal pattern of diving for four adult Puffins from the Isle of May in July when they were feeding chicks and September after they had left the colony.

135

CHAPTER 10 Figure 10.1. The decline in the percentage of loads of fish brought to Puffin chicks on the Isle of May that were lost to gulls.

145

CHAPTER 11 Figure 11.1. The survival of adult Puffins on the Isle of May.

149

Figure 11.2. The relationship between adult survival to the following year and breeding success of Puffins on the Isle of May.

150

Figure 11.3. Month of recovery of adult Puffins ringed in north-east Britain and elsewhere in Britain and Ireland.

151

Figure 11.4. Annual survival rates of adult Puffins on the Isle of May in relation to age.

151

Figure 11.5. A model of the Puffin population on the Isle of May.

155

Figure 11.6. Colonies where young Puffins colour-ringed on the Isle of May were seen when four or more years old by which time they should have decided where to breed.

156

CHAPTER 12 Figure 12.1. Locations where Puffins ringed in north-east Britain were recovered during September to March when at least three years old.

159

9

THE PUFFIN

Figure 12.2. Kernel density distribution of the approximately daily positions of 13 adult Puffins from the Isle of May tracked by geolocators during August–December 2007.

160

Figure 12.3. Positions of a Puffin from the Isle of May tracked using a geolocator over the 2009/10 winter.

161

Figure 12.4. Locations where Puffins ringed in Orkney and Shetland and in west Britain and Ireland were recovered during September to March when at least three years old.

162

Figure 12.5. Densities of Puffins recorded during surveys at sea during (a) May to July and (b) September to February.

164

CHAPTER 13 Figure 13.1. Annual totals of Puffins fleyged on Nólsoy, Faeroes Islands between 1996 and 2010.

169

Figure 13.2. The increase in the annual total of day visitors to the Isle of May between 1975 and 2010.

174

Figure 13.3. The increase in Puffins on Eastern Egg Rock and Matinicus Seal Island, Gulf of Maine following the introduction of young.

176

CHAPTER 14 Figure 14.1. Tree mallow and Puffins on Craigleith.

181

Figure 14.2. The increase in mercury concentrations (ppm) in body feathers of Puffins from the south-west and west of Britain and Ireland.

187

Figure 14.3. The concentrations of PCB (ppm wet weight) in the fat of Puffins at various intervals after being exposed to the chemical.

188

Figure 14.4. Reported catches of sandeels from the two ICES rectangles enclosing the Wee Bankie fishing grounds off the entrance to the Firth of Forth, south-east Scotland.

192

Figure 14.5. The Isle of May, the Wee Bankie study area and the area of sea off east Scotland and north-east England closed to commercial sandeel fishing since 2000.

193

Figure 14.6. The total annual landings and estimated spawning stock biomass of sandeels in the North Sea.

193

CHAPTER 15 Figure 15.1. Proposed areas for the location of wind farms in the entrance to the Firth of Forth south-east Scotland.

197

Figure 15.2. The running 5 year average sea surface temperature (SST) anomaly relative to 1961–90 for 1850–2008 for the North Atlantic south to 25°N, excluding the Mediterranean.

199

Figure 15.3. The past and future occurrence of breeding Puffins in 50 x 50km coastal grid squares.

200

10

List of Tables CHAPTER 3 Table 3.1.

Number of grooves on the bills of Puffins of known age and individuals definitely breeding on the Isle of May.

32

Measurements and weights of breeding male and female Puffins on the Isle of May.

33

Table 3.3.

The roles of the sexes in the Puffin during the breeding season.

34

Table 3.4.

Monthly weights of Puffins on the Isle of May.

35

Table 3.2.

Table 3.5.

Plumages of adult Puffins at sea off east Britain in 1985.

36

Table 3.6.

The state of the primaries of adult Puffins found dead on the coasts of the North Sea and the Northern Isles or shot in the Faeroe Islands.

37

Table 3.7.

The percentage of Puffins on the Isle of May during late March and the first two weeks of April that retained some black winter feathers on the face.

38

Table 3.8.

Timing of primary moult of Puffins from east Scotland hatched in 1972 and raised in captivity in the Netherlands.

39

CHAPTER 4 Table 4.1.

Changes in the numbers of pairs of Puffins in Britain, Ireland and France between 1969–70 and 1998–2002 and an assessment of changes since.

57

CHAPTER 6 Table 6.1.

Dates when known-aged immature Puffins ringed as chicks were first seen ashore on the Isle of May.

73

Table 6.2.

The percentages of immature Puffins on the Isle of May, 1976–2010.

74

Table 6.3.

Burrow and mate fidelity of Puffins on the Isle of May between 1990 and 2002.

76

CHAPTER 7 Table 7.1.

Weights and ages at peak weight and fledging of manipulated and unmanipulated young Puffins.

95

Effect on feeding frequency of giving Puffin chicks additional food or playing a begging call when an adult enters the burrow.

96

Table 7.3.

Breeding success of Puffins at British colonies.

98

Table 7.4.

Dates when known aged and adult Puffins were last seen ashore on the Isle of May.

Table 7.2.

101

11

THE PUFFIN

CHAPTER 9 Table 9.1.

Lengths of young fish brought to young auks on the Isle of May in 2005 and 2006.

115

Table 9.2.

Fish recorded being brought to young Puffins.

119

Table 9.3.

Weight to length relationships of fish species likely to be eaten by young Puffins.

120

Calorific values of fish collected from Puffins and Common Guillemots feeding chicks on the Isle of May.

126

Wrecks of Puffins in the east Atlantic and Mediterranean.

137

Table 9.4. Table 9.5.

CHAPTER 10 Table 10.1. Percentages of loads of fish brought to young Puffins that were stolen by gulls.

143

CHAPTER 11 Table 11.1. Survival rates of adult Puffins in the east and west Atlantic.

154

CHAPTER 14 Table 14.1. Method of recovery (where known) of Puffins ringed in Britain and Ireland in relation to age at recovery and where recovered.

184

Table 14.2. Concentrations of chemicals in livers of Puffins in 1969–79.

185

Table 14.3. Concentrations of cadmium in the livers of Puffins found dead and killed in Britain in 1977–82.

186

Table 14.4. Concentrations of mercury, PCBs, DDE and dieldrin in Puffin eggs in 1969–79.

186

Table 14.5. Numbers of Puffins on North Sea coasts with and without artefacts in their stomachs in relation to year, age and whether they had been found dead or killed.

190

12

Introduction and acknowledgements This book was originally conceived as ‘a little ploy to occupy Mike in his retirement’. His original Poyser book The Puffin, which was published in 1984, attempted to bring together what was known about the species up to the early 1980s but has been out of print for many years. Moreover, since then much more has been discovered about many aspects of Puffin biology. Some of this new information has come from the Isle of May, a small island off the coast of south-east Scotland, where Mike started his work on Puffins in 1972. Ten years later, Sarah became involved in the study and since then the work has been very much a joint effort. As with the research, so with the writing of this book which has gradually evolved into a joint venture – hence the shared authorship. Although much of the information presented is based on our own work and experiences, we have tried to avoid it being too ‘Isle-of-May-centric’ and where appropriate have incorporated findings from many other studies elsewhere in Europe and North America. Atlantic Puffins (shortened to Puffins later unless there is a possibility of confusion with Horned or Tufted Puffins) are challenging birds to study. They not only live in some of the remotest parts of the North Atlantic but much of their life on land goes on underground and they do not take kindly to too much disturbance. Until recently, what we knew about their lives came from watching them at colonies, catching adults and chicks and marking them with rings to find out how well they survived from one year to the next, how old they were when they first bred, and for the very few that were reported away from the colony, where they were found dead. Although we knew that Puffins fed their chicks on small fish, we had no idea where or how they caught their prey. Perhaps more importantly, we did not know where they went and what they did in the winter when they disappeared for seven or eight months. Some of the most exciting new results in this book were obtained in the last few years using a variety of miniature bird-borne logging devices that are now providing tantalising glimpses into the Puffin’s life at sea. Such information is urgently needed as pressure on the marine environment intensifies. While this book uses the 1984 volume as its foundation and much of the original information is included, our intention has been to bring the story up to date, giving prominence to new discoveries as well as highlighting the important gaps in our knowledge. It is written for ornithologists in general and puffin enthusiasts in particular. We have tried to keep statistics to a minimum and use the term significant only in its statistical sense to indicate that the result is unlikely to have occurred by chance. Anyone with a detailed interest in a specific topic should be able to track down the original data or research from the reference lists and appendices.

13

THE PUFFIN

In the course of writing this book, we have been in contact with hundreds of people who have patiently answered our questions and generously allowed us access to unpublished data. We have tried to give credit where it is due without overburdening the text with citations but we apologise for any omissions or oversights. Special thanks are due to (in alphabetical order) Tycho Anker-Nilssen, Rob Barrett, Tim Birkhead, Alexander Bond, Andre Breton, Kees Camphuysen, Tony Diamond, Kjell Einar Erikstad, Bob Furness, Stefan Garthe, Martin Heubeck, Mike Hornung, Jens-Kjeld Jensen, Alan Knox, Stephen Kress, José Lahoz-Monfort, Karen McCoy, Roddy Mavor, Ian Mitchell, Vivian Nutton, Matt Parsons, Sergio Pereira, Debbie Russell, Sabine Schmitt, Kees Swennen, Mark Tasker, Kenny Taylor, Andy Webb and Bernie Zonfrillo for supplying details of their own research and/or commenting on various parts of the book. The chapter on the Puffin’s distribution abroad would have been impossible without detailed input from Tycho Anker-Nilssen (Norway), Matti Åhlund and Rune Hixén (Sweden), Bernard Cadiou and Mélanie Le Nuz (France), Erik Mortensen and Jens-Kjeld Jensen (Faeroes), Aevar Petersen and Erpur Hansen (Iceland), Hallvard Strøm (Svalbard, Russia and Jan Mayen), David Boertmann (Greenland) and Tony Diamond, Tony Gaston and Jean-François Rail (North America). Over the years Stuart Murray, Kenny Taylor, Alan Leitch, Chris Wernham, John Calladine, Suki Finney, Jenny Bull, Linda Wilson, Mark Newell, Sheila and Debbie Russell have made major contributions to the fieldwork. We are also grateful to the many inhabitants of the Mouse House and Fluke Street, visitors to the Isle of May Bird Observatory, and Nature Conservancy Council and Scottish Natural Heritage staff who found the time to get involved with various aspects of Puffin work. Jimmy Smith and Andy Easton transported us safely to and from the island in Breadwinners I, II and III. Peter Rothery and Morten Frederiksen provided statistical help and David Jenkins and John Hislop read the whole manuscript and made valiant attempts to improve our English. The Nature Conservancy Council and its successor Scottish Natural Heritage allowed us to work on the Isle of May for almost 40 years. During this period, we have been employed by, or had emeritus status at, the Institute of Terrestrial Ecology and its successor, the Centre for Ecology & Hydrology. We very much appreciate the support we have received from successive directors and the countless discussions we have had with colleagues at Banchory and more recently Edinburgh. Francis Daunt, Maria Bogdanova and Sue Lewis provided invaluable help with the Isle of May logger work and production of the figures. The recoveries of Puffins ringed in Britain and Ireland were supplied by the British Trust for Ornithology, the densities of Puffins at sea came from the database of the European Seabirds at Sea Specialists Group and results of the annual February Beached Bird Survey from the Royal Society for the Protection of Birds. Over the years, the Puffin work has received financial support from the Natural Environment Research Council, the Seabird Monitoring Programme of the Joint Nature Conservation Committee, the World Wildlife Fund, British Petroleum and Scottish Natural Heritage. We thank the many people who allowed us to see their photographs and Anke Addy for processing some of the files. Making the final selection was extremely difficult and we would have liked to include many more images than appear in the book. Last, but not least, we have been extremely lucky to have Keith Brockie do the illustrations.

14

CHAPTER 1

Puffins and auks The first detailed description of the Atlantic Puffin was made by John Caius in 1570. His original text was in Latin and the following translation is from Evans (1903): ‘There is a certain sea-bird of our country, in size and form of body like a little Duck with webbed and reddish feet, placed nearer to the hinder parts than in other web-footed kinds except the Pygosceles [penguins]: with a somewhat thin beak, rather more extended in breadth vertically than stretching laterally to a very great length, furrowed by four red grooves above, and two below, pale ochre in colour. The part lying between these and the head is bluish, and of such a shape as is the moon, when ten days have elapsed from conjunction. The bird is black on the upper surface of the whole body, save where the eyes are set, which are enclosed in white; but is wholly white below, save on the upper breast, where it is black. It gets its living from the sea. This bird our people call the Puphin, we say Pupin from its ordinary cry of ‘pupin’. It hides in holes in the ground … And so is driven out from a Rabbit’s burrow by a ferret turned in by any hunter in a place situated not far from the sea. It is used as fish among us during the solemn fast of Lent: being in substance and taste not unlike a seal. It is a gregarious animal, and has its proper time for lying hidden, as the Cuckoo and the Swallow. It lays for the most part two eggs in Rabbit burrows in the earth… I kept one in my house for eight months. It bit with right good will those who supplied it with food or touched it, but in a mild and harmless way.’ Caius was obviously familiar with the Puffin, although we now know that it lays one not two eggs, disappears out to sea outside the breeding season rather than hibernating and most people would consider its bite painful rather than mild. He sent this description and a drawing to Gessner who, in his Historia animalium (1551–58), changed it to ‘If you imagine that this bird was white, and had then put on a black cloak with a cowl, you would give this bird the name of Little Friar of the sea (fratercula marina)’. This upset Caius who considered it frivolous and struck the remark out of his own copy of that book (Nutton 1985). Puphin, or some variant from the verb puff which means to become swollen, appears to have been used from at least 1287, although originally it referred to the very fat young shearwaters that were salted and traded as food. This explains the considerable confusion between the names of the puffin and shearwater (the French name for the Manx Shearwater is Puffin d’anglais and its scientific name is Puffinus puffinus). To add further confusion, in 1666 Merrett in his Pinax rerum naturalium britannicarum gives the Puphin as Puphinus Anglicus (Bircham 2007) and the Black Guillemot was sometimes known at the Puffinet (Lockwood 1984).

15

THE PUFFIN

THE AUKS The Atlantic Puffin and its sister species the Horned Puffin in the Pacific are perhaps the most widely recognised members of the auk family (Alcidae). There are no auks in the southern hemisphere, and conversely no penguins or diving-petrels in the northern hemisphere. The resemblance of the larger auks to penguins and the smaller auks to diving-petrels is due to convergent evolution, a process whereby taxonomically unrelated birds are moulded to a similar appearance by similar environmental pressures. Today, these groups of marine birds that both use their wings for underwater propulsion occupy similar ecological niches in the two hemispheres. However, no penguin has developed such an elaborate bill as a Puffin, although the crested penguins have gone in for flamboyant head plumes such as are found in some auklets. The Atlantic Puffin is one of four species of puffin that belong to the Alcidae which include 23 living and one recently extinct species. Twenty-one species occur in the North Pacific, of which 17 are endemic. This compares with just two endemics in the North Atlantic – the Atlantic Puffin and Razorbill (three if we include the extinct Great Auk). Common and Brünnich’s Guillemots are common in both oceans but the Pacific populations of Little Auks and Black Guillemots are extremely small. The very rough population estimates suggest that approximately similar numbers of auks occur in the two oceans and the Atlantic Puffin accounts for the bulk of the world’s puffins.

EVOLUTION OF THE AUKS Much has been written on the origin and evolution of the auks (e.g. Udvardy 1963, Bédard 1969). The early studies depended on evidence from morphology, fossils and biogeography but in recent years DNA analysis has allowed more objective judgments to be made (details in Pereira & Baker 2008). The Alcidae appear to have originated, and initially evolved, in the temperate or subtropical parts of the Pacific and only later did these early species become adapted to cold waters. Auks could have entered the Atlantic by either of the obvious Arctic routes around the top of North America and/or Eurasia after they became cold tolerant, or the now less obvious southern way before the uprising of the Isthmus of Panama prevented free movement between the oceans. Both routes were probably used, with the ancestors of Common and Brünnich’s Guillemots, Razorbill and Little Auk taking the southern route while the ancestors of Atlantic Puffin and Black Guillemot moved very much later via the northern route when the Bering Strait became ice-free during the Pliocene and Pleistocene. As suggested by the morphology of the birds and confirmed by DNA analysis, the Atlantic and Horned Puffins are much more closely related to each other than to the Tufted Puffin and Rhinoceros Auklet (Friesen et al. 1996). The separation of the Atlantic and Horned Puffins took place less than 5 million years ago; their ancestor diverged from the Tufted Puffin about twice as long ago and from the Rhinoceros Auklet six times as far back in the past. It is, however, hard to know whether the geographical isolation of the ancestors of the Atlantic and Horned Puffins resulted in the two becoming separate species, or if they were distinct before the Atlantic Puffin moved into the Atlantic. Auks still move between the Pacific and Atlantic, albeit extremely rarely. Several Pacific species have been seen in the Atlantic or adjacent waters in historic times with records of Tufted Puffins in Maine (obtained and painted by Audubon), Sweden, south-west Greenland and most recently, off south-east England. A Parakeet Auklet has been seen in Sweden, a Crested Auklet off Iceland and a Long-billed Murrelet off southern England. Auks are resilient birds and it cannot be assumed that any individual that turns up in the wrong ocean is doomed to an early death. A single adult Ancient Murrelet, a widespread species in both the eastern and western Pacific, was present among other auks on Lundy, south-west England, during the summers of 1990–92 (Waldon 1994). Given the decreasing amounts of ice around the northern edges of North America and Asia it is probably only a matter of time before Horned Puffins reach the Atlantic or Atlantic Puffins reach the Pacific.

16

Puffins and auks

PUFFINS AS A GROUP This book is concerned mostly with the Atlantic Puffin. However, for the sake of completeness brief summaries (from Gaston & Jones 1998, Piatt & Kitaysky 2002a,b) of the appearance, distribution and population sizes of the four puffin species are given below.

Atlantic Puffin The Atlantic Puffin stands 18–20cm high and weighs 350–600g. It is black above and white below with large and well-defined white or grey face patches. The beak is large, laterally compressed and brightly coloured with a series of grooves in the outer part. A full description is given in Chapter 3. The Atlantic Puffin breeds from France and the Gulf of Maine in the south to as far north as there is ice-free land and has been studied throughout its range. It winters over vast areas of the North Atlantic and, in small numbers, the Mediterranean (Figure 1.1). It is the most numerous of the four puffins with some 20 million individuals. The single egg is incubated for six weeks and the chick is fed on small fish for another six weeks. The chick is independent after it has fledged.

Horned Puffin Slightly larger than the Atlantic Puffin and weighing 500–650g, the Horned Puffin has blackish upperparts, white underparts and sides to the head, and a large, brightly coloured beak. The main differences between this species and the Atlantic Puffin are the pointed fleshy protuberances above each eye which point devilishly to the sky, and the inner two-thirds of the upper and lower bill which are creamy yellow, the outer part being red with the usual grooves. The legs and feet are orange.

Figure1.1. The colonies where the major studies of Atlantic Puffins have been carried out and the approximate southern limit of the distribution in winter.

17

THE PUFFIN

Figure 1.2. The three puffins in the Pacific – Tufted Puffin (top), Horned Puffin (mid) and Rhinoceros Auklet (bottom).

The species has a more northerly distribution than the Tufted Puffin, although the two species occur together over more than half the breeding range, breeding from the Arctic south to Japan and British Columbia. Most Horned Puffins winter well offshore in the central North Pacific. There are about one million individuals, with 86% in North America. The Horned Puffin generally nests among rocks or in cracks in the cliffs. The single egg is incubated for six weeks and the chick fed for another six weeks on fish and squid caught relatively close to the colonies.

Tufted Puffin This is the largest puffin, standing some 30cm high and weighing 750–850g, and by far the most strikingly marked. The bird is all-dark, except in summer when the forehead and cheeks are white and there are spectacular long white or yellow tufts of feathers drooping down behind the eye and curling onto the shoulders. In the winter, the face becomes grey-brown and the plumes are lost. The legs, feet, eye-ring and bill are startlingly orange or reddish-orange, the base of the upper mandible is greenish and the outer part has several very distinct grooves which curve the opposite way to those on the bill of the Atlantic Puffin. The Tufted Puffin is the commonest puffin in the Pacific with 3 million birds (82% in North America). Breeding colonies occur on both sides of the Pacific from the Arctic south to Hokkaido Island in Japan and to the warm waters of California. Wintering areas are located in the deep oceanic waters of the central North Pacific. Birds typically breed in earth burrows near the cliff edge, partly because it is easy to dig there and partly because these are the heaviest of the puffins and have difficulty in taking off from flat ground. The colonies are sometimes very large, with many tens of thousands of pairs. The biology is ‘typically puffin’ – a single egg incubated for six weeks and the young fed on fish and squid (sometimes caught well away from the colonies) for six to seven weeks before fledging, after when the juvenile is independent. Adults eat mainly squid and planktonic invertebrates.

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Puffins and auks

Rhinoceros Auklet Adults of this species weigh 450–550g and have upperparts that are sooty-black and a whitish belly. The upper breast, throat and sides of the body are brown-grey giving the bird a slightly dirty appearance. Its bill is not as flattened or as deep as other puffins nor does it have grooves, but in the breeding season it has a large ‘horn’ pointing upwards and slightly forward from the base of the upper mandible. The breeding plumage is completed by two sets of whitish plumes, one set behind each eye, the other just below the gape. Rhinoceros Auklets breed in large colonies in two separate areas – the Gulf of Alaska south to California (where there are only a few hundred birds) and from the western end of the Aleutian chain down the coast of Asia to Japan. The total population is about 1.25 million breeding birds. It winters inshore, just to the south of the breeding range. Unlike other puffins, this species is mainly nocturnal at the colony, visiting its burrow, which is dug in soft soil among dense vegetation or in a cave, at night. Apparently, it is then safe from predatory gulls while crashing into, or floundering among, the bushes and tall herbs. The single egg is incubated for six weeks and the young fed at a lower rate than normal for the other puffins, so that it grows more slowly and fledges when seven to eight weeks old.

TAXONOMY OF THE ATLANTIC PUFFIN Although the Atlantic Puffin breeds over a wide area, there are no obvious geographic differences in plumage. Birds in the north of the range are, however, large compared to those in the south (Figure 1.3). This latitudinal pattern is apparent in many taxa and is known as Bergman’s rule. On average, a Puffin in southern Britain has a wing length of 158mm and weighs c.400g whereas comparable measurements for a bird in Spitsbergen are 184mm and c.600g. However, there is considerable variation in the size of Puffins at any colony and some adults on the Isle of May are larger than the average at some colonies in northern Norway. It is therefore difficult to predict where any individual Puffin might have come from with any certainty. Puffins from western Atlantic colonies are generally larger than those from British and Faeroese colonies at the equivalent latitude. This is consistent with the idea that latitude is a proxy for temperature since conditions at similar latitudes are markedly colder in the west Atlantic compared to the east. One would expect cold-water Puffins to be larger than those in warmer climes since larger size reduces the ratio of body surface area to mass and so reduces heat loss. Some birdwatchers and even serious ornithologists become upset if the name of a well-known bird is changed and mutter about ‘splitters’ (taxonomists who divide one former species into several new ones) or

Figure 1.3. The increase in wing length of adult Puffins with latitude of the colony in the east and west Atlantic. Both relationships are significant (r = 0.91, p