The Handbook of New Zealand Mammals 9781486306282, 9781486306299, 9781486306305, 9781988592589

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THIRD EDITION

The Handbook of New Zealand

Mammals

Editors: Carolyn M King and David M Forsyth

The Handbook of New Zealand

Mammals Third Edition

Editors: Carolyn M King and David M Forsyth

otago university pres s Te Whare Tā o Te Wānanga o Ōtākou

Copyright The Authors 2021. All rights reserved. Except as permitted by applicable copyright laws, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, duplicating or otherwise, without the prior permission of the copyright owner. Contact CSIRO Publishing for all permission requests. The authors and editors assert their moral rights, including the right to be identified as an author or editor. A catalogue record for this book is available from the National Library of Australia. ISBN: 9781486306282 (hbk) ISBN: 9781486306299 (epdf) ISBN: 9781486306305 (epub) Published in Australia in print only, and in all other formats throughout the world, by CSIRO Publishing. CSIRO Publishing Locked Bag 10 Clayton South VIC 3169 Australia Telephone: +61 3 9545 8400 Email: [email protected] Website: www.publish.csiro.au A catalogue record for this book is available from the National Library of New Zealand. ISBN 978-1-98-859258-9 Published in New Zealand and the rest of the world (excluding Australia), in print only, by Otago University Press. Otago University Press Te Whare Tā o Te Wānanga o Ōtākou 533 Castle Street Dunedin, New Zealand [email protected] www.otago.ac.nz/press Front cover: brushtail possum, grey form; lesser short-tailed bat; New Zealand fur seal (artwork by Priscilla Barrett) Back cover: Himalayan tahr male, winter (artwork by Priscilla Barrett) Edited by Joy Window (Living Language) Cover design by James Kelly Typeset by Envisage Printed in China by Leo Paper Products Ltd. CSIRO Publishing publishes and distributes scientific, technical and health science books, magazines and journals from Australia to a worldwide audience and conducts these activities autonomously from the research activities of the Commonwealth Scientific and Industrial Research Organisation (CSIRO). The views expressed in this publication are those of the author(s) and do not necessarily represent those of, and should not be attributed to, the publisher or CSIRO. The copyright owner shall not be liable for technical or other errors or omissions contained herein. The reader/user accepts all risks and responsibility for losses, damages, costs and other consequences resulting directly or indirectly from using this information. The paper this book is printed on is in accordance with the standards of the Forest Stewardship Council® and other controlled material. The FSC® promotes environmentally responsible, socially beneficial and economically viable management of the world’s forests.

Contents Preface to the Third Edition

vii

Contributors to the Third Edition

ix

Acknowledgements

xi

Editors’ introduction

xiv

Preamble to species accounts

1

Family Macropodidae

xxxvi

1

A.D.M. Latham, B. Warburton Dama wallaby

2

Bennett’s wallaby

8

Parma wallaby

14

Black-striped wallaby

17

Brush-tailed rock-wallaby

18

Swamp wallaby

21

References 23

2

Colour plates

27

Family Phalangeridae

43

P.E. Cowan, A.S. Glen

3

Brushtail possum

43

References

65

Family Erinaceidae

79

C. Jones

4

European hedgehog

79

References

90

Families Vespertilionidae and Mystacinidae

95

C.F.J. O’Donnell, K.M. Borkin, S. Parsons, C. Toth New Zealand long-tailed bat

96

Lesser short-tailed bat

108

Greater short-tailed bat

122

References 124

5

Family Leporidae

131

G.L. Norbury, J.A. Duckworth, J.E.C. Flux European rabbit

131

Brown hare

146

References 152

iv

The Handbook of New Zealand Mammals

6

Family Muridae

161

J.M. Wilmshurst, W.A. Ruscoe, J.C. Russell, J.G. Innes, E.C. Murphy, H.W. Nathan Kiore, Pacific rat

162

Norway rat

183

Ship rat

193

House mouse

207

References 221

7

Families Otariidae and Phocidae

241

B.L. Chilvers, R.G. Harcourt Family Otariidae

241

New Zealand fur seal

243

Subantarctic fur seal

249

New Zealand sea lion

250

Family Phocidae

255

Southern elephant seal

255

Weddell seal

260

Leopard seal

263

Crabeater seal

265

Ross seal

266

References 268

8

Family Canidae

279

G.R. Clark, K. Greig Kurı¯

279

References 283

9

Family Mustelidae

285

C.M. King, A.J. Veale, E.C. Murphy, P. Garvey, A.E. Byrom Stoat

285

Weasel

309

Feral ferret

316

References 329

10

Family Felidae

343

C. Gillies, Y. van Heezik Feral cat

343

References 364

11

Family Equidae

371

E.Z. Cameron Feral horse

371

References 376

Contents

12

Family Suidae

379

J.C. McIlroy, G. Nugent Feral pig

379

References 388

13

Family Bovidae

393

J.P. Parkes, D.M. Forsyth, K.G. Tustin Feral cattle

393

Alpine chamois

398

Himalayan tahr

405

Feral goat

417

Feral sheep

432

References 437

14

Family Cervidae

447

G. Nugent, D.M. Forsyth, A.D.M. Latham, C. Speedy, R.B. Allen, G.W. Asher, K.G. Tustin Western red deer

449

Wapiti

467

Sika deer

474

Sambar deer

480

Rusa deer

486

Chital deer

492

Common fallow deer

493

White-tailed deer

504

Moose

510

References

514

Glossary and abbreviations

528

Key to skulls

532

Index to animal species

534

v

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Preface to the Third Edition HISTORY The Handbook of New Zealand Mammals was first published by Oxford University Press (Auckland) in New Zealand’s sesquicentennial year of 1990, and launched at a celebration funded by the 1990 Commission in W ­ ellington. The Handbook followed 40 years after the first substantial book about mammals in New Zealand, Introduced Mammals of New Zealand: An Ecological and ­Economic Survey by Kazimierz Wodzicki, which was published in 1950. Ten years after the first edition of The Handbook of New Zealand Mammals, a series of reviews was commissioned, and published under the general heading of Advances in New Zealand Mammalogy 1990– 2000 as a special issue of the Journal of the Royal Society of New Zealand in 2001. Fifteen years after the first edition, a full second edition integrated and further updated the 1990 and 2001 texts. Now, a further 15 years later, we have revisited and updated the texts for a third edition, scheduled to appear in early 2021. As a comprehensive reference book, the first Handbook was cast in the same mould as Wodzicki’s pioneering volume, but different from it in one important aspect: the inclusion of introduced and native mammals in the same tome. There were objections to this decision from conservation activists, on the grounds that it seemed to extend a tacit acceptance of the introduced species. However, the practical and scientific reasons for including native and introduced species together won the debate. The ready reception and wide use of the book since then has confirmed that view. The first edition of the Handbook was reprinted as a paperback, with minor corrections, in 1995, and again, in new covers, in 1998. Oxford University Press in Auckland and (after 1999) in Melbourne published the first and second editions. The third edition has been prepared by CSIRO Publishing in Melbourne. The extensive information collected by the authors for each edition includes much material previously unpublished or gathered from inaccessible or widely scattered sources. The combined literature list for the first edition (~1600 entries) closed in September 1987, when the paper manuscript was handed over to the publisher (a few later citations were added in proof). The combined list for the second edition totalled almost 3000 entries, and closed in

late 2004. The lists for the third edition are now separated into family sections. This rapid increase in information to be reviewed, and in the speed of handling it, reflects the many exciting advances in technology that have accompanied the electronic revolution of the last 30 years.

AIMS AND LIMITATIONS The Handbook of New Zealand Mammals has always had two aims: first, to collate for convenient reference authoritative, fully documented descriptions of all the landbreeding mammals that are or have been resident in New Zealand; and, second, to stimulate new research. Many hypotheses suggested in earlier editions have since been tested. Some ideas developed overseas can be more effectively investigated in New Zealand than elsewhere; nevertheless, some questions of taxonomy or even basic biology remain to be examined. Readers might also detect differences of opinion between contributors, which have been allowed to stand because they can be resolved only by further research. Island distributions are often dynamic, especially for species that are good swimmers, so the listings of island distributions are here mostly confined to islands of >5 ha supporting more or less permanent populations. No doubt many such populations remain unlisted, because it is simply impossible to do enough regular surveys to find them all. The Handbook of New Zealand Mammals is not, however, an introduction to the biology of mammals in general, which is better described in a general reference work or a field guide. Neither is it a compendium of techniques for the study of mammals, for which readers should follow up the detailed references given in the species accounts.

COVERAGE All known land-breeding mammals that are or have been recorded in the wild in the New Zealand region (including the Ross Dependency, Antarctica) are described, including introductions that survived for at least 25 years but have since become extinct (kurī, black-striped ­wallaby, chital deer); and feral populations of domestic stock that are or have been established for that long.

viii

The Handbook of New Zealand Mammals

One failed native vagrant, the little red flying fox, is mentioned in its family context (Chapter 4). Species known to have landed in New Zealand before 1910 but never released in the wild may be mentioned but not described. These include (1) non-native mammals confined to zoos, experimental farms or other premises, e.g. Père David’s deer, alpacas and llamas, and chinchillas; and (2) failed introductions (e.g. mongoose), except as mentioned under the appropriate family or genus headings and listed in the Editors’ Introduction. Excluded are (1) the cetaceans (whales and dolphins), because this special group is well catered for elsewhere;

(2) controlled farm stock and pets (such as sheep, goats, cattle, donkeys, horses, working and town dogs, house cats, guinea-pigs, fancy rabbits); and (3) the mythical ‘New Zealand otter’ (Chapter 9).

CORRECTIONS AND ADDITIONS Every effort has been made to check all information given here. The editors and publisher would be grateful to hear of any errors or omissions, which can be corrected in the next edition.

Contributors to the Third Edition Allen, R.B. Independent Researcher, Lincoln, New Zealand

Harcourt, R.G. Department of Biological Sciences, Macquarie University, Sydney, Australia

Asher, G.W. AgResearch, Mosgiel, New Zealand

Innes, J.G. Manaaki Whenua – Landcare Research, Hamilton, New Zealand

Borkin, K.M. Department of Conservation, Rotorua, New Zealand Byrom, A.E. Manaaki Whenua – Landcare Research, Lincoln, New Zealand Cameron, E.Z. School of Biological Sciences, University of Canterbury, New Zealand Chilvers, B.L. School of Veterinary Science, Massey University, New Zealand Clark, G.R. Australian National University, Canberra, Australia Cowan, P.E. Manaaki Whenua – Landcare Research, Lincoln, New Zealand Duckworth, J.A. Manaaki Whenua – Landcare Research, Lincoln, New Zealand Flux, J.E.C. 23 Hardy Street, Waterloo, Lower Hutt, New Zealand Forsyth, D.M. NSW Department of Primary Industries, Orange, Australia Garvey, P. Manaaki Whenua – Landcare Research, Lincoln, New Zealand Gillies, C.A. Department of Conservation, Hamilton, New Zealand Glen, A.S. Manaaki Whenua – Landcare Research, Auckland, New Zealand Greig, K. Department of Anthropology and Archaeology, University of Otago, New Zealand

Jones, C. Manaaki Whenua – Landcare Research, Lincoln, New Zealand King, C.M. School of Science, University of Waikato, Hamilton, New Zealand Latham, A.D.M. Manaaki Whenua – Landcare Research, Lincoln, New Zealand Murphy, E.C. Department of Conservation, Christchurch, New Zealand McIlroy, J.C. Independent Researcher, Akaroa, New Zealand Nathan, H.W. Zero Invasive Predators, Wellington, New Zealand Norbury, G.L. Manaaki Whenua – Landcare Research, Alexandra, New Zealand Nugent, G. Manaaki Whenua – Landcare Research, Lincoln, New Zealand O’Donnell, C.F.J. Department of Conservation, Christchurch, New Zealand Parkes, J.P. Kurahaupo Consulting, Christchurch, New Zealand Parsons, S. School of Biology and Environmental Science, Queensland University of Technology, Brisbane, Australia Ruscoe, W.A. CSIRO, Canberra, Australia Russell, J.C. School of Biological Sciences, University of Auckland, New Zealand

x

The Handbook of New Zealand Mammals

Speedy, C. Wildlife Management Associates Ltd, Turangi, New Zealand Toth, C. Canadian Wildlife Service, Environment and Climate Change Canada, Canada Tustin, K.G. Independent Researcher, Te Anau, New Zealand van Heezik, Y.M. Department of Zoology, University of Otago, New Zealand Veale, A.J. Manaaki Whenua – Landcare Research, Auckland, New Zealand Warburton, B. Manaaki Whenua – Landcare Research, Lincoln, New Zealand Wilmshurst, J.M. Manaaki Whenua – Landcare Research, Lincoln, New Zealand

CITATION Individual contributions to this book may be cited in the literature in the format given at the end of each species account. For example: O’Donnell CFJ, Borkin KM (2021) Chalinolobus tuberculatus. In The Handbook of New ­Zealand Mammals 3rd edn. (Eds CM King and DM ­Forsyth) Families Vespertilionidae and Mystacinidae, pp. 95–130. CSIRO Publishing, Melbourne.

Acknowledgements As during the preparations of both previous editions, the authors of the separate chapters in this book have drawn heavily on unpublished data and reports from various official and private sources, and have cooperated between themselves in exchanging data, observations, information, illustrations, criticism, copyright permissions, and other kinds of help. The authors are all indebted to those whose contributions were especially helpful for their own chapters, as listed in the figure captions and the references. In addition, the authors or their informants received field support and assistance from various organisations and funding agencies, without whose help our knowledge of the biology of mammals in New Zealand would be

much the poorer. Our collective debt to graduate students is especially clear from the number of theses cited. All the authors past and present, and the current referees, are acknowledged below as part of this ongoing collective enterprise, because there is no clear distinction between their contributions, and their collective expertise is the reason that this book has remained in print continuously since 1990 and has proved to be such an important work of reference. For the third edition, authors of the previous texts are named at the end of each chapter as authors of the new edition if they have actively worked on the new manuscripts. We gratefully acknowledge the efforts of all the other first- and second-edition authors, who helped lay the foundations of this edition.

Authors contributing to all editions, and referees for the 3rd edition Authors (1st edition, 1990)

Authors (2nd edition, 2005)

Authors (3rd edition, 2021)

Referees (3rd edition, 2021)

Wallabies

B. Warburton R.M.F. Sadleir

B. Warburton

A.D.M. Latham B. Warburton

M. Eldridge

Brushtail possum

P.C. Cowan

P.C. Cowan

P.C. Cowan A.S. Glen

M.C. Clout

Hedgehog

R.E. Brockie

C. Jones M.D. Sanders

C. Jones

G. L. Norbury

Long-tailed bat

M.J. Daniel

C.F.J. O’Donnell

C.F.J. O’Donnell K.M. Borkin

J.E. Christie

Short-tailed bats

M.J Daniel

B.D. Lloyd

S. Parsons C. Toth

J.E. Christie

Rabbit

J.A Gibb J. M. Williams

G.L. Norbury B. Reddiex

G.L. Norbury J.A. Duckworth

J.P. Parkes

Brown hare

J.E.C. Flux

G.L. Norbury J.E.C. Flux

G.L. Norbury J.E.C. Flux

J.P. Parkes

Kiore

I.A.E. Atkinson H. Moller

I.A.E. Atkinson D.R. Towns

J.M. Wilmshurst W.A. Ruscoe

T.F.G. Higham

Norway rat

P.J. Moors

J.G. Innes

J.C. Russell J.G Innes

G.A. Harper

Ship rat

J.G Innes

J.G. Innes

J.G. Innes J.C. Russell

G.A. Harper

House mouse

E.C Murphy C.R. Pickard

W.A. Ruscoe E.C. Murphy

E.C. Murphy H.W. Nathan

A.J. Veale

New Zealand fur seal

M.C. Crawley

R.G. Harcourt

B.L. Chilvers R.G. Harcourt

R.H. Taylor L. Meynier

Species

Continued

xii

The Handbook of New Zealand Mammals

Authors contributing to all editions, and referees for the 3rd edition  (Continued)

Species

Authors (1st edition, 1990)

Authors (2nd edition, 2005)

Authors (3rd edition, 2021)

Referees (3rd edition, 2021)

Subantarctic fur seal

M.C. Crawley

R.G. Harcourt

B.L. Chilvers R.G. Harcourt

R.H. Taylor C.R. McMahon

New Zealand sea lion

M.C. Crawley

R.G. Harcourt

B.L. Chilvers R.G. Harcourt

R.H. Taylor L. Meynier

Southern elephant seal

M.C. Crawley

R.G. Harcourt

R.G. Harcourt B.L. Chilvers

R.H. Taylor C.R. McMahon

Weddell seal

M.C. Crawley

R.G. Harcourt

R.G. Harcourt B.L. Chilvers

R.H. Taylor C.R. McMahon

Leopard seal

M.C. Crawley

R.G. Harcourt

R.G. Harcourt B.L. Chilvers

R.H. Taylor C.R. McMahon

Crabeater seal

M.C. Crawley

R.G. Harcourt

R.G. Harcourt B.L. Chilvers

R.H. Taylor C.R. McMahon

Ross seal

M.C. Crawley

R.G. Harcourt

R.G. Harcourt B.L. Chilvers

R.H. Taylor C.R. McMahon

Kur ı¯

A. Anderson G.R. Clark

G.R. Clark

G.R. Clark K. Greig

J.R. Wood

Stoat

C.M. King

C.M. King E.C. Murphy

C.M. King A.J. Veale

P.M. Garvey

Weasel

C.M. King

C.M. King

C.M. King E.C. Murphy

P.M. Garvey

Ferret

R.B. Lavers B.K. Clapperton

B.K. Clapperton A. Byrom

A.E. Byrom P.M. Garvey

C.A. Gillies

Cat

B.M. Fitzgerald

C.A. Gillies B.M. Fitzgerald

C.A. Gillies Y.M. van Heezik

A.S. Glen

Feral horse

R.H. Taylor

C.J. Veltman

E.Z. Cameron

R.H. Taylor C.M. King

Feral pig

J.C. McIlroy

J.C. McIlroy

J.C. McIlroy G. Nugent

C.R. Krull

Feral cattle

R.H. Taylor

J.P. Parkes

J.P. Parkes

R.H. Taylor

Alpine chamois

C.M.H. Clarke

D.M. Forsyth

D.M. Forsyth

K.G. Tustin

Himalayan tahr

K.G. Tustin

D.M. Forsyth K.G. Tustin

D.M. Forsyth K.G. Tustin

J.P. Parkes

Feral goat

M.R. Rudge

J.P. Parkes

J.P. Parkes

M.R. Rudge

Feral sheep

M.R. Rudge

J.P. Parkes

J.P. Parkes

M.R. Rudge D.R. Scobie

Western red deer

C.N. Challies

G. Nugent K.W. Fraser

G. Nugent D.M. Forsyth

R.B. Allen

Wapiti

C.N. Challies

G. Nugent

A.D.M. Latham G. Nugent

J.P. Parkes R. Sloan

Sika deer

M.M. Davidson

K.W. Fraser

G. Nugent C. Speedy

A.D.M. Latham

Sambar deer

M.J.W. Douglas

K.W. Fraser G. Nugent

G. Nugent

D.M. Forsyth

Rusa deer

M.J.W. Douglas

K.W. Fraser

R.B. Allen

D.M. Forsyth Continued

Acknowledgements

Species

Authors (1st edition, 1990)

Authors (2nd edition, 2005)

Authors (3rd edition, 2021)

Referees (3rd edition, 2021)

Chital deer

C.M. King

G. Nugent

D.M. Forsyth

A.R. Pople

Common fallow deer

M.M. Davidson G. Nugent

G. Nugent G.W. Asher

G. Nugent G.W. Asher

D.M. Forsyth

White-tailed deer

M.M. Davidson C.N. Challies

G. Nugent

G. Nugent

A.D.M. Latham

Moose

M.M. Davidson K.G. Tustin

K.G. Tustin

K.G. Tustin

D.M. Forsyth

The editors sincerely thank all the authors and referees, especially those authors who wrote for more than one edition, and those who were authors previously and referees later. The total number of authors contributing to the first edition was 30, the second edition 29, and the third edition 37. Nine authors worked on all three editions: G.R. Clark, P.E. Cowan, J.E.C. Flux, J.G. Innes, C.M. King, J.C. McIlroy, E.C. Murphy, K.G. Tustin and B. ­Warburton. Two previous authors (M.R. Rudge and R.H. Taylor) later contributed as referees. New perspectives have been added to the third edition by 15 new contributors: R.B.  Allen, K.M. Borkin, E.Z. Cameron, B.L. Chilvers, J.A.  Duckworth, P.M. Garvey, A.S. Glen, K. Greig, A.D.M.  Latham, H.W. Nathan, J.C. Russell, C. Speedy, J.M. Wilmshurst, Y.M. van Heezik and A.J. Veale. A total of 24 previous authors not directly involved in the present edition have nevertheless graciously given permission for the current updates to be based largely on their first or second edition texts. Both editors worked on the Editors’ introduction, but the chapters were managed separately: Chapters 1–6 plus 9–10 by C.M. King, and Chapters 7–8 plus 11–14 by D.M. Forsyth. For the use of copyright information presented as illustrations, we thank both the owners of the copyrights who gave us permissions and the artists who prepared the images, as named in the captions. A very special editorial ‘thank you’ to Priscilla Barrett for her colour paintings; to J.C. Russell, Zach Carter, and J.P. Parkes for compiling and checking the tables of island distributions; to all the authors for checking their own and other chapters several times and responding to calls for help, often at short notice; to M. Oulton, for updating the maps in Figs 0.1, 5.1 and 7.4, and for producing Plates 15 and 16; to J. Frith (Flat Earth Mapping, Adelaide) for drawing the maps in Figs 7.1, 7.2,

7.3, 12.1, 13.1, 13.2, 13.3, 14.4, 14.5, 14.8, 14.9, 14.10, 14.11, 14.12 and 14.14; to M.C. Latham for drawing the map in Fig. 14.7; to Sabrina Malcolm for drawing Fig. 6.1; and to A.J. Veale for redrawing Figs 6.2, 6.4 and 14.1. At Oxford University Press (Auckland), J. Olson, A. French, N. Jackson, H. Allan, and J. Rawnsley, assisted by the late C.T. Duval, supported the first edition throughout its lengthy gestation. H. Fawcett, T. Campbell, E. ­Filleul (Melbourne) did the same for the second edition; at CSIRO Publishing (Melbourne), L. Webb and T. Kudis did the same for the third. J. Window (Living Language, Lismore) and J. Birtles (Organic Editing, Melbourne) assisted with editing of chapters in the third edition. We all gratefully acknowledge financial assistance for the first edition from the Lottery Board, the John Ilott Charitable Trust, the Ministry of Agriculture and Fisheries, and the Department of Scientific and Industrial Research, and for the second edition from the Royal Society of New Zealand, Department of Conservation, Manaaki Whenua – Landcare Research, Australasian Wildlife Management Society, the Environment and ­Heritage Committee of the New Zealand Lottery Grants Board, and a consortium of regional councils led by Environment Waikato. Finally, the third edition would not have been possible without the long-term support of the two editors’ employers: the University of Waikato and NSW Department of Primary Industries, Orange, Australia.

xiii

Editors’ introduction THE UNIQUE NEW ZEALAND MAMMAL FAUNA The study of mammals in New Zealand is a different science from that of most other countries. Not only is the natural environment of the New Zealand region strongly dynamic, but also the history of its fauna, and of its very recent establishment by humans from Polynesia and Europe, is unique for three reasons. First, the New Zealand mammal fauna is an artificial mixture of native and introduced species. That is not in itself unusual, since few mammal faunas do not include some non-native species, but in New Zealand the established introduced species vastly outnumber the native species. The few native land-breeding mammals we have (only bats and pinnipeds) are rightly celebrated, and our knowledge of them has rapidly expanded in recent decades. Second, this unusual mixture includes species that evolved in a wide range of habitats, and were brought from both temperate and tropical climates, and many of them had never met before. Those that have established themselves have adapted in interesting ways to living in a novel environment, and with other, unfamiliar species. Third, the islands of New Zealand were free of all living four-footed mammals until a few centuries ago. The arrival of large numbers of introduced species altered the native biota, especially the birds, lizards and invertebrates, and the environment in which they evolved. Furthermore, both the native and the introduced mammals of New  ­Zealand have had a short but turbulent history of exploitation, in successive, separate waves and using different techniques, by two distinct groups of human settlers. The circumstances of these events are unique in detail, though not in principle, and are paralleled to lesser extents on other remote islands such as Mauritius, Canary Is or Hawaii. They make the ecology, behaviour, interactions, and population dynamics of mammals in New Zealand, both native and introduced, of particular interest to mammalogists everywhere.

GEOGRAPHICAL BACKGROUND The New Zealand region comprises a large archipelago of temperate islands and their surrounding continental shelf, plus the Ross Dependency in Antarctica (Fig. 0.1). The North and South islands, together known as ‘the mainland’, measure 114  453 km2 and 150  718  km2,

respectively. The largest of the other islands, Stewart I./ Rakiura (included by some authors in the phrase ‘the three main islands’) is 1746  km2. The Chathams group totals 963  km2, and all the other islands, from the subtropical Kermadecs to the subantarctic Auckland and Campbell groups, total 824  km2. The grand total is 268 704 km2, spread over an enormous area of the southwestern Pacific Ocean from 33°S to 53°S latitude and from 162°E to 173°W longitude (Plates 15 and 16). The Ross Dependency is also part of the New Zealand region, and is defined as the segment of the Antarctic south of 60°S and from 160°E to 150°W, a triangular area of ~414 400 km2 mostly of sea but also including nearly the whole of the Ross Ice Shelf. The main islands sit astride an important tectonic boundary, and have been shaped by the active geological processes that can still be observed today, including volcanism, large earthquakes accompanied by extensive horizontal and vertical earth movements, glaciation and rapid erosion.37 The islands are elongated, and most inland locations are 100 km2 area, of which the largest is Lake Taupo (606 km2). The climate is temperate with prevailing westerly winds, but the complex topography produces great local variation. Rainfall ranges from 10 000 mm/year in some high-­elevation basins in the Southern Alps. Mean annual sea level temperatures range from 10°C (50°F) in the south to 16°C (61°F) in the north. The distribution of natural vegetation cover, and the historical changes in it, are summarised in Table 0.1 and Plate 16. The various types of native forest (mostly mixed podocarps/hardwoods on the lowlands, southern beech on the mountains) are all evergreen. In lowland and northern districts the growing season is long and grass may grow all the year round.

HISTORICAL BACKGROUND In the late Cretaceous period, ~83 million years ago (mya), the fragment of continental crust that later became the New Zealand archipelago split off from the side of Gondwanaland, the ancient southern landmass, and

Editors’ introduction

Figure 0.1:  Left: The New Zealand region, extending from the Kermadec Is (30°S) to Campbell I. (52°S). Macquarie I., Lord Howe I. and Norfolk I., administered from Australia, are excluded. (1) Kermadec Is; (2) Chatham Is; (3) Bounty Is; (4) Antipodes Is; (5) The Snares; (6) Auckland Is; (7) Campbell Is. Right: Ross Dependency, New Zealand’s section of Antarctica. Stippled area: Ross Ice Shelf. (Maps drawn by M. Oulton.)

Table 0.1.  Vegetation cover of New Zealand in pre-Polynesian, early European and modern times. See Plates 15 and 16.

Pre-Polynesian

Natural forest Alpine zone Open

countryb

2010d

1840

Area, km2

%a

Area, km2

%

Area, km2

%

~21 102

78

~14 000

53

8101.9

30

3725

14

3725

14

3725

14

~1225

5

7744

29

10 843.5

40

Lakesc

324

1

324

1

529.6

2

Riverbeds

150

0.6

150

0.6

Swamps

~230

0.9

455

2

114.5

5-year class. Predators, parasites and diseases Dama wallabies have few predators in New Zealand except dogs. The parasites and diseases of wallabies in New Z ­ ealand are little known. A sample of eight dama from the Rotorua district found no trace of ecto- or endoparasitic infection,7 but damas on Kawau I. have tested positive for

1 – Family Macropodidae

Yersinia enterocolitica, a bacterium that can cause zoonotic infections in a wide variety of vertebrate taxa.18 None of 98 dama shot at Lake Okataina Scenic Reserve had any macroscopic lesions in the spleen or liver that would indicate infection with tuberculosis,47 and there are no reports of any captive tuberculous dama wallabies elsewhere in New Zealand, so their role as vectors of tuberculosis is probably negligible. Adaptation to New Zealand conditions Damas have adapted well to New Zealand. They have retained their usual patterns of behaviour, seasonal breeding, maturation, and growth. Numbers of dama in Australia have been greatly reduced by habitat clearance and predation, but in the Rotorua district they are plentiful and their population is still expanding. Although damas can survive within indigenous forest, they have done much better (in terms of age at sexual maturity, bodyweight and kidney fat reserves) in areas comprising both forest for cover and pasture for food. Significance to the New Zealand environment Damage. For many years the Rotorua damas have been considered as potential pastoral pests, but so far there have been no reports of major damage to agriculture. Based on daily dry matter forage consumption, ~10 dama wallabies are equivalent to one ewe consuming 550 kg of dry matter per year.41 Similarly, dama only occasionally browse new plantings of Pinus radiata. Of far greater importance are the effects of damas on indigenous vegetation. An early vegetation survey in the Lake Okataina Scenic Reserve showed that regeneration of the most palatable species, such as hangehange (Geniostoma rupestre crassa), Fuchsia excorticata, raurekau (Coprosma grandifolia), karamu (Coprosma robusta), patē (Schefflera digitata) and five-finger (Pseudopanax arboreus), was inhibited in sites accessible to wallabies.38 Unpalatable species such as mangeo (Litsea calicaris) and rewarewa (Knightia excelsa) were common in the understorey. Measurements of vegetation response in exclosures established in 1984 confirmed that, where both red deer (Cervus elaphus) and wallabies had been excluded, plant species diversity had increased by 142%, and where only wallabies were excluded, biodiversity had increased by 57%.97 Therefore, the regeneration of the most palatable plant species would require the removal or reduction to low densities of both deer and damas.6,110

Uncontrolled dama populations are as capable of c­ hanging the pattern of forest succession, or at least altering the local abundance of different species, as are deer and possums elsewhere. A 2016 report estimated that the annual cost of the impacts caused by dama to agriculture and the environment might be as high as NZ$4 million.40 On Kawau I. only remnant patches of the once-diverse native forest remains, and these are mostly devoid of palatable understorey species.98 Dama, along with possums and other wallaby species, limit the regeneration of forest species on Kawau, and in the longer term will have severe repercussions on the persistence of the existing forest cover90 if not removed. Control. Serious attempts to control damas in the Rotorua district started in 1962–63 with eight aerial 1080 operations covering all land tenures, but their effectiveness was not assessed.98 For the next 20–25 years, control was restricted to rateable land and carried out by the local pest destruction board, usually by spotlight shooting and with occasional use of 1080 poison. In 1987 and 1988, the Department of Conservation (DOC) carried out two aerial operations targeting dama wallabies using standard possum baits (Mapua cereal pellets) coated with 0.15% 1080, sown at a rate of 6 kg/ha.53 Both operations killed >90% of the wallabies.1 In contrast, free-ranging dama were never seen to eat Mapua pellets when also offered carrot baits.47 Warburton99 trialled 1080 poison in Carbopol ® gel spread onto the foliage of a stem of broadleaf placed upright in the ground. From faecal pellet counts, he estimated that this trial achieved a kill of 87%, at a cost of NZ$8.50/ha in 1990, considerably cheaper than most aerial operations (at least NZ$11.90/ha) at that time. Williams103 trialled bait stations, but found that wallabies were displaced from them by the more numerous and aggressive possums. Driven by increasing public concern about use of 1080, potential alternative toxicants were reviewed by Morriss et al.69 They recommended testing Feratox® (encapsulated cyanide), and this product was subsequently registered for dama.80 A third suggestion, Feracol ® (cholecalciferol paste), was later found to be unpalatable to damas.68 The three regional councils (RCs) that have dama wallabies on their lands have included them in their ­ regional pest management plans (RPMPs). Bay of Plenty RC’s plan for 2011–16 aimed to contain wallabies within a defined area.5 Waikato RC’s long-term objective in their 2014–24 RPMP is eradication of wallabies.96 Auckland RC’s 2007–12 RPMS objectives were first, to confine

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wallabies to Kawau I. and, second, to eradicate wallabies from the whole region within the life of the strategy.3 In 2006, an agreement by multiple agencies (Bay of Plenty RC, Waikato RC and DOC) resulted in a draft proposal aiming to eradicate dama from the mainland by 2050, and detailed the advocacy, management and research needs required to achieve that aim. The proposal was revised in 2016,2 and the objective changed from eradication to preventing the further spread of dama wallabies outside defined containment areas, and then progressively removing them from inside. On Kawau I. control work stopped in 1973 when farming was abandoned. In 1992 the Pohutakawa Trust (a Community Initiative Programme) was established and, in collaboration with DOC and Auckland RC, aimed to eradicate dama, along with the other three species of wallabies found on the island, by 2005.102 The trust manages the eradication program, with technical support from DOC and Auckland RC. Initial control efforts, by shooting and using bait stations to deliver pival (an anticoagulant bait) and brodifacoum, were concentrated in the north of the island, and ~3000 wallabies were killed annually. This program did not eradicate wallabies from the island, in part because not all islanders agreed with it, but sustained control efforts continue; ~800 wallabies were killed in 2014/15.27 The population is thought to have been greatly reduced because of this control. In Australia, dama wallabies are a resource rather than a pest, and therefore their conservation is a priority. The ancestors of the New Zealand stock came from the South Australian population of the eastern nominate, which was subsequently extirpated from the Australian mainland. Initial genetic studies indicated that the Kawau I. population may have originated from the Australian mainland, thus preserving this genetic lineage from extinction.89 Accordingly, the population in New ­Zealand was deemed suitable for reintroduction. DOC permitted capture, conveyance, and holding permits for farming of up to 100 wallabies, plus export to a range of countries, including Australia. Late in 2003, 60 dama wallabies were live-­ captured on Kawau I. and relocated to a zoological park near Adelaide for quarantine, and from there they were subsequently reintroduced into Innes National Park, South Australia.23 However, recent genetic work shows that the Kawau I. population originated from the extant dama population on Kangaroo I. (South Australia);24 therefore the New Zealand translocation, while useful as a source of

individuals, has not preserved mainland ­Australian dama genetic diversity.

BENNETT’S WALLABY Notamacropus rufogriseus rufogriseus (Desmarest, 1817) Synonyms Kangurus rufogriseus Desmarest, 1817; ­Wallabia rufogrisea rufogrisea (Desmarest, 1817); M ­ acropus (Halmaturus) fruticus Ogilby, 1838; Wallabia ­rufogrisea fruitica (Ogilby, 1838); Macropus rufogriseus rufogriseus (Desmarest, 1817). Also called red-necked, brush, or scrub wallaby. Description Distinguishing marks – see Table 1.1. Bennett’s is the largest wallaby in New Zealand, standing some 800 mm tall and frequently weighing over 15 kg (males of up to 26.8 kg have been recorded).23 It has relatively long, dense fur, rufous-coloured (of variable colour intensity) over the shoulders and greyish-brown on the rest of the body, and shorter pale grey fur on the chest and belly. It is an alert animal, and when disturbed does not often stop until it has travelled out of sight. It uses all available cover for refuge, and constantly scans for danger with its acute hearing and sight. Chromosome number 2n = 16. Dental formula I 3⁄1 C 0⁄0 Pm 1⁄1 M 4⁄4 = 28. Field sign The faecal pellets (~25 mm × 15 mm in adults) are generally a flattened square shape, but can often be more elongated and rounder. Game trails created by Bennett’s wallabies can be seen leading into tunnels under dense thickets of scrub and flax (Phormium tenax). In sandy or muddy substrate, their distinctive footprints, with a long middle toe and a smaller toe either side, may be visible. Their grazing and browsing cannot be easily differentiated from that of sheep, which share their habitat. Measurements See Table 1.4. History of colonisation In 1870, a Captain Thomson brought several Bennett’s wallabies from Tasmania to Christchurch,91 and in 1874 two females and a male, probably from this stock, were liberated on the eastern Hunters Hills, near Waimate,

9 – 690 (620–780)

Canterbury.85 Genetic analysis suggests that the founder population probably included >3 animals but 3 years old. b. All ages.

Australia

14 (11–15.5) 14 F

–

710 (660–740)

105 200 620 10.5 (6.8–13.6) 12b Canterbury

F

–

610

9

10

–

200–210 –

770 (690–860)

–

780 (710–920) –

10–12 F

1275 ± 17

19.7 (15–26.8) –

147a

M Australia

Canterbury

105 220 620 13.2 (6.8–22.7) M Canterbury

10b

–

650

10 200–230 12–21 198a Canterbury

M

1435 ± 23

–

–

Reference Head and body length (mm) Total body length (mm) Body wt (kg) Sample size Sex

Table 1.4:  Body measurements of Bennett’s wallabies in Canterbury, New Zealand, and in Australia (mean ± s.d.).

Tail length (mm)

Hind foot length (mm)

1 – Family Macropodidae

Habitat Bennett’s wallaby is an ‘edge’ species, requiring cover for shelter and access to grasslands on which to feed.10,100 The mountain ranges it occupies reach 2000 m or more

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The Handbook of New Zealand Mammals

Figure 1.2:  Historical and current distribution and confirmed sightings and kills (from 2000–2016) of Bennett’s wallabies in Canterbury and Otago.40 The cross hatched areas represent lakes.

above sea level, covered with tall tussock (dominated by Chionochloa rigida) and dissected by steep gullies. The valleys on the eastern side of the Hunters Hills support remnants of a once-widespread podocarp forest, now dominated by broadleaf, māhoe (Melicytus ramiflorus), marble leaf (Carpodetus serratus) and fuchsia (Fuchsia

excorticata), with occasional tōtara (Podocarpus hallii) and mataī (Prumnopitys taxifolia). The margins of these forests are frequently bordered by areas of flax, Coprosma spp. and matagouri (Discaria toumatou), with intertwining bush lawyer (Rubus spp.) and Muehlenbeckia spp. Further west, many gullies support matagouri and

1 – Family Macropodidae

Coprosma species.100 High production exotic grasslands, such as dairy pastures, are avoided, probably because suitable cover is scarce.40

browntop, cocksfoot and bluegrass were found more often in the diet than in the pasture, suggesting that the wallabies were selecting these species, although McLeod63 considered Bennett’s wallaby to be a nonselective grazer. Bennett’s wallabies in the Hunters Hills fed on the same plants and in the same areas as sheep, but at different times (wallabies at night and sheep during the day). Celmisia spectabilis was an exception – wallabies browsed this species, extracting the soft leaf bases and discarding the coarser leaf blades,10 whereas sheep avoided it.

Food Diet. Bennett’s wallaby is primarily a grazer, but also browses palatable tree and shrub species, particularly in higher elevation areas. In the Hunters Hills area, ~25 ­species of grasses and herbs made the largest contributions to the diet.63 The relative proportions of each species in the diet changed slightly between seasons, but not significantly: hawksweed (Hieracium spp.) was the favourite in all seasons, and clover was particularly relished in spring (Table 1.5). Grasses such as Yorkshire fog,

Feeding behaviour. Wallabies move to feeding areas along well-defined trails leading from daytime cover to

Table 1.5:  Foods of Bennett’s wallabies in Canterbury.63 Data listed in descending order of percentage frequency of occurrence of the 20 most commonly eaten species by season.

Winter 1984 species

Spring 1984 %

Hieracium

spp.b

species

Summer 1984–85 %

species

Autumn 1985 %

species

%

13.33

Hieracium spp.

16.66

Hieracium spp.

9.60

Hieracium spp.

11.00

Holcus lanatusa

7.53

Trifolium spp.

9.06

Dactylus glomerata

8.40

A. scabrum

9.26

Agropyrona

6.83

A. scabrum

7.30

A. scabrum

7.93

Anthoxanthum odoratum

8.43

Dactylisa glomerata

6.03

H. lanatus

6.80

A. odoratum

7.46

D. glomerata

8.26

Anthoxanthuma odoratum

6.00

A. odoratum

6.60

Carex spp.

6.96

H. lanatus

6.66

Blechnum spp.d

5.56

Festuca novae-zealandiae

5.90

F. novae-zealandiae

6.56

Coprosma rugosa

5.92

4.76

Carex spp.

5.10

Trifolium spp.

5.66

F. novae-zealandiae

5.83

Cyathodes Carex

scabrum

colensoic

spp.a

4.60

V. australis

5.00

A. tenuis

5.20

Carex spp

5.33

Festuca novae-zealandiaea

4.33

Cyathodes colensoi

4.30

Coprosma spp.

4.80

Moss species

4.23

Geranium sessiliflorum b

4.26

D. glomerata

4.20

Cerastium holosteoides

4.10

Coprosma spp.

4.06

Moss species

4.10

C. holosteoides

3.76

Moss species

4.06

A. tenuis

3.80

Vittadinia australisb

3.63

Coprosma spp.

2.90

Celmisia spp.

3.23

C. colensoi

2.93

3.36

Moss species

2.83

H. lanatus

2.90

Rumex spp.

2.93

3.20

Celmisia spp.

2.40

Rumex spp.

2.80

Festuca rubra

2.86

Cerastium Trifolium Rumex

holosteoidesb

spp.b

spp.b

Brachycome sinclairii b Coprosma Celmisia

spp.c

spp.b

Hypochaeris

radicata b

Gaultheria antipodac a. Grass. b. Herb. c. Tree or shrub. d. Fern.

3.16

Agrostis

tenuisa

2.33

Coprosma

2.76

Blechnum spp.

2.23

F. rubraa

rugosac

capillarisb

2.36

C. holosteoides

2.53

2.26

V. australis

2.13

1.90

Trifolium spp.

2.10

2.46

G. sessiliflorum

2.10

Crepis

2.23

Rumex spp.

1.86

Blechnum spp.

1.90

Celmisia spp

2.10

1.90

Gaultheria antipoda

1.76

G. sessiliflorum

1.73

G. sessiliflorum

1.23

1.70

B. sinclairii

1.30

C. colensoi

1.63

Poa laevisa

1.13

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open grass areas. When feeding on grass, they crouch and move their heads in an arc. When browsing on shrubs, the forepaws are used to manipulate food, and females often hand leaves to their pouch young at foot.63 They may scratch and dig with the forepaws to reach edible roots. Like other macropodids, Bennett’s wallabies occasionally pause during feeding to engage in merycism: a violent convulsive action of the abdomen that serves to regurgitate a bolus of food that they then chew and reingest. They drink occasionally, especially in drier months. Social organisation and behaviour Activity. Bennett’s wallabies are nocturnal to crepuscular, moderately gregarious animals. They keep under cover during the day and feed in the open at night, but remain under or close to cover in wet conditions.63 Home range. Marked individuals observed by McLeod63 moved 1–3 km in a night, though seldom further than 150–180 m from the bush edge; they also made occasional sorties of up to 2–3 km to feed on seasonally available swede crops. When chased by dogs they usually doubled back, presumably on reaching their home range boundary.10 Their foraging ranges overlap those of domestic sheep, which use the same areas but at different times. During the day, wallabies retreat to the lower slopes and bush to find cover, while the sheep feed on the middle slopes. In late afternoon and evening, sheep move up to higher elevations and the wallabies emerge to feed on the middle slopes.63 Dens. Bennett’s wallabies use both rest and den sites, which are usually not shared or defended. Rest sites found by McLeod63 were on grass clearings in the bush or among tussock or flax at higher elevations, and were used during the day, more by males than by females. Dens were in more secluded places, often under thick undergrowth or logs, with a depression often covered with leaves and moss, and they were used more often by females. Communication. Individuals within a population often have limited contact with one another and therefore a low incidence of agonistic behaviours.63 Individuals identify one another by smell and, with the exception of females and their young, this is most noticeable during the breeding season. Although often seen alone, they still react to alarm with the typical macropod thumping of the hind feet.

Threat behaviour is simple: the aggressor stands erect with ears pricked, chest expanded and forepaws crossed. In a fight, each animal holds the other in a head lock and attacks by biting, punching, kicking and fur pulling.63 Submission is signalled when one partner turns its head and upper torso away from its opponent, if necessary augmenting the signal with ear quivering and tail swinging. The dominant individual usually chases the other off for 20–30 m. Reproductive behaviour. During the breeding season, several males will follow each oestrous female and fight between themselves for possession of her (15% of interactions observed in the breeding season and 1.5% of interactions out of the breeding season, were of fighting over females). The successful male will approach the female and sniff her pouch and cloaca, urinating and exhibiting flehman (lip-curl).23 The male may hold and cuff the female about the head. If she is receptive she crouches and raises her tail, enabling the male to mount her. After mating, both sexes groom or graze together, and then will attempt to mate again after 5–15 min. If the female is not receptive she will move away as the male approaches, and often coughs and hisses at him.63 Comparatively large testes relative to body size suggests sperm competition among males.23 Reproduction and development Males in the Hunters Hills were sexually mature by 21–22 months, some as young as 16 months. All females were mature by 23–24 months; some showed eversion of nipples from as early as 14 months, but the young of these early maturing females often died.11 Seasonal variations in the weight of the prostate gland are a useful indicator of male reproductive capacity. The peak of the breeding season is in February and March, declining from April to July; from then until the following February, the prostate glands are at minimum size.11 Fertilisation at the post-partum oestrus produces a quiescent blastocyst delayed by the suckling pouch young. The complete gestation of a blastocyst within the breeding season takes ~26 days, but after June the blastocysts remain delayed by a seasonal diapause until the following breeding season.65 Most young are born in February and March, then progressively fewer each month from April to July. In the population studied by Catt,10 age-specific birth rates were estimated at 0.947 births per year in females >2 years old, and 0.581 in those aged 2–3/ha down to almost zero, especially after successful control operations. Methods of assessing relative abundance in the Hunters Hills have been compared.101 A simple visual method (the Guildford Score) is now used by Environment Canterbury staff, and includes a visual assessment of faecal pellet abundance, tracks, and wallaby sightings. The results from this qualitative method were consistent and correlated well with more laborious and costly quantitative methods for estimating relative abundance, including counts of wallabies from the air and of pellets on transects. Sex ratio, age and mortality. Sex ratio in pouch young is 1:1, but males predominate in shot samples of adults.11 Annual zonation in the periosteal zone of the mandible is a reliable indicator of age,12 but molar progression and cementum annuli are not. The frequency distribution of ages in a sample from a controlled population in the Hunters Hills in 1973 declined steeply to a maximum of 9  years. Juvenile mortality was low, increasing at 1 year and older. The mortality rate of male wallabies was independent of age, and the exponential birth rate was very high (0.347, probably near the maximum possible), largely as an artefact of official control.10 Predators, parasites and diseases There are no published records of predation on Bennett’s wallaby in New Zealand, although dogs can readily catch young or weak individuals. Among 240 wallabies sampled from the western Hunters Hills, nematodes comprised up to 20–30% of the stomach contents.63 Six species have been identified: Labiostrongylus communis, Globocephaloides trifidospicularis, Rugopharynx longbursarius, R. omega, R. australis

and Pararugopharynx protemnodontis.7,55 A spongy outgrowth of the lower jaw (lumpy jaw) may result from bruising or dental infection.10 Adaptation to New Zealand conditions Bennett’s wallabies have adapted well to the environment of the Hunters Hills, expanding both in range and in population numbers. They survive the sub-zero temperatures often found on shady, snow-covered slopes during the winter months. They have ready access to plentiful grazing and cover provided by indigenous bush, scrub areas, flax and matagouri, and tall Chionochloa tussock associations. In Australia, Bennett’s wallabies inhabit coastal shrubland and heath, and eucalypt forests with a moderate shrub component and access to open areas for grazing.9 Seasonal breeding, typical of the Tasmanian subspecies, has been retained in New Zealand, in contrast to the ­Australian mainland subspecies N. r. banksianus, which breeds year-round.9 Significance to the New Zealand environment Damage. Bennett’s wallaby was recognised as a pasture pest in the 1940s. Farmers reported them driving sheep off the pasture, fouling sheep feed, damaging fences, and destroying agricultural crops and exotic pine plantings.98 Based on daily dry matter forage consumption, ~4.2 ­Bennett’s wallabies are equivalent to one ewe consuming 550 kg of dry matter per year.41 No direct quantitative measure of damage is available except from within Waimate State Forest where, in 1978, apical buds and up to 20% of needles were removed from many Pinus radiata seedlings, and some seedlings were totally destroyed (seedling mortality ranged from 2–17% in the plots assessed).98 The damage was locally severe, but restricted to within 50–100 m of the forest edge. In many unfenced remnant patches of indigenous forest (e.g. in Matata and Mt Nimrod reserves, and Tasman Smith and Gunn and Hook Bush conservation areas), open to grazing by both wallabies and sheep, the understorey is severely depleted, and there is no regeneration of palatable species. A 2016 report40 estimated that the annual cost of their impacts on agriculture and environment might be as high as NZ$24 million. Control. From 1947 to 1956, the Department of Internal Affairs was responsible for controlling Bennett’s wallaby populations, and during this period ~70  000 wallabies were killed by government cullers, plus an estimated

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30 000 by private hunters.98 From 1971, the South Canterbury Wallaby Board (SCWB) employed hunters with dogs to shoot on average ~2500–3000 wallabies a year, equivalent to a sustained harvest of ~20% of the population.10 After November 1989, SCWB was replaced by Environment Canterbury; government subsidies that had applied to wallaby control ceased, and the full cost of control had to be met by the landholders. They chose to be responsible for their own wallaby control, so the wallaby control unit (formerly the SCWB) was disbanded in June 1992. The Biosecurity Act 1993 required EC to develop a regional pest management plan (RPMP), including an annual monitoring and inspection program to ensure landholders met their responsibilities. The primary aim of the RPMP was to prevent the spread of wallabies beyond their core range (~410 000 ha in the late 1990s), an area bounded by the Rangitata River in the north, the Waitaki River in the south, and Lake Tekapo and the Tekapo River in the west (Fig. 1.2). Within that area, landholders were required to keep wallabies below a Guilford Score of 4. At level 4, wallaby faecal and track sign are obvious and consistent; wallaby trails are well used; pellets are likely to be recorded on >60% of 80-cm plots; and there is a high probability of seeing wallabies in the area. However, containment within this area was not successful, partly because the culling level was insufficient to prevent natural spread, but also because of deliberate relocations.40 Aerial 1080 poison operations were first used against wallabies in 1960, and extensive reductions in numbers were achieved over the following few years. Use of 1080 poison on farmland creates practical difficulties, and, although 1080-impregnated cereal pellets are still registered for aerial and ground-based use on wallabies, it is used less frequently than are ground-based poisoning operations using alternative toxins and shooting. 1080 gel applied to palatable foliage is also registered for use on wallabies, and in a trial in the easily accessible Tasman Smith Scenic Reserve, Warburton99 achieved a 91% reduction in wallaby numbers, at a cost in 1990 of NZ$7.90/ha, compared with NZ$21.60/ha for aerial baiting from a helicopter. Feratox® (encapsulated cyanide pellets) has been registered for wallaby control and, although it is relatively expensive to use, it is a preferred method of removing wallabies because of the low risk to other species, especially livestock.75 Some landowners, especially those served with notices from EC, use contractors or recreational

hunters to carry out control, and many thousands of wallabies are shot annually. As Bennett’s wallaby has recently expanded from the containment area, EC are currently trialling methods for detecting and controlling low density populations typical of those in newly invaded areas. Choquenot and Warburton14 analysed 13 years of SCWB kill data, and developed a model of wallaby population growth in relation to density and prevailing rainfall. This model was then used to compare the cost-effectiveness of hunting with dogs, aerial poisoning, and 1080 gel applied to foliage. They concluded that where 1080 gel could be used, it should be the preferred option. In open tussock country, the model indicated that hunting with dogs every two years provides the most cost-effective control option, depending on the target density chosen. The model needs to be updated to include new toxins, like Feratox®, and detection methods, like thermal infrared imaging cameras and rifle scopes.

PARMA WALLABY Notamacropus parma (Waterhouse, 1846) Synonyms Macropus (Halmaturus) parma Waterhouse 1846; Thylogale parma (Waterhouse, 1846); Wallabia parma (Waterhouse, 1846); Protemnodon parma (Waterhouse, 1846); Macropus parma (Waterhouse, 1846). Also called white-throated or small brown wallaby. Description Distinguishing marks – see Table 1.1. The parma is the smallest member of the genus Notamacropus. It is uniformly light brown, with a light grey throat and chest and a white stripe on the cheek. The ears are short and rounded. When hopping the body is held low and the forepaws are tucked close to the chest. Parma wallabies do not often lie down, but rest by sitting with the tail between the legs.94 When alerted they stand with their forelimbs held close to the chest. They groom with their tongues, teeth, forepaws and the syndactyl toes of the hind feet. Females often clean the inside of the pouch whether or not pouch young are present.94 Chromosome number 2n = 16. Dental formula I 3⁄1 C 0⁄0 Pm 1⁄1 M 4⁄4 = 28. Field sign The faecal pellets are flattened, and square to rectangular,57 but cannot be distinguished from the pellets of dama wallabies.

59

95 133 ± 1

134 ± 2

408 ± 6

475 ± 26

–

4.0 ± 0.4

3.0 ± 0.1

486 ± 19

59 129 ± 1 441 ± 5 457 ± 5 3.5 ± 0.1

4.9 ± 0.4

142 ± 3 502 ± 26 498 ± 26

59

59

95 435 ± 4 – 3.3 ± 0.1

137 ± 1

483 ± 9 489 ± 6 4.6 ± 0.2

140 ± 1

Tail length (mm) Head and body length (mm) Body wt (kg)

Measurements See Table 1.6. Body size depends on the quality of the habitat. Females, especially, are significantly smaller where food is in short supply. History of colonisation Notamacropus parma was released on Kawau I. in ~1870 by Sir George Grey, along with other species of wallabies (Table 1.1). The taxonomic distinction between dama and parma wallabies on Kawau I., if known, was forgotten, although residents recognised two colour ‘phases’ of small wallabies on the island, calling one the ‘small brown’ and one the ‘silver-grey’. It was not until skins and skulls were examined in 1965 that parma were confirmed as being present on the island.106 At that time, N. parma was regarded as extinct in Australia, so in 1969 the International Union for the Conservation of Nature (IUCN) requested that N. parma be given protection on Kawau I. This was done by ministerial gazette, and all killing of N. parma was prohibited. From 1967 to 1975, 736 parmas were captured alive to establish breeding colonies throughout the world, but in 1972 Maynes57 confirmed that N. parma still lived in Australia. He mapped its distribution59 and showed that it was probably in no danger of extinction, so he recommended that no further Kawau I. individuals should be released into the wild in Australia. The parma was then removed from IUCN’s red data book, and in January 1984 protection of N. parma on Kawau I. was revoked.98 Distribution World. Notamacropus parma is patchily distributed in coastal ranges of east New South Wales from Gibraltar Range to north of Sydney. Within this range, it is generally scarce but locally common.59 After its rediscovery on Kawau I. many captive colonies of New Zealand-bred parma were established in overseas zoos.107 In Australia, parma currently have a conservation ranking of near threatened.109

F Australia

– F Kawau I.

7

F Kawau I.

31

M Australia

5

M

–

M

Kawau I.

24

New Zealand. Only on Kawau I. (Fig. 1.3).

Kawau I.

Sample size Sex

Table 1.6:  Body measurements of adult parma wallabies in New Zealand and Australia (mean ± s.d.).

Hind foot length (mm)

Reference

1 – Family Macropodidae

Habitat In Australia, parma are typically found in gullies of wet and, less often, dry sclerophyll forest with shrubby understorey.61 On Kawau I. parmas inhabit the tall kānuka and remnant taraire forests, preferably with a moist tree fern (Cyathea dealbata) understorey, and feed on the scattered grass clearings.94 They can also be found in the dense undergrowth of shrubs under exotic forests.

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Figure 1.3:  Distribution of wallaby species in the Hauraki Gulf. (Map drawn by C. Latham.)

Food Both parma and dama feed mainly on grass (60% of diet), but on Kawau I. parma also eat herbs including some that are avoided by the dama (Table 1.3). In one study, only Hypericum japonicum and Oxalis corniculata were eaten less than their availability in the pasture.95 Utilisation of such a wide variety of plant species by parmas might be due to over-grazing and browsing by wallabies on the island. On Kawau I., parmas usually feed alone, and often drink from pools and streams.94 Social organisation and behaviour Activity. The parma is predominantly nocturnal and secretive, remaining under dense cover during the day. It is primarily solitary and less aggressive than the dama, seldom making threats or fighting. Submissive behaviour

is signalled by crouching, lowering the head, nose sniffing and ear quivering.94 Alarm behaviour ranges from the standing posture, with attentive listening and looking in the direction of the disturbance, to thumping the hind limbs to alert other individuals. Thumping associated with fleeing results in a general exodus. Vocalisation is limited to hissing, in adults when threatening, and in pouch young when distressed. During interspecific encounters with damas, parmas were most often displaced, even by damas of smaller size.94 Den sites are usually under tall kānuka with an understorey of tree fern, often up to 200 m from the grassy feeding areas, and are rarely, if ever, shared. Reproduction and development Most females on Kawau I. first breed at 2–3 years old, but males at 1 year.58 The breeding season is long but variable,

1 – Family Macropodidae

so young may be born in any month of the year.56 In some years on Kawau I., the parma appears to breed almost year-round (e.g. 1970 and 1971); in other years (1972, 1973) only from March to July.58 M. Vujcich94 also observed long seasons in 1976 and 1977 (from February to August, except in May and June) and suggested that the later breeders were probably young females that had just reached puberty. The length of the oestrous cycle averages 41.8 days, and the gestation period, 34.5 days; pouch life is ~7 months.56 Population dynamics The sex ratio of adult parma wallabies on Kawau I. was not significantly different from parity in 199686 but that of the offspring of larger females tended (not significantly) to be biased towards males. Most animals in Maynes’58 sample were 1–2 years old, but one was estimated to be 9.5 and one 7.7 years. From a live-trapping study, Kinloch33 estimated a mean mortality rate of 0.31 per year, and a mean life expectancy (after 6 months) of 2.71 years, although it was unknown whether this population had been managed. Predators, parasites and diseases Parmas on Kawau I. have no predators except for infrequent attacks by domestic dogs. The only parasites recorded on Kawau I. are an unidentified ‘red/brown louse’94 and a species of nematode (Austrostrongylus sp.).18

has left little of the island remaining unaltered. In addition, the parma, plus three or four other wallaby species and the brushtail possum, have significantly curtailed the regeneration of the remaining indigenous forest, and eliminated hundreds of species still present on nearby wallaby-free Challenger I.25 Control. Parma wallabies on Kawau I. were shot and ­poisoned periodically from 1923 to 1969, especially in 1964–66,98 but protected between 1969 and 1984 (see above). In 1997 Auckland RC announced an intention to eradicate parma and the other wallaby species on Kawau I. over the long-term, via the eradication program organised by DOC and the Pohutukawa Trust (p. 21). However, some landowners do not want wallabies to be eradicated from Kawau I., and protect them on their properties.27 Consequently, eradication has not been feasible, and instead, parma and other wallabies are being managed in permissible areas using shooting and poison baits in bait stations.

BLACK-STRIPED WALLABY Notamacropus dorsalis (Gray, 1837) Synonyms Halmaturus dorsalis Gray, 1837; Wallabia dorsalis (Gray, 1837); Macropus dorsalis (Gray, 1837). Also called scrub wallaby. Description The black-striped wallaby is one of the common macropods of north-eastern Australia, but is seen infrequently because of its preference for forest and woodland with dense shrub understorey. Its light brown-grey fur and very distinctive dark dorsal stripe make it readily identifiable. It has a distinctive gait, characterised by a short hop with the body hunched and head held low.36

Adaptation to New Zealand conditions The optimal habitat of the parma in Australia appears to be wet sclerophyll forest with thick shrubby understorey and grassy patches, especially in gullies.60 In New ­Z ealand it has adapted well to pasture with adjoining cover, and its numbers on Kawau I. have increased dramatically. Parma females on Kawau I. have become significantly smaller than females from less dense populations in New South Wales (Table 1.6). They also breed for the first time later (at 2–3 years old) than female parma in New South Wales (1 year).58,59 Maynes suggests that the smaller size of Kawau I. parmas has become genetically fixed, as stock from Kawau I. raised elsewhere on surplus food still remain smaller than their Australian relatives.

Measurements The only known New Zealand specimen, a female with joey, weighed 12.7 kg, which is much heavier than the upper range (7.6 kg) reported for females in Australia. The head and body length was 720 mm, tail length 680 mm, hind foot 220 mm, ear 85 mm.105 The average weight of Australian males is 16 kg, females 6.5 kg.23

Significance to the New Zealand environment Damage. In the 1800s Kawau I. was covered with a diverse and luxuriant forest,8 but extensive clearing until 1973

History of colonisation The black-striped wallaby was common in the areas of Australia where Sir George Grey was collecting, and

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could easily have been represented among the several species of wallabies that he brought back to Kawau I. in ~1870. Nothing is known of its history there, and the few specimens recorded as N. dorsalis were misidentified.62,105 The only convincing record is of the female with joey, collected in 1954, and identified by R. Kean, of the New ­Zealand Forest Service. The skin and skull have been lost, but Kean showed a photograph and a record of the measurements to J.E.C. Flux during a Department of Scientific and Industrial Research Ecology Division investigation on the island. Flux knew Kean well, and affirms26 that he was a reliable and competent observer, who would not fail to notice that all other wallaby species on Kawau I. were quite different from N. dorsalis in size and pelage (Table 1.1). In Flux’s opinion, Kean’s identification was correct, in which case black-striped wallabies must have survived on Kawau I., seldom seen in their dense habitat, for >80 years. However, the comparatively large head–body measurements and weight of this female specimen, relative to Australian females, were unusual. Distribution World. Eastern Queensland and north-eastern New South Wales.36 New Zealand (Fig. 1.3). Kawau I. only, from ~1870 to ~ mid-20th century, now presumed extinct there. Nothing is known of the biology of this species in New Zealand. Flux 26 suggests that the reason the black-striped wallaby disappeared after so long is that it was a large animal that would be more vulnerable to, or selected by, the hunters working on wallaby control on the island from the 1920s. The alternative explanation, that it was never there, cannot be ruled out on present evidence.

Genus PETROGALE There are 17 species of Petrogale, the rock-wallabies, with much variation in size and colouration.54 Some members of the genus are brightly coloured, more so than wallabies from other genera, whereas other Petrogale species are dull grey or brown. The tails of some species are bushy along their entire length, but others have only a terminal ‘brush’. All species have tails that are less tapered than wallabies from other genera. When moving, the tail is held up off the ground with the tip higher than the animal’s back, creating a U-shape. The feet are shorter and

broader, with reduced claws, compared with other macropods, and the soles of the hind feet have a fringe of stiff hairs.81 Suckling young that have left the pouch are often left in a safe location while the mother feeds, which presumably decreases the extent to which a young animal has to traverse difficult terrain.

BRUSH-TAILED ROCK-WALLABY Petrogale penicillata (Gray, 1827) Synonym Kangurus penicillatus Gray, 1827. Description Distinguishing marks – see Table 1.1. Petrogale penicillata is the only rock-wallaby in New  ­Zealand, and its terminally brushy tail and rufous coloured rump make it quite distinct from all the Notamacropus species and the swamp wallaby. It is bluish grey above, rufous on the rump and belly, and has whitish patches on the forehead and cheeks. It usually moves with short jumps, in an apparently erratic course. The tail serves as a rudder and counterbalance, but is not used to support the body, as in other Macropodidae. Trees are frequently accessed by climbing, or bouncing off a series of low branches or rocks.4 Chromosome number 2n = 22. Dental formula 13⁄1 C 0⁄0 Pm 1⁄1 M 4⁄4 = 28. Field sign Faecal pellets are round, pear-shaped, or cylindrical with a pointed end, but due to variability in pellet shape, they are not easily distinguished from the other wallabies found on Kawau I. Well-defined trails may be found leading to den sites on cliff faces. Measurements See Table 1.7. History of colonisation An unknown but probably small number of brush-tailed rock-wallabies were introduced from central New South Wales, Australia, to New Zealand and released on Kawau I. by Sir George Grey ~1870.21 Others were subsequently liberated on Motutapu I. by J. Reid in 1873,91 and quickly spread across the causeway to Rangitoto I., where they reached high numbers by 1912.98 Some specimens from Motutapu I. may also have been translocated back to Kawau I.

4

22

–

New Zealand (Fig. 1.3). Brush-tailed rock-wallabies have been eradicated from Rangitoto and Motutapu islands, but still survive on Kawau I.

– 540 (520–580)

Habitat The favoured habitats of rock-wallabies on Kawau I. are the cliff faces and steeper areas still vegetated with pohutukawa (Metrosideros excelsa), puriri and taraire. They have also used the pine forests near Bon Accord Harbour.

a. Composite sample from Kawau I. (n = 8) and Rangitoto I. (n = 5).

– – Australia (adults)

7.5

– 17 F (adults)

5.7 ± 0.8

Distribution World. Petrogale penicillata is patchily distributed on the east side of the Great Dividing Range from southern Queensland to southern New South Wales. Small isolated populations persist west of the Great Dividing Range and in east Victoria. Their numbers have declined significantly since the early 1900s when many were shot for skins or bounties.22 More recently, competition from goats and rabbits and predation by foxes have further reduced their numbers, and they are classified as ‘Vulnerable’ by IUCN. Petrogale penicillata, probably from south-east Queensland, are also found in parts of Oahu I., Hawaii, after escaping from captivity shortly after 1916.20,92

610 (560–670)

4 –

–

105 140

– –

520 4.3 (2.8–5.6) 6

13

F

M

(all ages)

Motutapu I. ± s.d.

6.7 ± 0.9

470

105 140 470 7 Hauraki Gulfa

M

4.8 (3.0–5.8)

530

Reference Hind foot length (mm) Tail length (mm) Head and body (mm) Body wt (kg) Sample size Sex

Table 1.7:  Body measurements of brush-tailed rock-wallabies in New Zealand and Australia.

1 – Family Macropodidae

Food Petrogale penicillata is classified as a grazer/browser on a broad mix of plants.45 From faecal and stomach content analysis and observations on grazed vegetation, Szymanik87 concluded that rock-wallabies on Rangitoto I. fed selectively, especially on pohutukawa and rātā (Metrosideros spp.), Coprosma spp. and several types of grasses. Other species regularly eaten included Griselinia lucida, Astelia banksii and Blechnum capense. Occasionally Cythodes spp., Geniostoma ligustrifolia, Pteridium aquilinum and Pseudopanax arboreus were also eaten. Carcasses examined had a lower level of fat than recorded in similar wallaby necropsy studies, suggesting that the lack of grasses on the bare scoria fields of Rangitoto I. was a serious deficit for the wallabies. Bad weather often inhibited movement across the causeway to pastures on Motutapu I., implying that when Rangitoto wallabies were forced to browse rather than graze, they were not getting adequate nutrients from the available shrubs. Social organisation and behaviour Activity. In Australia, rock-wallabies are largely nocturnal in summer and crepuscular or partially diurnal in

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other months. On Rangitoto I. they were almost totally nocturnal.87 On Motutapu I. most rock-wallabies fed during the night on pasture, and then retreated soon after sunrise to the protection of the cliffs. They climbed trees to browse, explore, groom, sun themselves or sleep. They then returned along well-marked paths to graze on the pasture around sunset.4 Home ranges. On Motutapu I., rock-wallabies were gregarious, with a defined social hierarchy.4 Their annual or seasonal home-range sizes in New Zealand are unknown. Foraging ranges measured on Motutapu I. in 1978–79 were ~0.58 ha and 0.38 ha in male and female adults, respectively; sorties seldom exceeded 150 m. On Rangitoto I., foraging ranges were much larger and sorties longer, including trips across the causeway to feed on Motutapu I.87 Dens. The social hierarchy is well enforced around resting and den sites, which are probably a limiting resource. Although two females, or a mother and her young, sometimes share shelters, males never do and typically avoid one another. Rest sites are used for sunning, grooming and sleeping, and these are usually at the base of a rock or on the branch of a tree.4 Dens are more enclosed than rest sites, have more than one entrance, and provide more shelter. Many dens are excavated under the roots of pohutukawa growing on the cliffs. Communication. In intraspecific encounters, each animal sniffs the snout of the other, and presumably can thereby identify the other individuals of the group. Vocalisations are restricted to hissing, e.g. in juveniles separated from their mothers, in chased individuals, and in females when rebuffing males during attempted copulation.4 In agonistic encounters the opponents face each other, pull grass, strike out with the forepaws, and eventually may chase or occasionally fight. In a fight each attempts to pull the fur and bite the neck and head of the other, and to rake the chest and stomach with the hind claws. Fights may be avoided by submissive behaviour, i.e. averting the face or body away from the aggressor. When alarmed, rock-wallabies thump the ground with the hind feet and flee, alerting other wallabies in the area to the danger.4 Reproductive behaviour. The breeding system appears to be polygynous. Males attempt to mate with multiple

females, whereas females usually show serial mate fidelity. Batchelor4 recognised five sexual behaviours, not all observed at every encounter: (1) The male sniffs the female’s cloaca, while she usually remains motionless; (2) he follows her about, while keeping subordinate males away; (3) he forces her head on to his sternal gland or genitalia; (4) in the ‘mating bow’, he sniffs her cloaca, then stands upright with head and forepaws pointing upwards, and often with penis everted; and (5) copulation, each attempt rarely exceeding 5–10 s. The receptive period of oestrous females is only 3–12 h, so the males constantly check the females’ reproductive condition. Dominant males tend to gain the highest number of successful matings, and males 20 years, so DOC is confident that they have been eradicated from Rangitoto and Motutapu islands. On Kawau I. rock-wallabies were shot and poisoned from 1923 until 1973. Between 1967 and 1975, 210 rockwallabies were live-captured for transfer to zoos.98 Some individuals have also been live-captured and relocated to Australia. This repatriation program was carried out by the Waterfall Springs Conservation Association, a private organisation, and the wallabies are now kept at Waterfall Springs, NSW, as part of a captive-breeding program. Auckland RC aims to confine the last population of rock-wallabies to Kawau I., and eventually to eradicate all wallabies from the region, although the control program organised by DOC and the Pohutukawa Trust (p. 17) currently focuses on parma, dama and swamp wallabies.

Significance to the New Zealand environment Damage. On Motutapu I. the rock-wallaby was considered a pest because it competed with stock for pasture and accelerated erosion of the cliffs by excavating den sites. It also damaged wind-break plantings, but control operations, and widespread clearance of habitat providing cover for them, largely restricted browsing damage to the cliffs. On Kawau I. the negative effects of rock-wallabies were similar, but less severe.

The single species in this genus is superficially like the Notamacropus wallabies, but is classified into a separate genus because it has several distinguishing features: a smaller chromosome number; primarily browsing feeding habits; different dentition;44 and a gestation period longer than the oestrous cycle, a rare characteristic for marsupials.64

information on parasites is available, except that two species of boopid lice, Heterodoxus ampullatus and Boopia notofusca, the first species of lice specific to marsupials reported in New Zealand, were found on a brush-tailed rock-wallaby from Kawau I.72

Control. Official control operations on Motutapu I. were sporadic in the late 1960s, then stopped until 1990. Then DOC mounted a campaign to eradicate both possums and brush-tailed rock-wallabies from Rangitoto I. and Motutapu I., because of the negative effect both species had on pohutukawa forests and on internationally important studies of the sequence of revegetation since the last eruption of Rangitoto in ~1400 CE.66 On 5 and 6 ­November 1990, 28 tonnes of 6-g 1080 baits were spread over Rangitoto I. from the air.74 The relative abundance of wallabies was estimated before and after the aerial operation by systematic spotlighting over designated segments of the road round the island. From mean counts of 15.7 and 28.4 wallabies seen per section in August and ­September 1990, and 1.8 in November, Pekelharing74 estimated a 93% kill. DOC continued intensive ground operations against rock-wallabies on Rangitoto I. throughout the 1990s, using cyanide baits, traps and hunting with dogs. In 1999 a helicopter survey using forward looking

Genus WALLABIA

SWAMP WALLABY Wallabia bicolor (Desmarest, 1804) Synonyms Kangurus bicolor Desmarest, 1804; Protemnodon bicolor (Desmarest, 1804); Macropus bicolor (­Desmarest, 1804). Also called black or black-tailed wallaby. Description Distinguishing marks – see Table 1.1. This, the largest of the wallabies on Kawau I., has a dark grey back, a yellow-buff belly, a light yellow cheek stripe, and orange markings around the base of the ears. The fur is generally regarded as coarse and unattractive.35 Chromosome number 2n = 11 in the male, 10 in the female.29 The male has two Y chromosomes with attached autosomes.93 Dental formula I 3⁄1 C 0⁄0 Pm 1⁄1 M 4⁄4 = 28.

21

64 – 692 (640–730) 697 (660–750) 13 (10.3–15.4) F (adults)

–

64 – 761 (690–860) 756 (720–850) 17 (12.3–20.5) M Australia

–

105 200 470 670 10.3 (5.5–14.5) F (all ages)

9

230 690 780 12.8 (11.8–13.8)

Body wt (kg)

Food Swamp wallabies are generalist herbivores,79 but they prefer to browse shrubs and forbs rather than eat grass. In Australia they browse trees and bushes;64 toxic species such as bracken (Pteridium esculentum) and hemlock (Conium maculatum); other species high in oil content such as manna gum (Eucalyptus viminalis);19 and fungi, a readily accessible source of protein.30 On Kawau I., swamp wallaby faecal pellets contained a high proportion of coarse unidentifiable material from dicotyledons but little grass.33 They chewed bark from Pinus radiata seedlings, and probably browsed karaka, mingimingi and lilies (Arum sp.),43 at all times of the day and night.

Sample size

Habitat In Australia the local distribution of the swamp wallaby is apparently linked with that of dense undergrowth, e.g. Queensland brigalow scrub, shrubland, heathland, pine plantations and coastal dunes. On Kawau I. its preferred habitat is the thick kānuka scrub on the northern part of the island, which often has an understorey of mingimingi (Cyathodes fasciculata), grass in more open areas, and occasional tree ferns (Cyathea dealbata) in wetter gully sites.

Sex

New Zealand (Fig. 1.3). Only on Kawau I., especially at the northern end.33

Head and body length (mm)

Tail length (mm)

Distribution World. Wallabia bicolor is restricted to eastern mainland Australia from Cape York to southern Victoria and southeastern South Australia. Five subspecies are commonly, although tentatively, recognised.23 The subspecies introduced to New Zealand was probably W. b. apicalis.105

2

History of colonisation Swamp wallabies were liberated on Kawau I. in ~1870 by Sir George Grey.105 Little is known about their establishment and increase, but the species has survived there for over a century.

M

Hind foot length (mm)

Measurements See Table 1.8.

Kawau I.

Reference

Field sign The footprints are considerably larger than those of the other wallabies on Kawau I. The faecal pellets are large and almost resemble a flattened cube.

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Table 1.8:  Body measurements of swamp wallabies in New Zealand and Australia.

22

1 – Family Macropodidae

Social organisation and behaviour Swamp wallabies are solitary except when breeding. The only intraspecific association is between mother and young, although groups of socially unrelated individuals may share a common feeding area.35 They are largely nocturnal, but remain active throughout the day between periods of sitting with their tail between their legs.19 Reproduction and development Nothing is known of reproductive behaviour or breeding in the swamp wallaby in New Zealand. In Australia they breed in most months of the year.19 Both sexes are sexually mature by 15–18 months. The gestation period (mean 37 days) is longer than the oestrous cycle (mean 31 days).73 Females mate again ~8 days before the first young is born, and implantation of the resulting blastocyst is delayed. Pouch life spans 8–9 months, but young at foot, up to 15 months old, can continue to suckle.64 Population dynamics There is no information on sex ratio of pouch young or adults, age structure, or mortality of swamp wallabies on Kawau I. or in Australia. On survey transects in the northern part of Kawau I., counts of their faecal pellets were higher than those of the dama and parma wallabies,33 but elsewhere on the island they are less abundant. Predators, parasites and diseases Nothing is known about predators or parasites; no diseases are recorded apart from dental caries.33 Adaptation to New Zealand conditions Kawau I. was probably a less than ideal place to release swamp wallabies, since most of the island had already been cleared for farming and/or forestry, and swamp wallabies do not easily adapt to feeding on pasture. The remaining forest was reduced to few species, with no dense undergrowth or diversity of browse. Perhaps this explains why the Kawau I. swamp wallabies are somewhat smaller than their relatives in Australia (Table 1.8). Significance to the New Zealand environment The swamp wallaby is confined to Kawau I., where it is comparatively uncommon and therefore unlikely to contribute much additional damage to that done by other wallaby species to indigenous vegetation or, as in Australia,64 exotic trees or seedlings.17 It is included with the other three wallaby species in plans for eradication from Kawau I., and

until then is managed with poisons and shooting27 (p. 21). It is classified as ‘Least Concern’ in Australia by IUCN. Acknowledgements All the wallaby chapters in the first edition were written by B. Warburton and R.M.F. Sadleir; in the second edition by B. Warburton; and in this edition by A.D.M. Latham and B. Warburton, and refereed by M. Eldridge and A. Veale. Citation format for all species in this chapter Latham ADM, Warburton B (2021) Macropus eugenii, M. r. rufogriseus, M. parma, M. dorsalis, Petrogale penicillata, Wallabia bicolor. In The Handbook of New Zealand Mammals. 3rd edn. (Eds CM King and DM Forsyth) Family Macropodidae, pp.  1–26. CSIRO Publishing, Melbourne.

REFERENCES

1. Alley P (unpubl.). 2. Anon. (2016) ‘Management of dama wallaby (Macropus eugenii) in the Bay of Plenty and Waikato regions, 2016–2026’. Bay of Plenty and Waikato Regional Councils, and Department of Conservation, Hamilton. 3. Auckland Regional Council (2007) ‘Animal pest management plans’. Auckland Regional Council, Auckland. 4. Batchelor TA (1980) The social organisation of the brush-tailed rock wallaby (Petrogale penicillata penicillata) on Motutapu Island. MSc thesis. University of Auckland, New Zealand. 5. Bay of Plenty Regional Council (2011) ‘Regional Pest Management Plan 2011–2016’. Bay of Plenty Regional Council, Whakatane. 6. Benes M (2001) The effects of dama wallaby (Macropus eugenii) and red deer (Cervus elaphus) on the native vegetation of the Okataina Scenic Reserve. MSc thesis. University of Waikato, New Zealand. 7. Bowie JY (1980) A study of the nematode fauna of Macropus rufogriseus fruticus and Macropus eugenii. MSc thesis. University of Canterbury, New Zealand. 8. Buchanan J (1876) On the botany of Kawau Island: physical features and causes influencing distribution of species. Transactions and Proceedings of the New Zealand Institute 9, 503–527. 9. Calaby JH (1995) Red-necked wallaby Macropus rufogriseus. In The Australian Museum Complete Book of Australian Mammals. (Ed. R Strahan) pp. 350–352. Reed Books, Chatswood, Australia. 10. Catt DC (1975) Growth, reproduction and mortality in Bennett’s wallaby (Macropus rufogriseus fruticus) in South Canterbury, New Zealand. MSc thesis. University of Canterbury, New Zealand. 11. Catt DC (1977) The breeding biology of Bennett’s wallaby (Macropus rufogriseus fruticus) in South Canterbury, New Zealand. New Zealand Journal of Zoology 4, 401–411. doi:10.1080/ 03014223.1977.9517965 12. Catt DC (1979) Age determination in Bennett’s wallaby, Macropus rufogriseus fruticus (Marsupialia), in South Canterbury, New Zealand. Australian Wildlife Research 6, 13–18. doi:10.1071/WR9790013 13. Catt DC (1981) Growth and condition of Bennett’s wallaby (Macropus rufogriseus fruticus) in South Canterbury, New Zealand. New Zealand Journal of Zoology 8, 295–300. doi:10.1080/ 03014223.1981.10427969

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14. Choquenot D, Warburton B (2000) Modelling the cost-effectiveness of wallaby control in New Zealand. In Proceedings of the 19th Vertebrate Pest Conference. 6–9 March, San Diego. (Eds TP Salmon and AC Crabb) pp. 169–174. University of California, Davis. 15. Coates J (unpubl.). 16. Commins PN, Clements B (2000) ‘Dama wallaby distribution in the Bay of Plenty’. Environment Bay of Plenty, Rotorua. 17. Di Stefano J (2004) The importance of ecological research for ecosystem management: the case of browsing by swamp wallabies (Wallabia bicolor) in commercially harvested native forests. Ecological Management & Restoration 5, 61–67. doi:10.1111/j.1442-8903. 2004.00170.x 18. Duignan PJ, Norman RJ, O’Keefe J, Horner G (2004) Health assessment of wallabies from Kawau Island. Surveillance 31, 16–18. 19. Edwards GP, Ealey EHM (1975) Aspects of the ecology of the swamp wallaby Wallabia bicolor (Marsupialia: Macropodidae). Australian Mammalogy 1, 307–317. 20. Eldridge MDB, Browning TL (2002) Molecular genetic analysis of the naturalized Hawaiian population of the brush-tailed rock-wallaby, Petrogale penicillata (Marsupialia: Macropodidae). Journal of Mammalogy 83, 437–444. doi:10.1644/1545-1542(2002)0832.0.CO;2 21. Eldridge MDB, Browning TL, Close RL (2001) Provenance of a New Zealand brush-tailed rock-wallaby (Petrogale penicillata) population determined by mitochondrial DNA sequence analysis. Molecular Ecology 10, 2561–2567. doi:10.1046/j.1365-294X.2001.01382.x 22. Eldridge MDB, Close RL (1995) Brush-tailed rock-wallaby Petrogle penicillata. In The Australian Museum Complete Book of Australian Mammals. (Ed. R Strahan) pp. 383–385. Reed Books, Chatswood, Australia. 23. Eldridge MDB, Coulson GM (2015) Family Macropodidae (kangaroos and wallabies). In Handbook of the mammals of the world. Vol. 5. Monotremes and marsupials. (Eds DE Wilson and RA Mittermeier) pp. 630–735. Lynx Edicions, Barcelona. 24. Eldridge MDB, Miller EJ, Neaves LE, Zenger KR, Herbert CA (2017) Extensive genetic differentiation detected within a model marsupial, the tammar wallaby (Notamacropus eugenii). PLoS One 12, e0172777. doi:10.1371/journal.pone.0172777 25. Esler AE (1971) Inner Islands of Hauraki Gulf: Challenger Island. DSIR Botany Division. 26. Flux JEC (unpubl.). 27. Gardiner A (2015) ‘Kawau Island wallaby control’. Wild Animal Control Services Ltd, for Department of Conservation, Warkworth. 28. Harris S, Yalden DW (Eds) (2008) Mammals of the British Isles: Handbook. 4th edn. The Mammal Society, Southampton. 29. Hayman DL (1977) Chromosome number – constancy and variation. In The Biology of Marsupials. (Eds B Stonehouse and P Gilmore) pp. 27–48. MacMillan Press, London. 30. Hollis CJ, Robertshaw JD, Harden RH (1986) Ecology of the swamp wallaby (Wallabia bicolor) in north-eastern New South Wales. I. Diet. Australian Wildlife Research 13, 355–365. doi:10.1071/WR9860355 31. Hondelink P (unpubl.). 32. Johnston PG, Sharman GB (1979) Electrophoretic, chromosomal and morphometric studies on the red-necked wallaby, Macropus rufogriseus (Desmarest). Australian Journal of Zoology 27, 433–441. doi:10.1071/ZO9790433 33. Kinloch DI (1973) Ecology of the parma wallaby, Macropus parma Waterhouse, 1846, and other wallabies on Kawau Island New Zealand. MSc thesis. University of Auckland, New Zealand. 34. Kirkpatrick TH (1964) Molar progression and macropod age. Queensland Journal of Agricultural Science 21, 163–165.

35. Kirkpatrick TH (1970) The swamp wallaby in Queensland. Queensland Journal of Agricultural Science 96, 335–336. 36. Kirkpatrick TH (1995) Black-striped wallaby Macropus dorsalis. In The Australian Museum Complete Book of Australian Mammals. (Ed. R Strahan) pp. 237–238. Reed Books, Chatswood, Australia. 37. Knowlton JE (1984) A sighting device for estimating molar index to detemine age from macropod skulls. Australian Wildlife Research 11, 451–454. doi:10.1071/WR9840451 38. Knowlton JE, Panapa N (1982) Dama Wallaby Survey, Okataina Scenic Reserve. New Zealand Forest Service. 39. Knowlton JE, Sadleir R, White AJ (unpubl.). 40. Latham ADM, Latham MC, Warburton B (2019) Current and predicted future distributions of wallabies in mainland New Zealand. New Zealand Journal of Zoology 46, 31–47. doi:10.1080/0 3014223.2018.1470540. For costs, see Latham ADM, Latham MC, Warburton B (2016) 'Review of current and future predicted distributions and impacts of Bennett's and dama wallabies in mainland New Zealand.' MPI Technical Paper No. 2016/15. New Zealand Ministry for Primary Industries, Wellington. 41. Latham ADM, Latham MC, Norbury GL, Forsyth DM, W ­ arburton B (2020) A review of the damage caused by invasive wild mammalian herbivores to primary production in New Zealand. New Zealand Journal of Zoology 47, 20–52. 42. Le Page SL, Livermore RA, Cooper DW, Taylor AC (2000) Genetic analysis of a documented population bottleneck: introduced Bennett’s wallabies (Macropus rufogriseus rufogriseus) in New ­ Zealand. Molecular Ecology 9, 753–763. doi:10.1046/j.1365-294x. 2000.00922.x 43. Lentle R (unpubl.). 44. Lentle RG, Hume ID, Stafford KJ, Kennedy M, Haslett S, Springett BP (2003) Comparison of tooth morphology and wear patterns in four species of wallabies. Australian Journal of Zoology 51, 61–79. doi:10.1071/ZO01078 45. Lentle RG, Hume ID, Stafford KJ, Kennedy M, Haslett S, Springett BP (2003) Comparisons of indices of molar progression and dental function of brush-tailed rock-wallabies (Petrogale penicillata) with tammar (Macropus eugenii) and parma (Macropus parma) wallabies. Australian Journal of Zoology 51, 259–269. doi:10.1071/ZO02007 46. Lentle RG, Hume ID, Stafford KJ, Kennedy M, Springett BP, Haslett S (2003) Differences in renal and alimentary water conservation account for differences in the distribution of tammar and parma wallabies on Kawau Island, New Zealand. Australian Journal of Zoology 51, 371–385. doi:10.1071/ZO02074 47. Lentle RG, Potter MA, Springett BP, Stafford KJ (1999) Bait consumption and biology of tammar wallabies in the Rotorua region. Conservation Advisory Science Notes 221, 1–18. 48. Lentle RG, Potter MA, Stafford KJ, Springett BP, Haslett S (1998) The temporal characteristics of feeding activity in free-ranging tammar wallabies (Macropus eugenii Desmarest). Australian Journal of Zoology 46, 601–615. doi:10.1071/ZO98039 49. Lentle RG, Stafford KJ, Potter MA, Springett BP, Haslett S (1998) Incisor and molar wear in the tammar wallaby (Macropus eugenii Desmarest). Australian Journal of Zoology 46, 509–527. doi:10.1071/ ZO98025 50. Lentle RG, Stafford KJ, Potter MA, Springett BP, Haslett S (1998) The temporal character of feeding behaviour in captive tammar wallabies (Macropus eugenii Desmarest). Australian Journal of Zoology 46, 579–600. doi:10.1071/ZO98027 51. Lentle RG, Stafford KJ, Potter MA, Springett BP, Haslett S (1999) Ingesta particle size, food handling and ingestion in the tammar wallaby (Macropus eugenii Desmarest). Australian Journal of Zoology 47, 75–85. doi:10.1071/ZO98038

1 – Family Macropodidae

52. Lentle RG, Stafford KJ, Potter MA, Springett BP, Haslett S (1999) Temporal patterns of drinking in the tammar wallaby (Macropus eugenii Desmarest). Australian Journal of Zoology 47, 67–73. doi:10.1071/ZO98035 53. Llewellyn MC (1988) Assessment of Wallaby Populations Poisoned with 1080 Impregnated Baits. Lake Okataina Scenic Reserve and Makatiti Dome. Department of Conservation, Rotorua. 54. Macdonald DW (Ed.) (2001) The New Encyclopedia of Mammals. Oxford University Press, Oxford. 55. Mason PC (1975) New parasite records from the South Island. New Zealand Veterinary Journal 23, 69. doi:10.1080/00480169.1975.34198 56. Maynes GM (1973) Reproduction in the parma wallaby, Macropus parma Waterhouse. Australian Journal of Zoology 21, 331–351. doi:10.1071/ZO9730331 57. Maynes GM (1974) Occurrence and field recognition of Macropus parma. Australian Zoologist 18, 72–87. 58. Maynes GM (1977) Breeding and age structure of the population of Macropus parma on Kawau Island, New Zealand. Australian Journal of Ecology 2, 207–214. doi:10.1111/j.1442-9993.1977.tb01138.x 59. Maynes GM (1977) Distribution and aspects of the biology of the parma wallaby, Macropus parma, in New South Wales. Australian Wildlife Research 4, 109–125. doi:10.1071/WR9770109 60. Maynes GM (1995) Parma wallaby Macropus parma. In The Australian Museum Complete Book of Australian Mammals. (Ed. R Strahan) pp. 342–344. Reed Books, Chatswood. 61. Maynes GM (2008) Parma wallaby, Macropus parma. In The Mammals of Australia. 3rd edn. (Eds S Van Dyck and R Strahan) pp. 341–343. Reed New Holland, Sydney. 62. McKenzie LM, Cooper DW (1995) Conservation genetics of the parma wallaby Macropus parma: a case study for Australian marsupials. Pacific Conservation Biology 2, 150–156. doi:10.1071/PC960150 63. McLeod S (1986) The feeding and behavioural interaction of Bennett’s wallaby (Macropus rufogriseus rufogriseus) with domestic sheep (Ovis aries) in South Canterbury, New Zealand. MSc thesis. University of Canterbury, New Zealand. 64. Merchant JC (1995) Swamp wallaby Wallabia bicolor. In The Australian Museum Complete Book of Australian Mammals. (Ed. R Strahan) pp. 404–405. Reed Books, Chatswood. 65. Merchant JC, Calaby JH (1981) Reproductive biology of the rednecked wallaby (Macropus rufogriseus banksianus) and Bennett’s wallaby (M. r. rufogriseus) in captivity. Journal of Zoology 194, 203–217. doi:10.1111/j.1469-7998.1981.tb05769.x 66. Miller CJ, Craig JL, Mitchell ND (1994) Ark 2020: a conservation vision for Rangitoto and Motutapu Islands. Journal of the Royal Society of New Zealand 24, 65–90. doi:10.1080/03014223.1994.9517456 67. Morgan DM, Copland AJ (1985) Geographic Distribution of Possums (Trichosurus vulpecula) and Rock Wallabies (Petrogale penicillata) on Rangitoto Island. New Zealand Forest Service, Auckland. 68. Morriss GA, O’Connor CE (2001) Palatability of Feracol® for dama wallaby (Macropus eugenii) control. Conservation Advisory Science Notes 340, 1–3. 69. Morriss GA, O’Connor CE, Warburton B, Eason CT (2000) Alternative Toxicants for Dama Wallaby (Macropus eugenii) control. Landcare Research, Lincoln. 70. Mowbray SC (2002) Eradication of introduced Australian marsupials (brushtail possum and brushtailed rock wallaby) from Rangitoto and Motutapu Islands, New Zealand. In Turning the Tide: The Eradication of Invasive Species. (Eds CR Veitch and MN Clout) pp. 226–232. International Union for Conservation of Nature and Natural Resources Species Survival Commission, Invasive Species Specialist Group, International Union for Con-

servation of Nature and Natural Resources, Gland, Switzerland, and Cambridge UK. 71. Murphy CR, Smith JR (1970) Age determination of pouch young and juvenile Kangaroo Island wallabies. Transactions of the Royal Society of South Australia 94, 15–20. 72. Palma RL (1996) First records of marsupial lice (Insecta: Phthiraptera: Boopidae) on a brushtailed rock wallaby from New Zealand. New Zealand Journal of Zoology 23, 161–164. doi:10.1080 /03014223.1996.9518075 73. Paplinska JZ, Moyle RLC, Temple-Smith PDM, Renfree MB (2006) Reproduction in female swamp wallabies, Wallabia bicolor. Reproduction, Fertility and Development 18, 735–743. doi:10.1071/RD06024 74. Pekelharing CJ (1991) Changes in Possum and Wallaby Numbers Following an Aerial Control Operation on Rangitoto Island in 1990. Forest Research Institute, Christchurch. 75. Ross J, Hix S, Guilford G, Thompson S, Shapiro L, MacMorran D, Eason C (2011) Effectiveness of cyanide pellets for control of Bennett’s wallaby (Macropus rufogriseus rufogriseus) in New Zealand. New Zealand Journal of Zoology 38, 185–188. doi:10.1080/03014223. 2010.548074 76. Russell EM (1974) The biology of kangaroos (Marsupialia – Macropodidae). Mammal Review 4, 1–59. doi:10.1111/j.1365-2907.1974.tb00347.x 77. Sadleir RMF (unpubl.). 78. Sadleir RMF, Tyndale-Biscoe CH (1977) Photoperiod and the termination of embryonic diapause in the marsupial Macropus eugenii. Biology of Reproduction 16, 605–608. doi:10.1095/ biolreprod16.5.605 79. Sanson GD (1989) Morphological adaptations of teeth to diets and feeding in the Macropodidae. In Kangaroos, Wallabies and Rat Kangaroos. (Eds G Grigg, P Jarmin and I Hume) pp. 151–168. Surrey Beatty, Sydney. 80. Shapiro L, Ross J, Adams P, Keyzer R, Hix S, MacMorran D, Cunningham C, Eason C (2011) Effectiveness of cyanide pellets for control of dama wallabies (Macropus eugenii). New Zealand Journal of Ecology 35, 287–290. 81. Sharman GB, Maynes GM (1995) Rock-wallabies Petrogale, Peradorcas. In The Australian Museum Complete Book of Australian Mammals. (Ed. R Strahan) pp. 363–364. Reed Books, Chatswood, Australia. 82. Short J (1982) Habitat requirements of the brush-tailed rock-wallaby, Petrogale penicillata, in New South Wales. Australian Wildlife Research 9, 239–246. doi:10.1071/WR9820239 83. Smith MJ, Hinds L (1995) Tammar wallaby Macropus eugenii. In The Australian Museum Complete Book of Australian Mammals. (Ed. R Strahan) pp. 329–331. Reed Books, Chatswood, Australia. 84. Strickland RR (1994) Distribution of Dama Wallabies in the Bay of Plenty. Department of Conservation, Rotorua. 85. Studholme EC (1954) Te Waimate. Early Station Life in New Zealand. AH & AW Reed, Dunedin. 86. Sunnucks P, Taylor AC (1997) Sex of pouch young related to maternal weight in Macropus eugenii and M. parma (Marsupialia: Macropodidae). Australian Journal of Zoology 45, 573–578. doi:10.1071/ZO97038 87. Szymanik MI (1987) The ecology of the brush-tail rock wallaby (Petrogale penicillata penicillata) on Rangitoto Island. MSc thesis. University of Auckland, New Zealand. 88. Taggart DA, Schultz D, White C, Whitehead P, Underwood G, Phillips K (2005) Cross-fostering, growth and reproductive studies in the brush-tailed rock-wallaby, Petrogale pencillata (Marsupialia: Macropodidae): efforts to accelerate breeding in a threatened marsupial species. Australian Journal of Zoology 53, 313–323. doi:10.1071/ ZO05002

25

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89. Taylor AC, Cooper DW (1999) Microsatellites identify introduced New Zealand tammar wallabies (Macropus eugenii) as an ‘extinct’ taxon. Animal Conservation 2, 41–49. 90. Taylor CM (1990) Assessment of the regeneration potential of a disturbed native forest subject to continued marsupial browse: Some management options for Kawau Island. MSc thesis. University of Auckland, New Zealand. 91. Thomson GM (1922) The Naturalisation of Animals & Plants in New Zealand. Cambridge University Press, Cambridge, UK. 92. Tomich PQ (1986) Mammals in Hawaii. Bishop Museum Press, Honolulu. 93. Tyndale-Biscoe CH (1973) Life of Marsupials. Edward Arnold, London. 94. Vujcich MV (1979) Aspects of the biology of the parma (Macropus parma Waterhouse) and dama (Macropus eugenii Desmarest) wallabies with particular emphasis on social organisation. MSc thesis. University of Auckland, New Zealand. 95. Vujcich VC (1979) Feeding ecology of the parma, Macropus parma (Waterhouse) and tammar Macropus eugenii (Desmarest) wallabies on Kawau Island. MSc thesis. University of Auckland, New Zealand. 96. Waikato Regional Council (2014) Waikato Regional Pest Management Plan 2014–2024: Part 2: Pest Management Programmes. Waikato Regional Council, Hamilton. 97. Wallace SW, Wallace GT (1995) The Impact of Dama Wallaby (Macropus eugenii) on Forest Understoreys in Lake Okataina Scenic Reserve. Department of Conservation, Rotorua. 98. Warburton B (1986) Wallabies in New Zealand: history, current status, research, and management needs. Forest Research Institute Bulletin 114, 1–29. 99. Warburton B (1990) Control of Bennett’s and tammar wallabies in New Zealand using compound 1080 gel on foliage baits. Australian Wildlife Research 17, 541–546. doi:10.1071/WR9900541

100. Warburton B (1995) Biology, Population Dynamics and Habitat Range of Bennett’s Wallaby. Landcare Research, Lincoln. 101. Warburton B, Frampton CM (1993) Monitoring Bennett’s Wallaby in South Canterbury. Landcare Research, Lincoln. 102. Weaver R (unpubl.). 103. Williams D (2001) Aussie immigrants wreak havoc in New Zealand’s Bay of Plenty. Bait stations for maintenance control of dama wallaby (Macropus eugenii). Proceedings of the 12th Australasian Vertebrate Pest Conference. 21–25 May, Melbourne. pp. 347–351. (Ed. Anon.) Department of Natural Resources and Environment, Melbourne. 104. Williamson GM (1986) The ecology of the dama wallaby (Macropus eugenii Desmarest) in forests at Rotorua, with special reference to diet. MSc thesis. Massey University, New Zealand. 105. Wodzicki K, Flux JEC (1967) Guide to introduced wallabies in New Zealand. Tuatara 15, 47–59. 106. Wodzicki K, Flux JEC (1967) Re-discovery of the white-throated wallaby, Macropus parma Waterhouse 1846, on Kawau Island, New Zealand. Australian Journal of Science 29, 429–430. 107. Wodzicki K, Flux JEC (1971) The parma wallaby and its future. Oryx 11, 40–47. doi:10.1017/S0030605300009431 108. Wodzicki KA (1950) ‘Introduced mammals of New Zealand: an ecological and economic survey’. DSIR Bulletin 98, Wellington. 109. Woinarski JCZ, Burbidge AA, Harrison PL (Eds) (2014) The Action Plan for Australian mammals 2012. CSIRO Publishing, Melbourne. 110. Wright S (2017) ‘The impact of dama wallaby (Macropus eugenii) and red deer (Cervus elaphus) on forest understorey in the Lake Okataina Scenic Reserve – 2017 update’. Department of Conservation, unpublished report: DOC-3223478, Wellington. 111. Yalden D (1999) The History of British Mammals. Academic Press, London.

Plate 1: Wallabies

Bennett’s wallaby

Swamp wallaby

Black-striped wallaby (extinct)

Brush-tailed rock wallaby

Dama wallaby

Parma wallaby

27

28

Plate 2: Brushtail possum and hedgehog

Brushtail possum grey form

Brushtail possum black form

Brushtail possum brown form

Hedgehog

Plate 3: Bats

New Zealand long-tailed bat

Little red flying fox (not to scale) Lesser short-tailed bat

Greater short-tailed bat

29

30

Plate 4: Rodents Norway rat

Ship rat, alexandrinus morph

Ship rat, frugivorus morph

Ship rat, rattus morph white-bellied form

House mouse grey-bellied form

Kiore

Plate 5: Eared seals female

male

New Zealand sea lion

female

male

Subantarctic fur seal

New Zealand fur seal

female

male

31

32

Plate 6: Earless seals

Crabeater seal

Weddell seal

Leopard seal

Ross seal

Southern elephant seal

male

female

Plate 7: Lagomorphs and companion animals

Border collie

Kur¯ı

Feral cat

Brown hare

‘Mad March’ hares

European rabbit

33

34

Plate 8: Mustelids

Common weasel

Stoat

male, summer

female, winter

pied (not to scale)

Ferret

Plate 9: Feral livestock (1) Feral pig

Feral horse

Kunekune

Feral cow

35

36

Plate 10: Feral livestock (2)

Feral goat

male

female

male

Feral sheep

male female

Plate 11: Mountain bovids male, summer

female, winter

Alpine chamois

male, winter

Himalayan tahr

female, summer

37

38

Plate 12: Widespread deer male, summer

Western red deer

calf

female, winter

male, common phase, summer female, menil phase

female, common phase, winter

Common fallow deer

young male, black phase

young male, white phase

Sika deer

Plate 13: Localised deer

male

White-tailed deer

male

female

female

Rusa deer

male

male

Sambar deer female

female

39

40

Plate 14: Localised, rare or extinct deer Wapiti

male

Chital

male female

female

male

Moose

female calf

Plate 15: North Island

173° E

174° E 35° S

35° S 175° E

173° E 176° E

36° S

36° S

178° W 37° S

37° S 178° E

177° E

30°00ʹ S 38° S 38° S

31°00ʹ S

38° S 39° S

178° E 40° S 40° S 173° E

177° E 41° S

41° S

173° E

174° E

175° E

176° E

41

Plate 16: South Island

42

35° S

174° E

173° E

172° E

41° S

41° S

171° E

42° S

42° S

170° E 174° E 43° S

43° S

169° E

168° E 44° S 44° S

172° E

173° E

167° E

45° S

44° S

45° S

176°30ʹ W

166° E

46° S 46° S 171° E

166° E 50°30ʹ S

50°30ʹ S

166° E 47° S 47° S

169° E

170° E 52°30ʹ S 167° E

168° E

169° E

2

Family Phalangeridae

The Family Phalangeridae is the second and smaller of the two families of marsupials represented in New ­Zealand. Phalangerids are classified into two tribes, the ­Trichosurini (one species of Wyulda, the scaly-tailed possum, plus three species of brushtail possums, Trichosurus, native to forests in Australia); and the Phalangerini (>10 species of cuscuses native to Papua New Guinea, and adjacent islands between Sulawesi and the Solomons). All weigh 1.5–5 kg and are mainly arboreal.208,350

Genus TRICHOSURUS The brushtail possums all have large ears, pointed faces, close woolly fur and bushy tails. Only the common brushtail possum, Trichosurus vulpecula, was introduced to New Zealand, in several colour phases (Plate 2). It is the most widespread of the three brushtail possum species in Australia, found throughout eastern, central, and southwestern wooded and forested areas.

BRUSHTAIL POSSUM Trichosurus vulpecula (Kerr, 1792) Synonym T. fuliginosus Ogilby, 1831. For further synonyms see Jackson.208 In New Zealand, the common name was formerly ‘opossum’,61,225 but this invited confusion with the entirely different American opossum, Didelphis sp. In Australia, the more frequent usage is ‘possum’396 and the

standard common name adopted by the Australian Mammal Society is ‘common brushtail possum’361 or, where it is the only resident species, as here, simply ‘possum’. Description The possum has a thick bushy tail (Latin trichosurus = hairy tail), a pointed snout and long, fox-like tapering ears (Latin vulpecula = little fox), and a darkly stained sternal gland. Size and weight vary greatly around New Zealand (Tables 2.1, 2.2). There are two general colour forms, grey and black, each with much variation. Greys are mainly a clear grizzled grey on the back and sides of the body, with the face pale grey, darker around the eyes and sides of the snout, and white at the base of the ears. The outer sides of the limbs are a uniform grizzled grey, often darker medially and posteriorly. The chin is dark, but the throat, chest, belly, and inner sides of the limbs are white or dirty yellow. The sternal gland stains the fur a dark rusty red, more prominently in males than females; juveniles have only a faint grey streak. The fur around the pouch of females and at the base of the tail is often stained brownish. The tail has bushy grey fur changing abruptly to black at about the midpoint (the extreme tip may be white in ~5% of animals), and naked on its ventral surface for the last 50–80 mm. Blacks are generally deep umber-brown tinged with rufous, paler on the forequarters, sides and below, darker

44

The Handbook of New Zealand Mammals

Table 2.1:  Geographical variation in bodyweights of adult possums in New Zealand. Latitude in decimal degrees.

Bodyweight (kg) Locationa

Latitude (°S)

Habitatb

n

Mean

Maximum

Reference 384

North I. Waipoua SF

35.65

N

178

2.51

>3.0

Kawau I.

36.42

N/F

158

1.83

2.63

357

Silverdale

36.62

F

94

2.39

>3.3

393

Urewera NP

38.22

N

103

2.56

–

302

Tokoroa

38.25

E

>150

2.75

4.90

69

Taranaki, SF 91

38.93

E

105

2.58

>3.60

64

Patea/Waitotara

39.75

F

100

2.25

3.10

425

Havelock North

39.90

F

56

2.40

3.85

421

Wanganui

40.00

F

82

2.32

3.95

100

Akitio

40.60

F/N

41

2.40

3.60

316

Castlepoint

40.83

F

728

2.40

4.00

207

Kapiti I.

40.85

N

1043

2.81

4.50

100

Whareama

40.90

F

40

2.40

3.60

100

Wainuiomata Valley

41.33

N

76

2.66

3.55

41

Orongorongo Valley

41.35

N

196

2.40

3.70

110

Pararaki

41.53

N

127

2.18

–

84

South I. Tennyson Inlet

41.10

F/N

100

2.51

3.73

40

Rai Valley

41.25

F/N/E

211

2.58

4.45

356

Waimangaroa

41.72

F/N

25

3.17

3.89

164

St Arnaud

41.83

N

97

2.95

4.40

379

Mt Misery

41.92

N

139

3.16

4.45

72

Kaikoura

42.33

F/N

19

3.50

4.26

164

Claverly

42.60

F/N

176

3.12

–

417

Mt Bryan O’Lynn

42.63

N

224

2.85

4.20

82

Kumara

42.67

N/E

159

2.85

4.50

356

Taramakau River

42.75

N

96

3.10

4.10

405

Kokatahi

42.92

N

37

3.10

–

164

Hokitika River

42.97

N

2177

3.12

>4.5

34

Mt Thomas

43.15

E

20

2.78

>3.30

438

Ashley SF

43.22

E

264

2.80

–

410

Karangarua River

43.52

N

35

3.30

4.45

160

Copland Valley

43.62

N

134

3.47

6.30

158

Banks Peninsula

43.67

F/N

590

3.53

5.14

164

Dunedin

45.80

N

58

2.27

3.30

356

Waitahuna

45.92

E

95

2.56

3.40

38

Riverton

46.37

N/E/F

236

2.49

4.30

356

Codfish I.

46.75

N

34

3.28

–

175

Stewart I.

47.00

N

194

3.06

4.82

357

Chatham I.

43.90

N/F

214

3.10

4.67

357

a. SF, State Forest; NP, National Park. b. N, native forest; F, farmland with scrub; E, exotic forest.

2 – Family Phalangeridae

Table 2.2:  Linear measurements of the possum in New Zealand (mean ± s.d.). Latitude in decimal degrees.

Location Silverdale, Auckland

Latitude (°S)

Sex

n

Total length (mm)

Tail length (mm)

Head length (mm)

36.62

M

40

786

321

89

F

54

782

319

88

25

787 ± 59

322 ± 28

99 ± 7

Bridge Pa, Hawke’s Bay

39.72

M F

28

786 ± 49

319 ± 19

101 ± 8

Whareama, Wairarapa

40.90

M

20

780 ± 47

297 ± 18

97 ± 6

F

20

436 ± 77

300 ± 24

101 ± 8

328 ± 15

92 ± 3

Orongorongo Valley

41.37

M

60

890 ± 37

F

60

788 ± 27

326 ± 15

90 ± 3

Mt Misery, Nelson

41.92

M

62

831 ± 47

356 ± 21

96 ± 5

F

45

829 ± 34

351 ± 19

95 ± 4

M

31

840 ± 36

–

–

F

50

820 ± 41

–

–

Taramakau River, Westland

42.75

Data from Voller,405 Clout et al.,72 Triggs395 and Brockie 41.

along the posterior back. The ears have little or no white at the base, and the tail is nearly wholly black (though occasionally also with a white tip). Staining from the sternal gland is less obvious than in greys. Possums moult continuously but with one major period of shedding,272 which in the Orongorongo Valley is in August–November.100 The iris of the eye is brown, the vibrissae long and well developed. The hand and foot both have five digits, each with a strong curved claw and pronounced palmar pads and striations. The second and third digits of the foot are syndactylous (i.e. joined for most of their length) and bear elongated claws used in grooming. The first toe is well developed, opposed to the rest of the toes, and has no claw. There is a fully formed pouch with two mammaries and forward-directed opening, corresponding to Type 5 parental care as defined by Russell.339 The testes descend permanently into the scrotum, which is pendulous and prominently situated anterior to the penis. Possums have three basic gaits:216,432 walking, along horizontal and up gently inclined surfaces; half-bounds, jumping from branch to branch or up steeply inclined surfaces or in long grass; and bounds, up steeply inclined and vertical surfaces, such as tree trunks.169 The prehensile tail maintains its grip until all feet have shifted from one branch to the next. Possums can swim, reluctantly; one was sighted off Kapiti I., rafting on a floating log.224

The skull is stout and heavily built. The nasals are smoothly convex above, with a shallow nasal notch; the forehead is flattened; the interorbital region is narrow, concave along its centre, its edges sharply ridged; the palate is fenestrated; the anterior palatine foramina run back level with the canines; the posterior palatal vacuities extend from the back of the first molar nearly to the hind edge of the palate, bounded only by a narrow transverse strip of bone; the bullae are low, flattened, and scarcely inflated. Chromosome number 2n = 20.181 Dental formula I 3⁄2 C 1⁄0 Pm 2⁄1 M 4⁄4 = 34. Field sign Tracks (‘pads’ or ‘runs’) are often evident where possums emerge from forest out on to pasture to feed, and are also visible in forest when possum numbers are high.317 Trees frequently bear extensive surface scratches. Bark biting, usually a series of horizontal scars on a variety of native and introduced trees and shrubs, may have social ­importance as a visual sign.226 Faecal pellets are usually ~15–30 mm long, 5–14 mm wide, crescent shaped, slightly pointed at the ends, and found singly or in groups; colour and texture vary with diet. Leaves browsed by possums have torn rather than cut edges, with the midrib and lower part of the leaf often partly remaining, unlike insect browse.253 Possums are destructive feeders, leaving the

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ground littered with broken branches, discarded leaves, or partly eaten fruits. Dark brown urine trails may be seen, particularly if possums have been feeding on kāmahi (Weinmannia racemosa) or five-finger (Pseudopanax arboreus) leaves.35 Measurements Males and females differ little in size or weight.139 In nine separate studies, mean adult female weight was 98.6% that of males, but the asymptotic weight (and presumably size) of males calculated from growth curves consistently exceeds that of females.69 Variation Subspecies. Six subspecies are recognised.208 Only T. v. vulpecula from south-eastern Australia, and the largersized and more robust T. v. fuliginosus from Tasmania, were brought to New Zealand.314 Body size. (See Tables 2.1, 2.2.) In the North I., populations on farmland (2.36 ± 0.03 kg) are significantly lighter than those from native or exotic forests (2.54 ± 0.06 kg). North I. populations in general (n = 13; 2.45 ± 0.04 kg) are significantly lighter than South I. ones (n = 17; 3.04 ± 0.08  kg). The north–south cline in body and skull size and bodyweight is closely correlated with mean annual temperature, as predicted by Bergmann’s Rule.438 Colour. Black possums predominate in the Kaimai Range, Urewera NP and East Cape in the North I., and in Westland, Fiordland and western Southland in the South I., many of which are high-rainfall areas.313 Greys predominate on farmland and in drier, open country on both main islands, though there are exceptions where founder effects remain; e.g. only black possums were introduced to main Chatham and Codfish islands. There have been no major changes in the broad pattern of coat colour variation since the 1950s. The New Zealand fur trade currently recognises four different colours of skins.37 Natural dark brown and redbrown are varieties of the brown/black form, while rusty and pale are varieties of grey. Red-necks, a variety of rusty, are usually grey, with a pronounced browning of the shoulder fur. The grey and black forms are probably the only true-breeding colour types; pales can be found with brown offspring, and browns with pale offspring. Most fur is now traded as plucked (loose) hair, rather than full pelts, and spun with merino wool into luxury garments (p. 58).

Dentition. Highly variable. The frequency of occurrence of the most common variants, missing canines or first premolars in the upper jaw, is often higher in New ­Zealand (8–45%) than in Australia (8%).100 I2 is often minute; other very small teeth (probably Pm1 and Pm3) may also be present in front of the lower premolar; and missing or extra incisors and molars are frequent. Only 49% of 350 skulls from Banks Peninsula had the ‘standard’ dental formula.164 History of colonisation Possums were introduced to establish a fur trade similar to that flourishing in Australia at the time. The first successful release was in forest behind Riverton, Southland, in 1858 by C. Basstian, at the same place where possums had been unsuccessfully released some 20 years earlier.314 Most importations were made by the regional acclimatisation societies, particularly between 1890 and 1900. The total imports numbered only ~200–300 individuals; more than half (58% of recorded shipments) were from Tasmania, and 74% of all imports were the black form. Tasmanian blacks, particularly favoured for their large size and superior fur quality, were all released in the South I., except for a few taken to Paraparaumu and Lake ­Waikaremoana. Greys imported from mainland A ­ ustralia (Gippsland and New South Wales) were released primarily in the Catlins district and near Dunedin and Auckland. The sources and patterns of these introductions have partly determined the present pattern of possum variation in New Zealand. For example, there is still a strong negative correlation between the percentage of black possums in a population and the proportion of its gene pool that came from mainland Australia.377 Mixing between populations originating from mainland and Tasmanian introductions may still be incomplete in some areas, such as Hawke’s Bay.346 Australian stock accounts for only ~8% of recorded releases. The consequent spread of possums was accelerated by additional releases of the New Zealand-bred progeny of the original introductions. About half of these had official government approval by the acclimatisation societies and private individuals equally, and the rest were illegal, i.e. the unrecorded efforts of private individuals. Assisted dispersal of possums was most vigorous between 1890 and 1940. Illegal releases were particularly common from 1920 to 1940,314 and occasionally continue.223

2 – Family Phalangeridae

The release and dispersion of possums in New Zealand were strongly influenced by fluctuating public attitudes and government policy. Initially possums were considered to be ‘creating a valuable industry’,423 but in the southern Longwoods and the Catlins, there was extensive uncontrolled trapping for skins by 1890. To restrain the destruction of this valuable resource, the government in 1889 (urged by the Southland Acclimatisation Society) brought the possum under the Protection of Animals Act 1880. Complaints by settlers near Riverton of damage by possums to crops and pasture (apparently in support of a case for continued trapping) then prompted the government to enquire in 1891 from the governments of New South Wales, Victoria and Tasmania for ‘any information as to the destructions of the opossum in orchards, gardens, etc.’. All replies were similar to that from Tasmania, that ‘the damage done by opossums … is very small, and amply compensated by the commercial value of their skins’.423 The conflict of interests between the acclimatisation societies and farmers, orchardists and conservationists resulted in several contradictory changes of legislation. Increasing trapping of possums prompted the 1911 declaration of possums as imported game under the Animal Protection Act 1908. In 1912, protection was withdrawn after pressure from possum trappers. In 1913, further outcry from the acclimatisation societies resulted in an Order in Council granting possums absolute protection in practically all the bush-covered districts of New  ­Zealand. Wholesale poaching remained rife, however, and thousands of skins were exported, nominally as rabbit skins.389 After continuing debate, in 1919 the government requested Professor H.B. Kirk to investigate possum damage to forests. Kirk 232 concluded, ‘The damage to New Zealand forests is negligible and is far outweighed by the advantage that already accrues to the community’, and ‘Opossums may, in my opinion, with advantage be liberated in all forest districts except where the forest is fringed by orchards or has plantations of imported trees in the neighbourhood’. He recommended a May–July open season under licence. In 1921, legislation laid down the procedure for the taking of possums, and prohibited the harbouring and release of possums without permission from the Department of Internal Affairs (DIA). Skins could be sold only to licensed dealers, only stamped skins could be sold, and a levy was charged for stamping. The administration of these provisions was partly

controlled by the acclimatisation societies, for which they received part of the royalties. After 1922, there was increasing evidence of the detrimental effects of possums on native forests. DIA took a firm stand and, despite Kirk’s recommendations, refused to sanction any of the repeated applications for further releases.314 Uncontrollable illegal releases therefore increased greatly. The general tide of opinion eventually swung against protection of possums, and in 1946–47 all restrictions on the taking of possums were cancelled, penalties for harbouring and release were increased, and limited poisoning was legalised. For post-war control operations, see p. 63. Distribution World. The brushtail possum is endemic to mainland Australia, Tasmania and some offshore islands.362 It has the widest distribution of any marsupial in Australia. Numbers are increasing in many urban areas in A ­ ustralia358 and in Tasmania following conversion of woodland to pasture.88 In the arid regions of Australia, however, possum populations are being reduced by fox and cat predation and by changes in the fire regime.157 New Zealand (Fig. 2.1). Possums are found throughout the North I., except for the upper slopes of Mts Taranaki and Ruapehu, and in a few parts of northern Auckland province. Northland was completely colonised only in the 15 years before 2004. Possums are widespread in the South I., except in the wettest parts of south Westland and western Fiordland, and in the upper catchments of a few rivers in South Canterbury and north-west Otago.68 Dispersal continues, e.g. possums invaded the upper Copland and Karangarua Valleys only in the late 1970s.370 In the 1990s, possums were scarce south of Haast and absent south of the Arawata River, except around Milford Sound, but were spreading down the west side of Lake Te Anau and into the south-west of the South I. By 2017 possums were widespread through most of Fiordland, having colonised the south-western area over the past 20 years. They were found at high densities in coastal areas north of Milford Sound, and at moderate densities around Lakes Te Anau, Manapouri, Hauroko and Monowai. They remained patchy and at low densities along the western area between Doubtful Sound and Puseygur Point, and were still absent from most of the Mt Forbes peninsula, south of Doubtful Sound. Their distribution on the previously unoccupied western side between Doubtful Sound and Milford is not well known.430

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Figure 2.1:  Historical range expansion of possums up to 1998, with dates and locations of some of the original releases.68 For distribution on islands, see Table 2.3.

2 – Family Phalangeridae

Table 2.3:  Distribution and history of possums on the offshore and outlying islands of New Zealand and islands within inlets, lakes and harbours. List includes some islands of 8000 mm per year, and elevations up to 1800 m and 2400 m, respectively, in the South and North  I. mountain ranges, regularly foraging above the snow line in beech forest. Food Possums are best described as opportunistic herbivores, feeding mainly on leaves. They also eat buds, flowers, fruits, ferns, bark, fungi and invertebrates, which at times comprise most of the diet. Kean and Pracy’s early study228 listed more than 70 native tree species, 20 ferns and a few vines and epiphytes, as well as grasses, herbs, and sedges

eaten by possums. This list has subsequently been extended,174,278 particularly to podocarps such as Hall’s totara (Podocarpus hallii) and pahautea (Libocedrus bidwillii),278 and a wider range of fungi.433 Weeds such as briar (Rosa rubiginosa) and willow (Salix fragilis) are important foods in dry grass/shrubland ecosystems.167 Possums in alpine areas eat mostly woody plants and herbs.293 Cultivated grain and vegetable crops, horticultural produce, introduced ornamental shrubs, and flowers are also eaten.315 Possums readily eat meat, especially native birds and their eggs,47 and land snails;406 and they scavenge deer and pig carcasses, including those infected with bovine tuberculosis (bTB). Possums have pronounced preferences for some plants relative to their availability, although such preferences may be inconsistent between areas.148,369 Local diet varies because, in any one region, they tend to concentrate on only a few species and particular individual trees.83,127,147 Selection is influenced by the species composition of vegetation, except that some, e.g. fuchsia and mistletoes, are preferred wherever they are available.305,348,373 Other factors include the relative abundance of a given plant in the local habitat; plant growth forms; physical and nutritional properties of leaves, e.g. leaf age, digestibility and toxins; and the availability of other foods, e.g. fruits. Possum diet and foraging patterns are also influenced strongly by secondary metabolites and antifeedant chemicals in leaves.118,234–236,248,269 A field assay of food or food-based products for bait development suggested protein content was the most important determinant of possum food choice,206 and the severity of browsing on forest trees was related to the available nitrogen concentration of foliage (a measure of in vitro digestible protein).431 Diet also varies with sex, season, location and elevation.83 (Fig. 2.2). Seasonal shifts in diet reflect not only the changing availability of non-foliar foods and of foliage of preferred deciduous species, but also seasonal changes in the relative palatability of evergreen foliage. Long-term changes in possum diets also follow changes in vegetation composition induced by their browsing;4,278 Reduction in possum numbers in podocarp–broadleaf forest significantly altered the diet of the remaining possums; they ate less foliage of common canopy species and more fruits and foliage of uncommon early successional plants.375 Fruits of at least 65 species of native plants are eaten, mostly in proportion to availability.83,97 Entire crops of some species, e.g. kaikomako (Pennantia corymbosa),

2 – Family Phalangeridae

Figure 2.2:  Variation in possum diet with location and time since colonisation.174 Left and centre: The composition of forest vegetation is changed over time by persistent possum browsing on some tree species more than others. The Orongorongo Valley near Wellington has been occupied by possums for much longer than Mapara: their preferred species (k¯amahi, r¯at¯a, five-finger) are still selected out of all proportion to availability: the same process is under way at Mapara. Asterisks mark species at risk or already reduced by browsing. Right: Consequent changes in diet of possums, Orongorongo Valley, resulting from browse-induced extinction of highly palatable plants. (Diagram compiled by M. Oulton.)

may be destroyed in a few days. Compared with birds, however, possums provide little benefit as seed dispersers.435 Buds and flowers may comprise up to 30% of the diet in season.147 Invertebrates were found in 48% of pellets from the Orongorongo Valley,102 mainly in summer and autumn, but contributed 95% of dens located were above ground.96 On Mt. Bryan O’Lynn, Westland, few such sites were available, and >70% of dens were under logs or roots of trees.178 In South I. high country grasslands, 60% of dens were in rocky outcrops.334 In forest, possums generally use 5–10 different dens at any one time, none exclusive to only one possum and, in general, actively defended against others only if occupied.199,297 Males and females use similar types of den sites,178 usually on the periphery of a possum’s nightly range. Possums change to another den on average two nights in three, but sometimes one individual may use the same den for weeks, and some den sites are used much more frequently than others.76,429 After a control operation, female possums may spend more time in dens.427 In forest, dens are not usually shared, except with young, unless density is high and den sites few. An observed den sharing rate of 7% a day was greatly reduced after possum density was reduced.56 On farmland, sharing of dens is more frequent; up to five possums may be found in one hollow willow tree.145

Home ranges. Home-range size is strongly influenced by habitat type. In forest, home ranges are typically around 1–2 ha, but may be much larger for individuals that den in forest and travel to forage on pasture.13,94,174,177,426 Urban possums in Dunedin had an average home range of 3.5 ha;1 possums in fragments of pine forest had average home ranges of 6–12 ha; and average home ranges at dryland sites ranged from 22–60 ha.333,335,437 Males generally have larger home ranges than females, and travel further per night.1,94,174,328,335,437 Home-range size is inversely related to population density,140,303,426 and older individuals tend to have larger home ranges than younger ones.328 Some individuals have been recorded to range over 100–200 ha.335 Possums living on farmland with scattered patches of remnant forest or scrub have two types of ranging behaviour.94 Some have small ranges centred on preferred habitats, such as stream-side willows or swamps, and never venture far out onto farmland; others range up to 1600 m over open pasture and have annual home ranges of up to 60 ha.45 Distinctly bimodal ranges have been recorded for some possums, both by radio-tracking and by trapping.136 Such behaviour may allow possums to take advantage of patches of higher quality or seasonally available foods. Because female young tend to establish home ranges close to, or overlapping, those of their mother, home ranges of females are effectively inherited.134,138 The few juvenile males that stay on their natal range gradually shift away from their mothers over the first 2–3 years after independence to settle, on average, several range lengths away.134,138,215 Areas from which possums have been cleared by control operations have often been likened to ‘sinks’, supposedly attracting possums in from immediately surrounding areas to take advantage of a newly available excess of food and den sites, but there is little evidence to support such an effect.45,303 Survivors adjacent to the controlled zone may shift their home ranges, but only by 200–300 m, and not necessarily in the direction of the controlled zone.136 Few possums moved further than 200–400 m over 1–2  weeks to reach bait stations and poison lines,385 roughly the length of an average home range in similar habitats.94 Large rivers may restrict travel, promoting movement of possums along valleys.51,346 The social organisation of possums appears to be a system of mutual avoidance between co-dominants (older males and females); only the area around dens or den trees is actively defended.110,174,426 The exclusive areas of

2 – Family Phalangeridae

high-ranking males and females are widely overlapped by the ranges of lower ranking individuals,69,174,393 without prompting territorial behaviour.419 Typically, when two possums interact, one is clearly dominant over the other.114,355 Heavier, older animals are usually dominant over smaller, younger ones, and females over males, at least in captivity.29,220 Disruption of sex steroid levels by ovariectomy,220 vaccination against gonadotrophin-releasing hormone,218 or castration250 did not alter established dominance status in groups of captive possums. In males, dominance was associated with higher levels of plasma testosterone during hierarchy formation and during the breeding season.422 Communication. Individual recognition is based primarily on smell, and secondarily on vision.27 Important scent glands are located in the labial, chin, sternal, paracloacal (anal) and pouch regions.251 The sternal and paracloacal glands are larger and more active in males than females.27,36 Development of the sternal gland is related to the onset of sexual maturity, and seasonal variation in activity is closely related to breeding.199 Scent-marking and associated behaviour28 commonly includes rubbing of branches or the bases of tree trunks with the chin or sternal gland;199,432 deposition of secretions from the paracloacal glands (sometimes mixed with urine or faeces); or copious white oil-gland secretion, often produced by animals under attack or disturbed by handling.340,390 The chemical composition of secretions from the paracloacal scent glands varies between individuals, suggesting a potential role in signalling identity and/or status.251,252 Olfactory communication in possums is primarily related to resource protection and mutual avoidance; e.g. scent marks from sternal and paracloacal glands may carry information on social status, location, sex, time of marking, and age.199 Possum vocal signals include at least 22 different sounds.28 There are screeches, grunts, growls, hisses, and chatters (mostly used in aggressive interactions); zookzooks and squeaks (dependent juveniles and pouch young); and shook-shooks and clicks (males during courtship). The shook-shook sound of the male, resembling the call of juveniles, may serve to reduce female aggression.424 Possums can hear sounds between 200 Hz and 39 kHz, and possibly beyond this range.289 They also have acute vision adapted for low light conditions.404 Reproductive behaviour. Wild possums are not monogamous,345,378 and may be polygynous.347,376 Genetic

analysis of male reproductive success found individual males fathered 0–4 offspring in a breeding season. Only ~50% of males successfully fathered offspring, and sequential mating with the same female was uncommon. Male reproductive success was associated with body size and age.67 During the breeding season, older females may be accompanied by and share a den with one, sometimes two, consort males for 30–40 days before oestrus.216,432 Reproductive rates are not reduced by control operations, and may even be enhanced.367 Captive males mated with several females per season,217 and both consort and casual matings were fertile.115 When females were caged together with males and the pouch young removed, the incidence of ovulation significantly increased, an effect attributed to pheromones.109 Male possums of the highest rank, both wild and captive, exclude subordinate males from access to females;219 and female possums may also ‘choose’ dominant sires.250 Heavier females (>3 kg), usually dominant over lighter females, produce more offspring than lighter ones.217 Reproduction and development The timing of the breeding season is controlled by daylength. Changing captive possums from a long- to a short-day photoperiod brings forward the onset of breeding,161 while changing possums from a short- to a longday photoperiod terminates the breeding season.162 Photoperiod and food quantity/quality influence the variation in seasonality of breeding, and their effects are modulated by interactions with factors such as density, bodyweight and, possibly, genetics and plant secondary compounds.91 The testis weights of adults do not vary seasonally, but the epididymes are ~25% heavier at the seasonal peak of conception165 during the breeding season.398 Prostate gland weight increases fourfold just before breeding between mid-February and late March, in response to changes in testosterone levels, probably stimulated by pheromones from oestrous females.381 Adult females are polygamous and polyoestrous. An oestrous cycle lasts 26 days, ~8 days longer than a pregnancy. There is no post-partum oestrus, but if a young dies during the breeding season, oestrus follows after 9–14 days.153 Twins are very rare, e.g. one set in ~8000 females,227 but different-sized young may be found in one pouch, because of (1) accidental cross-fostering of an older young when several females den together, or (2) lactation failing to inhibit oestrus, leading to a second birth ~30 days after the first.144

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Most males mature at 1–2 years old, slightly older than females.164 In established populations in native forest, few females breed as 1-year-olds; in colonising populations or those in exotic forests or on farmland, usually more than half breed as 1-year-olds. Thereafter age has little effect on breeding rate (except at ages >10 years), and >80% of females produce one pouch young each year.324 The probability of breeding declines rapidly as body condition falls below average. In Orongorongo Valley, breeding rate and body condition were both related to an index of food used by possums (fruit-fall of hīnau, Elaeocarpus dentatus), to population density in the current year, and to population density in the previous year. High density in the previous year coupled with low hīnau fruitfall in the current year predicted below average body condition and reduced breeding rate.324 Such assessment and interpretation of body condition in relation to ecological performance suggest that reproduction in possums is consistent with delayed density-dependent effects on fecundity,324 and hence regulated by food supplies.197 Births are recorded in every month of the year, though in most populations they are strongly seasonal.230 The main birth season is autumn (when 80–100% of adult females breed). The median date of autumn births varies from mid-April to early June in different populations, depending on nutrition (reflected in female bodyweights); when female weights are high, breeding is earlier.24 The second and smaller spring birth season is more variable because it is associated with early breeding in the previous autumn, and bodyweight. Females in colonising populations, and in exotic forest or pasture/scrub, breed in spring more often (mean 13%; range 2–33%) than those in established populations in native forest (mean 1%; range 0–3%).174 Spring breeding is not related to latitude (Table 2.4), but to habitat and density, both of which affect female condition. Spring births are also recorded in females which missed the previous autumn breeding, or which have matured since then. Females may breed in both autumn and spring (double-breeders), but only in populations with early ­ autumn breeding, and in above-average condition.174,230 The first young of a double-breeder is weaned and independent at 6 months old, as females do not often suckle two such differently aged young at once. The single young is born weighing 0.2 g, after 17–18  days gestation.398 It has well-developed lungs, upper digestive tract, mouth, forelimbs, and olfactory epithelium, but rudimentary hindlimbs.196 The newborn

possum climbs unaided from the urogenital opening to the pouch, perhaps guided by olfaction, and attaches to a teat, the end of which swells up inside its mouth; it remains permanently attached for ~70 days, then releases the teat for increasing intervals. The relationship between head length and age is linear for ~150 days, and has been used to age young and calculate dates of birth.110 However, growth rates differ both between populations, and within the same population in different years,24,137 which affects the accuracy of age estimates. Weight increases slowly to ~90–110 days of age, then more rapidly, associated with parallel increases in size, weight, and milk production of the suckled mammary gland.100,351 Fur is evident by 90–100 days; eyes open ~10 days later; homeothermy develops at ~110–120 days.164 The young emerge from the pouch at intervals, which gradually increase from 120–140 days old onwards, first to ride on their mother’s back, later as young at foot. Males play no part in the rearing of their young. Most young have left the pouch permanently by ~170 days old, though some continue to suckle for up to 240 days. The young gradually become more independent, and from 240 to 270  days may be found alone but within their mother’s home range, denning with their mother or alone.432 The teeth erupt in a predictable sequence helpful for estimating the age of very young possums.231 More males are born than females.134 However, female possums, at least in Australia, may adjust the sex ratio of their offspring in response to local conditions, producing heavily male-biased sex ratios in some populations.215 The survival of pouch young is variable but equal between sexes, and lower in spring-born than autumn-born cohorts.24,393 Females breeding for the first time, or >10 years old, or of less than average bodyweight, are less successful at raising young.24,324 Generally, survival of pouch young is high, but varies between localities, habitats, and populations with differing maternal age and condition.24,69,187,324 For example, in Orongorongo ­Valley, average survival to independence of young born in 1966–75 was 58%,24 but 78% near Hobart, Tasmania.187 The hope of achieving biological control of possums via manipulation of fertility has stimulated an enormous increase in knowledge of possum reproductive physiology, lactation, and development of young.89,244,363 Experimental analysis of possum biology was greatly enhanced by research into improved husbandry protocols, procedures, and detailed analyses of responses to stress and adaptation to captivity.217,249 Reliable techniques were

2 – Family Phalangeridae

Table 2.4:  Contribution of spring births to total breeding success of possums living in Australia and New Zealand. Latitude in decimal degrees.

Latitude (°S)

Total births all year

% of births in Sep–Nov

Australia Jabiluka, NT

Reference 230

12.63

36

19.5

Brisbane, QLD

27.55

43

18.6

Bonalbo, NSW

28.73

27

0

Clouds Ck, NSW

30.08

45

6.6

Tutanning, WA

32.60

27

33.3

Sydney, NSW

33.88

28

25.0

Yass, NSW

34.85

29

10.3

Adelaide, SA

34.93

121

14.1

Canberra, ACT

35.28

113

25.6

Urana, NSW

35.33

54

9.4

Kameruka, NSW

36.75

37

10.8

Beaufort, VIC

37.43

44

29.6

Healesville, VIC

37.65

20

30.0

Geeveston, TAS

43.10

199

0

Silverdale

36.62

58

15.5

393

Tokoroa

38.25

140

16.4

69

New Zealand

Bridge Pa

39.90

112

16.0

41

Kapiti I.

40.85

110

1.0

100

Whareama

40.90

272

24.3

100

Orongorongo Valley

41.35

394

0.8

24

Mt Misery

41.92

46

0

75

Banks Peninsula

42.53

136

13.2

164

Menzies Bay

42.65

42

2.4

397

Ashley SF

43.22

115

2.6

407

developed to induce superovulation, artificial insemination, and gamete maturation.108,260 Population dynamics Density. In 2009, the total number of possums in New Zealand was estimated at ~30 million.412 In podocarp– broadleaf forest, density averaged ~10–12 per ha (range 7–24 per ha);20,80,110,135,328 ~1–3 per ha in pine plantations;69,141,407,426 ~0.5–5 per ha in southern beech (Fuscospora) forest;75,303,369 less than 1 per ha in drylands; and ~1–9 per ha on farmland,155,207,216,393 although reaching ~5 per ha in streamside willows and 10 per ha in a scrub-filled swamp.45 The main biotic and abiotic

factors influencing possum abundance have recently been identified.156 Density varies with forest association and elevation. In Westland, forest-pasture margins supported ~25 possums per /ha, lower slopes 10 per ha, upper slopes 5–6 per ha, and mountain tops (above 800 m) only 2 per ha.80 On Mt Misery, Nelson Lakes NP, the lower areas of mixed ­podocarp-beech forest had ~0.9 possums per ha compared with only 0.3 per ha in pure beech forest above 1400 m, and none above the treeline.75 Numbers are usually highest in February–May (with the seasonal influx of newly independent young) and lowest in September– October (due to winter mortality).42

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Among sites in mixed podocarp–broadleaf forest, density was unrelated to latitude. The highest accurately measured possum densities (>15.0 per ha) have all been at forest margins within 250 m of pasture.45,80,136 Possums favour such areas because the diversity and biomass of understorey species is greater there, particularly if livestock are excluded.278,290 Colonisation of new areas follows a predictable pattern, well described in the Taramakau Valley,14 in ­Westland NP and in South Westland.306,370 There is an initial slow but steady increase in numbers, a relatively short-lived irruption to a peak population, then a sharp, often drastic, decline to lower and more stable levels. Peak densities (assessed from pellet counts) may be more than twice those of post-peak populations. Severe damage to vegetation is evident at peak population levels, but some recovery is possible after the subsequent decline, particularly if ungulates are absent.306,370 Pre-peak, peak, and post-peak populations differ in many characteristics; e.g. populations in decline have lower fecundity, increased average age, an excess of females, later sexual maturity, cessation of spring breeding, reduction of adult bodyweight and growth rate, and lower fat reserves.158,370 These effects are partially reversed by density reduction after trapping or poisoning.98,176,367,374 Possum populations have been monitored annually over many years in two areas: the Pararaki catchment in southern Wairarapa, and the Orongorongo Valley near Wellington. Analysis of population trends at Pararaki supports an ‘irruptive fluctuation’ type of model explaining the coupled dynamics of possums and their food supply. Segments of the post-1965 Pararaki data can be interpreted as varying around an equilibrium, although this level may have declined over time.85 By contrast, possums have lived in the Orongorongo area since 1893, and the present population shows only weak evidence of an initial irruption and subsequent decline. Over a 30-year period, there has been little or no long-term trend in density of possums there, only a short-term (4-year) cycle in possum numbers.135,139 Between 1967 and 1998 the population density fluctuated between 6.5 and 13.7 per ha (mean 9.8). Major decreases from the mean in 1971–72, 1977 and 1995–96, associated with extreme weather patterns, were in each case followed by an abrupt correction. In statistical terms, a population is ‘regulated’ if it displays a long-term stationary distribution of population size. The Orongorongo Valley possum population meets this criterion, at least on a long-term (>10-year) timescale,

via a delayed density dependent link between reproductive success and food supply.139 The natural behaviour of possum populations in unmanaged areas that have had possums for decades is therefore probably a modest annual fluctuation around the mean. Dispersal. About 20–30% of possums disperse from their natal areas, either as juveniles at 8–12 months old, or as young adults at 18–24 months.51,92 In the Orongorongo Valley, young of the year disperse mainly between J­ anuary and May, but those dispersing in their second year are more likely to move between September and February; thus, dispersal may be observed almost year-round. Dispersing possums can cover long distances in a short time, up to 3 km in a night, and 10 km in a week, for an average total movement of ~5 km.51,167 They also may make several moves before finally settling in a new area; e.g. one juvenile female in the central King Country moved five times in 72 days.105 Dispersing female possums tend to move further than males (the two longest recorded moves, 32 and 41  km, were both by females) and make more moves before settling.138 So, although females disperse much less frequently than males, they may be disproportionately important in spreading bTB. Control reduces but does not eliminate juvenile dispersal, because dispersal of possums from their natal areas is independent of density. After a control operation that killed more than 90% of possums, the absolute number of juvenile possums that dispersed decreased, but the proportion that dispersed remained unchanged.101 The distances moved by juveniles dispersing from the controlled population also did not change significantly, so that, even after control, some juvenile possums are still likely to disperse through areas of reduced possum density (buffer zones) established for bTB management. ­Juveniles whose mothers are removed do not necessarily disperse, but may expand their home ranges.32 There is a strong bias towards male dispersal; in Orongorongo Valley, 72% of newly independent females, but only 28% of males, settled in their natal area, and even those males tended to shift their ranges away from their natal area in time.74 The sex ratio of possums reinvading a depopulated area in the Orongorongo Valley was 1.7M:1F; new individuals arrived at a relatively constant rate, with no apparent seasonal influx.92 The consequences of malebiased dispersal are (1) an excess of males in colonising or reinvading populations; and (2) the establishment of local groups of closely related females.74,176,212,394

2 – Family Phalangeridae

Possums are also capable of homing over distances significantly greater than their normal nightly movements. In a translocation experiment, four possums moved 4 km from the same location on Manawatu farmland all returned to their original home areas within 3–19 days.99 Sex ratio. Sex ratios generally favour males early in life and females later.42,81 Small samples probably overestimate the proportion of males, which are more active and range further, and are hence more often caught.81 Also, colonising or reinvading populations can initially be male-biased, but, since females increasingly outnumber males at ages ≥ 7 years, established populations gradually revert to parity or an excess of females. However, sex ratio may not be constant through time even within a single undisturbed population. For example, the ratio in the long-established population in the Orongorongo Valley shifted from near parity before 1978 to distinctly malebiased (57% males) in 1980–94.134 Age determination. Usually done from tooth eruption sequence in juveniles231 and molar toothwear in adults,227,432 validated on known-age skulls.106 Accurate age is determined by counting annual rings in lower third molar cementum.70 Maximum longevity of known age free-living possums is 13 years for males and 14 years for females,42 although higher numbers of annual rings in teeth have been found in carcasses.100 Productivity. The mortality of pouch young between birth and independence is often only 10–20% in pine forest, mixed scrub, and bush patches,164,393,407 but in podocarp–broadleaf forest, it ranges from 70%,135,213 mostly at ~3–4 months of age. Between first pouch emergence at 4–5 months and 2 years of age, few independent young survive.135 Of 116 pouch young born in Orongorongo Valley in 1979 and 1980, 39% died in the pouch and 38% disappeared (and almost certainly died) between pouch emergence and 9 months of age; of the remaining 23%, 37% died on or near their natal area and 22% dispersed.420 Thus, of the original 116 young, only 11 survived to 2 years of age on their natal area. In forest a female, on average, weans 1.5 young by 3 years of age; in pasture/scrub or colonising populations 2.0 young, or more if double-breeding is taken into account.174 The Orongorongo Valley population produces

only 0.4 independent young per female per year compared with 1.2 per female per year in Canberra, Australia.43 Possums were experimentally removed from two 6-ha areas of forest near Auckland, and their subsequent reestablishment was monitored. Around 80% of females bred in the original populations, but 100% of females bred in the recovering populations, and a greater proportion of pouch young survived to weaning. After 2 years, possum abundance was 32–56% of that in the same season before the removal.213 In mixed conifer–broadleaf forest, the exponential rate of population growth during 2.5 years after being reduced to near-zero density was 0.59.367 However, the maximum population growth rate has been estimated at 0.77 per year, which suggests that >54% of individuals would have to be removed each year to eliminate a population.193 Annual adult natural mortalities average 15–30%,73,353 generally lowest at 2–4 years, then increasing with age, but the further life expectancy of 3–4-year-old possums is still ~5 years.42 Occasional periods of severe mortality may be associated with sustained bad weather; e.g. ~40% of adults and all but one pouch young died in Orongorongo Valley during a particularly wet winter in 1977.425 The annual rate of survival of Orongorongo possums varies strongly with age, and is higher in females. Annual survival peaks at ~90% for females aged 2–5 years old, compared with 80% for similar-aged males.135 The dynamics of possum populations have been modelled in relation to browsing damage,127 effects of control,193,321 controlled harvesting of fur for maximum sustainable yield,16 and bTB control.15,54,159,326,330 Predators, parasites and diseases Predators. Feral cats are the most frequent predators of possums. In Orongorongo Valley, possum hair or bones were found in up to 38% of cat scats in winter and spring, and newly independent young are often taken in spring.152 Young possums may be killed occasionally by stoats, moreporks, or Australasian harriers/kahu (Circus approximans). Possums are frequently run over by vehicles (Fig. 0.3), with unknown consequences for local populations.44,342 The significance of natural predation in the population dynamics of possums in New Zealand is unknown, but is probably much less than that of control or harvesting. Fur trade. During a period of strong demand for possum skins in 1978–82, >2 million skins per year were exported;

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possums became scarce in many accessible areas; and the average size of skins offered for sale declined.73 After the market for pelts collapsed in the late 1980s, largely due to the anti-fur movement overseas, the numbers of possums harvested annually fell to ~250  000 per year in 1996–98.418 Since 2000 the development of mixed possum fur/wool fibres has renewed interest in possums as a ­commercial product, pushed the price of plucked fur (free  of the  skin) to >NZ$100 per kilogram, and stimulated renewed harvesting of wild possums.221 On average 18 possums yield 1 kg of loose fur. In 2014 the possum fur industry generated retail sales of possum-related garments of between NZ$100 and NZ$150 million from a harvest of ~2 million possums.270 Ectoparasites. Mites dominate the ectoparasite fauna of New Zealand possums. Atellana papilio was found on all of 59 possums from Banks Peninsula,364 and on 46% of 125 possums from central Otago, 42% of which also harboured Trichosurolaelaps crassipes and 50% had Petrogalochirus dycei.39 Of a total of 84 pelts examined in detail from nine sites in the North and South islands, A. papilio was found on 98%, P. dycei on 93%, Murichirus anabiotus on 93%, and T. crassipes on 99%.65 The follicle mite, Marsupiopius trichosuri, was found only on skins from Kawau I. and Orongorongo Valley. An unidentified lung mite has been found in lung washings from possums.182 Possums infested with fur mites often have patches of skin irritation and fur loss on the lower back and rump (rumpiness)318, although other factors also contribute to rumpwear.195 Heavy mite burdens are generally found on possums in poor condition or in high-density populations where sharing of nest sites is common. Mites occasionally cause allergic reactions in possum trappers.66 Nymphs and larvae of the cattle tick, Haemaphysalis longicornis, were found engorged on some pelts from Northland. Endoparasites. New Zealand possums carry relatively few endoparasites, including only one specific tapeworm, Bertiella trichosuri, two specific nematodes of the small intestine, Parastrongyloides trichosuri and Paraustrostrongylus trichosuri, and a specific coccidian, Eimeria sp.284,311,319 They may also be infected with the protozoans Giardia intestinalis, Cryptosporidium parvum62 and Toxoplasma gondii,86 liver fluke (Fasciola hepatica),107,319 and a range of intestinal strongyloid nematodes from livestock and rabbits.93 However, the strains of Giardia and Cryptosporidium carried by possums may not be zoonotic

species.185 Although possums can be experimentally infected with the dog roundworm Toxocara canis,365 infection has not been recorded in free-living possums. Early surveys found Bertiella trichosuri in 19–31% of possums in the North I., and 0–41% in the South I.319 More recent surveys93 have confirmed its generally low prevalence and widespread but patchy distribution, including Kawau and Chatham islands. Infested females had lower mesenteric fat reserves and slightly reduced fecundity compared with non-infested females.408 The life cycle of B. trichosuri has not been fully determined, but possums living in forest and on pasture are infested to about the same extent. Parastrongyloides trichosuri is common throughout the North I.93 and in coastal Southland and western Otago, but not on either Stewart or Chatham I. Naïve, free-living possums in the north-west South I. were artificially infected to assess the potential of the this nematode as a vector for biological control; infection spread over ~6000 ha in the 2.5 years after infection.104 Paraustrostrongylus trichosuri is also common throughout the North I., but more patchily distributed and less prevalent than P. trichosuri.93 In the South I., a single record from the Longwood Range is suspect, as subsequent surveys failed to record its presence there.103 It was not recorded on any of the offshore islands sampled. Other nematodes recorded include Trichostrongylus colubriformis, T. axei, T. retortaeformis and T. vitrinus.93,356 Anthelmintic dosing trials suggest nematode infections usually have little effect on possum bodyweight and breeding.100,402 Leptospirosis (Leptospira interrogans serovar balcanica). Common and widespread in the North I. (in up to 80% of adults), but absent in Westland, perhaps because most of the original releases there came from balcanica-free ­Tasmania. Infection of possums with other serovars (­ballum, copenhagenii, pomona, tarassovi) is rare, and balcanica is apparently not readily transmitted to humans, even high-risk groups such as possum trappers.33 The effects of balcanica infection on possums appear slight.319 Leptospirosis is transmitted between possums only during affiliative or sexual interactions, more often with increasing frequency of mating contacts between possums,325 but not during agonistic interactions that involve equally close contact.115 Bovine tuberculosis, bTB (Mycobacterium bovis). First confirmed in possums in New Zealand in 1967, bTB became widespread by the turn of the century.10,173

2 – Family Phalangeridae

Possums are the principal wildlife maintenance host for bTB in New Zealand, and their transmission of the disease to livestock is a matter of major economic significance.9,77 Typically, 1–10%, but occasionally up to 60%, of possums in a bTB-infected population show macroscopic lesions. Most infected possums die within 3–6  months,273,274,323 but a few take much longer.273 Male possums experimentally infected with bTB survived longer on average than similarly treated females; some individual males may therefore contribute disproportionately to the spread of bTB.336 Increased mortality caused by bTB does not necessarily affect population density, because it may be balanced by compensatory recruitment.11 Prevalence of bTB in possum populations is usually low (1–5%) at the regional scale, but can be as high as 60% in localised hotspots.274 How bTB is transmitted between possums is unknown, but appears to be related to direct contact, e.g. mating, fighting or feeding on infected carrion.274 However, direct contact between possums is infrequent, and usually brief, except in shared dens.214 Possums infect livestock by environmental contamination and directly, mainly when inquisitive stock encounter terminally ill or recently dead infected possums. Buffer zones, in which possums are reduced to low density within 3–5 km of the interface between forest and pasture, can reduce the probability of possums infecting cattle.51,274 Oral vaccines have also been developed to reduce bTB prevalence in wild possums;48,283,391,392 but management has focused increasingly on lethal control to reduce possum densities to below the level at which bTB dies out for lack of contacts.6,49,274 Spatial population modelling predicts that reducing possums to low density for 5 years will have a 95% chance of locally eradicating bTB,326 but longer term control may be necessary to prevent reinfection of the possum population by other wildlife hosts.18,413 Modelling also suggests that nation-wide eradication of bTB is feasible,192 and this has been adopted as the objective of the National Pest Management Strategy.198,241 Eradication efforts are aided by advances in surveillance methods to detect bTB in wildlife and/or confirm its eradication from an area.6,7,170,282 The recorded distribution of bTB in possum populations continued to grow between 1994 and 2012, mainly due to improved detection. No expansion has been recorded since then, and bTB has been eradicated from some areas;241 see Fig. 2.3. Scavenging of infected possum carcasses by predators, particularly ferrets, is an important route of transmission

of bTB to predators.53,55 Mycobacterium vaccae, M. avium and M. fortuitum have also been recorded in New Z ­ ealand possums. Other diseases. Periodontal disease (cause unknown) may be found in the lower jaw of 250 frosty days a year, such as the upland Southern Alps and parts of the central North I. plateau, and in areas with >2500 mm of rain a year, such as Fiordland. Habitat Habitat use by hedgehogs is generally related to the availability of food and dry nest sites, so may therefore vary with season. Hedgehogs are abundant on lowland and coastal farmland and in sand dune country, e.g. in Manawatu and Northland, where frosts are few and mild, especially in dairy country, where invertebrate foods are plentiful in long pasture. Lowland stream and river sides are favoured habitats. Cities and suburbs support dense populations of hedgehogs, because invertebrates and dry hibernacula are available, as well as extra food purposely or accidentally provided by householders. They were the most widely distributed and frequently detected small pest mammals recorded in surveys both of Waikato farmland119 and of green-space habitats within Hamilton.81 Hedgehogs are less common in dry central and upland areas where frosts are harder. The lack of dry nest sites keeps hedgehogs out of rainforests, but some survive in very wet broadleaf–podocarp forest of the Ruahine, ­Tararua and Rimutaka ranges, and in beech forests of the South I. They were common within indigenous and exotic forests in Pureora Forest Park (FP),67 and favoured ­broadleaf–podocarp forest and upland shrub–grasslands at Boundary Stream.6 In the braided river systems of the central South I., most monitored hedgehogs used the grassier vegetated habitat types where their preferred foods are most abundant. Some individuals focussed their foraging out on the dry river beds where at-risk native birds build their nests.62,100,106 Food Hedgehogs are mainly insectivorous, but will eat any animal substance and even some plant material. They eat ~160 g each per day,127 mostly invertebrates. Innes et al.55 estimated that the average total biomass of invertebrates eaten by introduced mammals in North I. podocarp– broadleaf forest is ~740 g/ha/night, of which 660 g/ha/ night is taken by hedgehogs – >8 times more than the toll exerted by five other pest mammals put together. On pasture near Christchurch, hedgehogs ate large numbers of grass grub (Costelytra zealandica) beetles and porina moth (Wiseana cervinta) larvae.21,39

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Figure 3.1:  Distribution and relative abundance of hedgehogs in New Zealand in 1972.15 No more recent survey is available.

Diets reported by different studies reflect local and seasonal availabilities,63 but beetles are important food in most studies. In suburban areas and lowland farms, hedgehogs eat mainly slugs, snails, and a great variety of ground insects and larvae.12 Earthworms are commonly eaten in pasture, but rarely in forest or drylands, where wētā and grasshoppers are more important. Earwigs and lepidopteran larvae are eaten in large numbers where available.6,88

Hedgehogs also feed on mice, lizards, frogs, the eggs and chicks of ground-nesting birds and domestic fowl, and they scavenge carrion, e.g. rabbit and sheep carcasses in the Mackenzie Basin.88 Remains of native skinks were found in 21% of hedgehog guts from Macraes Flat in Otago,115,122 skinks or geckos in 6% of guts from the Mackenzie Basin,61,88and Suter’s skink (Oligosoma suteri) in hedgehog scats on Motutapu I.66 Skinks are 3–4 times more likely to be eaten by female

3 – Family Erinaceidae

hedgehogs, especially during the peak energetic demands of breeding.61,115 Eggshell remains have been found in 2–4% of gut samples, and feathers in 2–10% of guts and droppings collected from a range of habitats.60,88 The frequency of occurrence of eggshells in guts or faeces may under-­ represent the real proportion of eggs in hedgehog diet, because, after breaking into eggs of banded dotterels and black-fronted terns, hedgehogs were observed to carefully lick out the contents, and avoid chewing the entire egg.2,103,125 Hedgehogs living both in New Zealand and overseas select energy-rich fruit quite deliberately; fruits such as cherries and rose hips are eaten frequently and in considerable numbers when available.52,63 Social organisation and behaviour Activity. Hedgehogs are largely nocturnal. They emerge from their nests at dusk and are most active early in the evening. Both captive21,71 and wild14 hedgehogs concentrated their activities in the 2–3 h after sunset, and again 8–9 h after sunset, with less activity between these times. All 34 visits by hedgehogs to nests of ground-nesting birds in the Mackenzie Basin were recorded between 2000  h and 0500 h.105 Of 871 visits by hedgehogs to ­Waikato farmland bait stations, 856 were at night and 15  by day.119 Hedgehogs seen active in daylight may be searching for water during droughts, in poor health or too underweight to hibernate. Hedgehogs concentrate their feeding activity on any temporary locally abundant food.91 An adult male trapped in the Mackenzie Basin had 293 Hemiandrus wētā legs in its gut, and another male living on Canterbury pasture habitat had consumed 424 grass grub beetles in a single feeding bout.21,61 Hedgehogs can learn the location of a novel food source and alter their foraging behaviour to visit food-rich areas.24 Trials with chemically marked eggs in artificial nests identified one individual as a repeat predator of different nests.59 Hedgehogs are excellent swimmers and climbers.102 Marked individuals with spools of thread attached to their spines to monitor habitat use left a thread trail across stretches of marshland and open water up to 3 m wide.60,62 Dispersion. Hedgehogs are normally solitary, except during brief mating encounters and before dispersal, when they still depend on their mothers. They do not defend territories, and their home ranges often overlap,20,88,91 although

they keep a fairly constant distance from one another even during local aggregations at a rich source of food.24 Most estimates of hedgehog home-range size102 fall between 2 ha and 50 ha, rarely to >100 ha (Table 3.2). Some of this variation may be influenced by field and analytical methods,48 but home ranges of males are typically 2–3 times larger than, and may overlap with, those of females, and home ranges of both sexes are larger in spring and summer than in autumn and winter. Although hedgehogs are not territorial, access to food may depend on a social hierarchy favouring heavier females.23,32,73 At Lower Hutt, many hedgehogs spent the colder months in suburban gardens, but during summer some shifted to a local golf course.14 Some parts of the golf course were never visited by hedgehogs, while other paths were well trodden by many animals to form hedgehog ‘roads’; 95% of marked hedgehogs were recaptured within 800 m of their point of release. Within its home range, a hedgehog will typically use intensively a central core area, and share parts of the rest with 1–5 other hedgehogs.6,88 Hedgehogs can travel long distances; one radiotracked hedgehog moved 10 km along the Ohau River between April and October 1998,88 and 16 of 65 marked hedgehogs in the Mackenzie Basin travelled more than  5  km, maximum 12 km, over 26 months.89 In Hawkes Bay, the overnight routes taken by seven radiotagged male hedgehogs averaged 908 m per night (range 477–2264 m).6 Shanahan et al.106 found that hedgehogs often used up the full 900 m of thread in a spool backpack in one night. Dens. Hedgehog dens are used (1) as daytime retreats during active seasons (‘summer nests or day nests’); (2) for breeding females and their young (‘breeding nests’); and (3) for hibernation or aestivation (‘hibernacula’ or ‘winter nests’).102 Hedgehogs typically construct nests on dry, well-drained sites where they can form an ellipsoidal chamber in loose detritus or vegetation.6,79,88,91,102 Nests are often located under or against some form of support such as fallen logs, bushes or buildings, or under large shrubs, tussocks, tree roots, or piles of leaf litter or compost. Winter nests are larger and better constructed than summer nests. In warm weather hedgehogs may simply sleep under cover without making a nest, or even in the open. Hedgehogs will also nest in crevices, e.g. between rocks and in rabbit burrows. In the rabbit-prone Mackenzie Basin, Moss88 found 33–50% of nests in rabbit

83

37.9 11.4

Adult males Adult females Adult males Adult females

All year, 18 months

Spring–late autumn

Summer–autumn Spring–summer Spring–summer Late summer– autumn

Pasture and pine plantations

Pasture and native bush

Mixed forest, scrubland, grassland

Scrub, willow and grassland adjacent to braided rivers

MCP = minimum convex polygons, n = number of individuals tracked.

Adult males

43.6

94.0

29.3

4.2

9.3

Juvenile females

Adult females

2.3

Juvenile males

9.6

3.6

Adult females

Adult males

2.5

Adult males

18.7

2.0

Juvenile females Adults, both sexes

1.9

Juvenile males

All year, 2 years

2.8

Adult females

Golf course

2.4

Adult males

Mainly summers, over 2.5 years

Pasture

Age, sex

Season

Mean homerange estimate (ha)

Habitat

Table 3.2:  Estimates of hedgehog home ranges in New Zealand.

5.6–18.3

24.2–49.6

17.3–73.8

16.6–196.9

9.4–46.9

3.0–5.1

7.4–12.7

1.4–4.9

0.5–4.9

1.0–6.5

0.8–4.8

5.1–25.9

Range (ha)

100% convex polygons

95% MCP

95% MCP

95% MCP

Convex polygons

100% convex polygons

Convex polygons

Method

4

4

3

11

7

3

3

3

3

10

4

10

3

3

7

7

n

88 (Concave polygons, ellipse estimates, range span and core areas also available)

6 (50% and 95% Anderson estimates and core areas also available)

42 (80% and 90% kernel estimates also available)

91

14

20

Reference

84 The Handbook of New Zealand Mammals

3 – Family Erinaceidae

burrows, depending on season. In some habitats, availability of dry nest sites may limit the distribution of hedgehogs.85,91,102 Several nests are constructed throughout a home range. Summer nests are usually used only once, but the best ones are used repeatedly, over consecutive days, or sporadically.6,79,88 Nests are almost always occupied by a single animal, but Moss88 reported finding one nest occupied by two individuals at the same time, and nests may be used by more than one hedgehog at different times.46,98 Disturbance of occupied nests (e.g. by human investigators) can cause hedgehogs to move elsewhere.79,88 Hibernation and torpor. Hedgehogs conserve energy during periods of torpor. In daily torpor, metabolic rate falls by ~70%, although body temperature remains above ~30°C. In seasonal torpor (hibernation), metabolic rate is reduced by ~95%, and body temperature falls to within a few degrees of ambient temperature.41 While hibernating, the heart slows to ~20 beats/min, and breathing becomes intermittent, e.g. 40 or 50 rapid breaths, then none for up to an hour. If the environmental temperature approaches 0°C, a hedgehog can increase its metabolic rate to maintain its body temperature above 1°C.72 While preparing for hibernation, winter fat is laid down first on the belly, then the back, and lastly around the kidneys and the gut lining. During hibernation, the fat is used up in the reverse order; the subcutaneous fat, which provides insulation, is the last to be used.14 The minimum pre-hibernation bodyweight required to ensure survival, the average loss of weight during hibernation, and the duration of the main hibernation period, all vary with latitude. Brockie17 estimated that juvenile North I. hedgehogs must attain a weight of at least 300 g before they can survive hibernation. Fat stores in hedgehogs of that size constitute 1–2% of bodyweight,123 and are enough to support them in torpor for at least 3 months at 5°C. If adult hedgehogs did not enter torpor in cold weather, their body fat reserves would be depleted within 1 day, whereas in torpor, they may last for over 100 days.123 Even so, hibernation is very hazardous for hedgehogs; near London during the 1960s, 65% of juveniles, mostly the smaller ones, died during their first winter.84 In ­Finland, adult females lost 30% of their pre-hibernation bodyweight over 198 days of hibernation, compared with a mean loss of 17% over 149 days in Ireland.46,58 New Zealand hedgehogs begin to hibernate when mean earth temperatures reach 10–11°C. The proportion

of the population hibernating depends on the severity of the winter. In warm and relatively frost-free areas like Northland, few hedgehogs hibernate, and then only for short periods.14,79 In Palmerston North, southern Hawkes Bay and Wellington, hibernation extends from June or July to about mid-September.14,91 In the Mackenzie Basin during the relatively mild winter of 1998, hedgehogs hibernated between mid-April and early September.88 Hedgehogs are active, and so vulnerable to trapping, every few days during winter.102 Even at Pureora during the 1980s, when ground frosts were recorded for 87 days per year on average, capture rate was still 0.05 hedgehogs C/100TN in winter (cf. 1.76 C/100TN in summer).67 Males emerge from and enter into hibernation several weeks earlier than females.92 ‘Self-anointing’ and reproductive behaviour. Hedgehogs occasionally froth at the mouth and plaster the spittle on their spines. Newly independent young are 4–5 times more likely than adults to self-anoint, and males more likely than females. In all adults it is more likely during the summer, although there is no direct correlation with the breeding season.29 Of 929 wild hedgehogs examined in New Zealand, 19 bore signs of recent ‘self-anointing’. The spittle thrown on to the back has a pungent smell which could have some unidentified signalling function.10 Reproduction and development Courting behaviour includes ‘cartwheeling’, in which a male circles a female for long periods and attempts to bite her feet. Sometimes the pair attract the attention of another male, which may join in. Hedgehogs are completely promiscuous; there is no pair-bonding and no further contact between males and females after mating. Females will accept several males, and genetic evidence has confirmed multiple paternity within a single litter.56,80 Ovulation is not induced by copulation, and female hedgehogs have a succession of oestrous cycles throughout the breeding season. There is no post-partum oestrus.30 The reproductive organs of both sexes regress during hibernation, but enlarge again in early spring. Hedgehogs collected in New Zealand during September have large accessory glands in males, and sperm in the vaginas of some females, implying that breeding starts as soon as the animals emerge from hibernation. European estimates of the age at sexual maturity of wild hedgehogs range from 9 to 11 months.102 On Uist, off the west coast of Scotland,

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two-thirds of females monitored attempted breeding at 1 year of age, and the remainder 1 year later.56 The breeding season is prolonged, especially in northern parts of the country.126 Females in advanced pregnancy have been found at Kaitaia during August; in such warm areas, late litters may be the second brood of the season for some females. Although second litters have never been confirmed in New Zealand, in Scotland 81% of females attempted a second litter within a single breeding season.56 Near Wellington, hedgehogs mate from September onwards. Early litters are born in late November and December, and late litters through to February or even May.11 In the Mackenzie Basin, pregnant females were caught from early November to January,31 and a pregnant female was found in late March in central Otago.60 The gestation period is 31–35 days.53 North I. hedgehogs carry 4–7 embryos (mean 4.4), but with high juvenile mortality, as one study recorded an average of only 2.7 young per nest.12 The young weigh 15–21 g at birth, and are blind and spineless, but a first coat of white spines appears within a day as oedematous skin contracts. A second set of darker spines grows within 36 h. The youngsters can roll up after 11 days, and their eyes open at 14 days. Young hedgehogs first accompany their mother from the nest at 3–4 weeks, and become fully independent at 6–7 weeks. Their deciduous teeth are replaced at ~1–2 months. If disturbed during the first 5 days after giving birth, the mother may abandon or even eat the young. Population dynamics Density. There are few reliable estimates of hedgehog density for New Zealand habitats. Most estimates of local population sizes have been based on the minimum numbers of animals encountered during a prolonged study period, not the number present at any one time. For example, Parkes91 marked 150 individuals on 16 ha of dairy farm in the Manawatu over 17 months, and Brockie14 marked 207 on a 56-ha golf course at Lower Hutt over 2 years. More robust recent estimates of hedgehog densities in Europe range from 0.04–0.37 ­ per ha.33,56,101 Relative indices confirm that hedgehogs can be very common. Along river and lake margins in the Mackenzie Basin, they were caught at rates of up to 2.04 C/100TN, more than any other predators,65 but not on islands in braided rivers.93 Mean capture rates in different forest

types at Pureora FP ranged from 0.10 (in logged podocarp) and 1.51 (unlogged podocarp) to 2.02 (older exotics) hedgehogs C/100TN.67 At Trounson Kauri Park, Fenn traps set in mixed kauri and broadleaf forest caught up to 1.3 hedgehogs C/100TN.51 Local aggregations can be remarkable. In Trounson Kauri Park (400 ha) 761 hedgehogs were caught between August 1996 and July 1999;28 400 in 2 years within 1.5 km of New Zealand dotterel (Charadrius obscurus) nests in Northland;95 >2000 in 3 years from 2100 ha at Macraes Flat, N. Otago.99 Hedgehog populations include both resident animals, which may live for several years in the same area, and transients. The transients are mainly young adults, especially young males, caught and marked once in an area but never seen again; they may account for 22% of the population in spring, falling to 8% in winter.14 Age determination. Young hedgehogs tend to have darker spines which become paler as they age; juveniles can be distinguished from adults using a combination of measurements of hind foot, jaw and overall body length.45 Ages of dead hedgehogs can be determined by sectioning the teeth and lower jaw bone and counting annual growth layers, which are correlated with changes in growth rate during and after hibernation.54,84 Survival. Mortality in hedgehogs is generally high in juveniles, low between 1 and 4 years, then rapidly increasing in older animals. Early estimates of average lifespan in New Zealand range between 2–3 years;14,91 overseas, wild individuals can live to age 9.45 Sex ratios in population surveys become male-biased over time, suggesting that the demands of rearing young can limit female survival.56,118 Road deaths. In New Zealand, hedgehogs are more frequently killed on the road than are other common introduced small mammals. A survey repeated along the same 1600 km of North I. highways in 1984, 1994 and 2005 detected a possible irruption in numbers of hedgehogs in 1988–89, followed by an 82% decline (Fig. 0.3, p. xxv) in their numbers between 1994 and 2005.18 The number of hedgehogs killed on the road varied markedly with locality and season. They were most often run over near bridges across drains, streams, and rivers, or where traffic was highest in the suburbs of cities and towns, and less often during winter hibernation.

3 – Family Erinaceidae

Predators, parasites and diseases Adult hedgehogs are well protected against most predators except feral pigs. Stoats and harrier hawks (Circus approximans) scavenge dead hedgehogs;22,69 stoats and weka may take nestlings. Ferrets and cats kill or scavenge hedgehogs occasionally. Five studies in pastoral habitats in Otago and Southland reported remains of hedgehogs in ferret guts at frequencies of up to 8.4%.96,109 In the Mackenzie Basin, hedgehog remains were found in 1 of 45 feral cat guts93, 3 of 358 cat scats, and 0 of 27 stoat scats.94 Parasites and infections carried by hedgehogs in New Zealand are listed in Table 3.3. Hedgehogs are considered a spillover host, rather than a maintenance host, of bovine tuberculosis (bTB).42,74 Yersiniosis, an important disease of livestock overseas, was not isolated from any of 202 hedgehogs investigated in New Zealand.4,43 Mycobacterium avium subsp. paratuberculosis, the cause of Johne’s disease, an enteric inflammatory infection in farmed stock, was found in 36% of hedgehogs from three South I. farms with a history of the disease, implying that hedgehogs may both host and spread the disease.90 The skin and the nasal cavities of many hedgehogs (~86%) support a natural reservoir of penicillin-resistant strains of Staphylococcus, which thrive in the presence of the penicillin-producing hedgehog ringworm fungus, Trichophyton mentagrophytes var. erinacei.112 Of 31 novobiocin-resistant, coagulase-negative strains of Staphylococcus isolated from hedgehogs,25 13 resembled S. xylosus, 10 resembled S. sciuri, and eight did not resemble any previously described species. The pest status of hedgehogs in New Zealand has not deterred public interest in ‘animal rescue’.9 Specialist ‘hedgehog hospitals’ have been set up (at least two in Auckland and one in Dunedin) and veterinarians are often asked to treat injured or unwell hedgehogs. Most rehabilitated hedgehogs released from British hedgehog hospitals behaved normally and survived well in the wild.86 Attempts have also been made to export hedgehogs from New Zealand for the American pet market. In 1994, a shipment of 120 hedgehogs sent from Rotorua to wildlife parks and zoos in the USA was refused entry on the grounds that they may carry bTB, so they were returned to New Zealand apparently none the worse for their travels.9 Adaptation to New Zealand conditions When hedgehogs first arrived in New Zealand they found an environment with plentiful food, few competitors and still fewer predators. In many parts of the country winters

are relatively benign, minimising mortality during hibernation, especially of the first-year young.14 In some parts of Europe, female hedgehogs produce two litters during a prolonged breeding season 56 and the same may be true in the warmer northern regions of New Zealand where winters are short. Reliable estimates of hedgehog densities in New Zealand are few, but their frequent appearance in predator trapping returns, and their widespread distribution, suggest that they have been very successful invaders. In the 1950s, the numbers of road-killed hedgehogs recorded in New Zealand (in places, 25–50/100 km or more) outnumbered those on British roads 30–40-fold, but since then, the numbers of kills counted on both UK and North I. roads have fallen dramatically, and are now similar (North I., 1.7/100 km in 2005; UK 1.5/100 km in 2004). The latest South I. count (12.5/100 km in 2007) was ~12 times higher than on any North I. road since 1990.18 These estimates might appear to infer real changes in hedgehog densities, but they do not take into account other influential factors such as variations in traffic density and habitats adjacent to the roads surveyed. A survey in the 1970s found that New Zealand ­hedgehog skulls averaged between 2 and 3% shorter than those of British animals, and bodyweights were also lighter. The mean weight of 277 New Zealand hedgehogs was 685 g, and the heaviest weighed 1300 g.14 The mean weight of British hedgehogs was 733 g,82 and weights of >1500 g were not uncommon.53,70 On the other hand, the milder parts of New Zealand are kind to hibernating hedgehogs, and they lose less bodyweight over winter than do hedgehogs in Europe. A heritable dental condition, present in ~16% of British hedgehogs but absent in continental Europe, was transmitted to New Zealand in the colonising stock. Of 90 hedgehogs, collected mainly in the Wairarapa in 1994, 63 (70%) had faulty lower teeth, with premolars missing in 41 (46%), incisors missing or rudimentary in 27 (30%), and molars missing in three (3%).27 A similar study in the southern North I. in the 1950s found dental abnormalities in 51% of hedgehogs (n = 77).13 New Zealand hedgehogs suffer more from the effects of mange mites than their European relatives. Mange caused by Caparinia tripilis kills hedgehogs much more often in New Zealand than in Europe.16 On the other hand, New Zealand hedgehogs carry few fleas. Nearly every European hedgehog carries very large numbers of the specific hedgehog flea, Archaeopsylla erinacei, but it has never been seen here.

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Table 3.3:  Parasites and diseases of hedgehogs in New Zealand. Name

Prevalence in New Zealand

Notes

Reference

Nosopsyllus fasciatus (rat flea)

3% of Wellington animals

Normal host is Rattus rattus.

11

Ctenocephalides felis (cat flea)

1% of Wellington animals

Normal host is the domestic cat.

11

Leptopsylla segnis (mouse flea)

Rare: one record, in Orongorongo Valley.

Normal host is Mus musculus.

40

Very common

Scabs may blind, disable, or kill many hedgehogs, particularly males. Spreads hedgehog ringworm.

Siphonaptera

Acarina Caparinia tripilis (hedgehog scab mite)

14, 111

Notoedres muris

Found on Auckland hedgehogs

Infected animals may lose their spines.

50

Hirstionyssus talpae

Isolated from hedgehog nest in Wellington

Blood sucking parasites.

117

Haemolaelaps megaventralis

“

“

“

Androlaelaps casalis casalis

“

“

“

Haemophysalis longicornis (cattle tick)

“

“

120

Sarcoptes scabiei (mange mite)

6 of 6 from urban sites, 0 of 14 from rural sites

Causes scabies in humans

Plagiorhynchus cylindraceus

8%: Auckland region 3.6% of 84 North I. 0% of 99 South I.

Intestinal parasite of passerine birds

107

Polymorphus spp.

Single specimen from Auckland region

Previously undescribed

108

Crenosoma striatum (tracheal worm)

13% of North I. hedgehogs

In trachea and bronchi. Contracted by eating slugs and snails.

11

Aonchotheca erinacis (stomach worm)

63% of Wellington animals

Found at Rotorua, Kaitaia, Palmerston North. May cause stomach lesions.

11, 76

Trichophyton mentagrophytes var. erinacei (hedgehog ringworm)

Very common, e.g. 47% of Dunedin animals

Produces dry scaly skin, occasional baldness in hedgehogs. Accounts for 360 species from >30 genera.88 Vespertilionid bats are among the most widely dispersed of mammals, found almost worldwide (except for the polar regions), including remote oceanic islands.

Genus CHALINOLOBUS Five of the seven species of Australasian wattled or lobelipped bats live in Australia (including Tasmania and Norfolk I.) and New Guinea; one in New Caledonia; and one, Chalinolobus tuberculatus, in New Zealand.88 They are small- to medium-sized bats which have a fleshy lobe on the lower ear margin, and often another at the corner of the mouth. The ears are short and broad, the tragus curves inwards, the forehead is high, and the muzzle has a glandular appearance.75

NEW ZEALAND LONG-TAILED BAT Chalinolobus tuberculatus (Forster, 1844) Synonyms Vespertilio tuberculatus Gray, 1843; Vespertilio tuberculatus Forster, 1844; Scotophilus tuberculatus Tomes, 1857; Chalinolobus tuberculatus Peters, 1866; Chalinolobus morio Thomas, 1889. Also called New Zealand short-eared bat or New ­Zealand wattled bat (English); pekapeka (Māori). The name Chalinolobus tuberculatus should be attributed to Forster (1844) rather than Gray (1843). Vespertilio (= Chalinolobus) tuberculatus was described by Forster in his journal, and illustrated by his son G. ­Forster, during Cook’s second voyage to New Zealand in 1773.90,182 There are significant differences among populations in size (Table 4.2) and calls.148,153 Earlier speculation that there were also significant differences in genetic diversity among populations proved unfounded, and the low levels of genetic differentiation do not warrant separation into subspecies.52,146

Description Distinguishing marks – see Table 4.1. A small, delicate bat, in contrast to the more robust Mystacina. The head is broad and forehead is high. The face is moderately hairy, with the nostrils set on prominences. The eyes are small with well-formed fleshy lids. The small ears and short tragus are rounded distally, and the outer margin of the ear continues along the face, beneath the eye, as an antitragus, which terminates just behind the lip-­ lobule. The more pronounced tragus extends from within the ear above the antitragus. It is narrow at the base but widens and is rounded distally (Plate 3). Pelage colour is variable in living wild bats, and changes with age. Adult females usually have rich chestnut upperparts, sometimes with white tips to the fur. Males, and 1–3 year olds of both sexes, are darker, with dark brown upperparts and blackish fur around the head. Underparts are pale brown in both sexes, paler about the pubic region. The fine, soft dorsal fur is up to 7 mm long, with no differentiation into overhair and underhair. The fur of preserved museum specimens is often bleached to a light reddish-brown. The limbs, wing, and tail membranes are almost naked and blackish-brown in colour. The bones of the leg and forelimbs (except the thumb) are long and slender. The small thumb projects free from the wrist and carries a long-curved claw. The small hind foot is turned outwards. The calcar extends from the heel as a strong process and supports almost half of the posterior border of the large interfemoral membrane. A small, rounded post-calcareal lobe is present near the base of the foot. The relatively long, pendant penis of the male makes for easy distinction of the sexes. Females without visible nipples, or with nipples covered in fur, are non-­ reproductive.140 Nipples remain conspicuous after females have given birth once. Non-volant young are recognisable by their small size, patches of bare skin, and short, greyblack fur. Young-of-the-year are recognisable until phalangeal epiphyses are fully fused at ~3 months old. Search phase echolocation calls of long-tailed bats (Fig. 4.1) begin with a steep, downward frequency-­ modulated sweep, followed by a short, less modulated component at lower frequencies. Up to three harmonics are usually present, although some calls have none. Peak amplitude is in the shallow tail of the fundamental call at ~36–40 kHz, depending on population. Search phase calls averaging 6.3 ms long sweep through ~30 kHz from 65–34 kHz.148,153

4 – Families Vespertilionidae and Mystacinidae

Table 4.1:  Distinguishing marks of New Zealand bats. For echolocation calls, see Fig. 4.1.

Long-tailed bat Chalinolobus tuberculatus

Lesser short-tailed bat Mystacina tuberculata

Greater short-tailed bat Mystacina robusta

Flying activity starts

Before or just after sunset

After dark

After dark

Roosts

Native and exotic trees, caves

Native trees and caves

Native trees, caves, and seabird burrows

Tail length and position

Almost as long as head and body, embedded within large ‘V’-shaped interfemoral membrane

Very short, partly free of interfemoral membrane, projecting ~7 mm on dorsal surface

Fur

Variable colour, fine and soft. Adult females usually rich chestnut brown upper parts. Males and non-breeders dark brown with blackish heads. Underparts pale brown

Short and velvety, grey-brown, guard hairs over underfur

Jaws

Fleshy lip-lobule at corner of mouth.

No lip-lobule

Hind legs

Small, delicate feet. Legs enclosed within interfemoral membrane

Large, robust legs, not fully enclosed by interfemoral membrane

Claws

Without spurs on toes and thumbs

With spurs

Ears

Small, broad, rounded

Large, pointed, extend to or beyond muzzle when laid forward

Large, pointed, do not reach muzzle when laid forward

Nostrils

Small

Prominent and narrow

Short and broad

Forearm length Bodyweight

37–46 mm 7.1–12.5 g

39–46 mm 10–22 g

45–48 mm ?–24 g

Figure 4.1:  Echolocation call structures for New Zealand bats: plots of audio frequency against time.107 Amplitude is represented by the intensity of shading. Left: Twenty-five millisecond sequence, showing individual pulses. Right: half-second sequences showing pulse trains.

Chromosome number 2n = 36. Dental formula I 2⁄3 C 1⁄1 Pm 2⁄2 M 3⁄3 = 34. The complete mitochondrial genome of the long-tailed bat has been mapped (GenBank accession number AF321051).104

Field sign Long-tailed bats leave little sign of their presence because they are nocturnal and rare. They are visible flying in twilight for ~45 min after sunset, when it becomes too dark for people to see them. Most roosting cavities are

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124 53.5 ± 0.1

90% of females are pregnant from August to ­February. The season starts 1–2 weeks earlier in mild than in cold winters, and young females breeding for the first time start 3 weeks later than adults. Mating is promiscuous, and the female accepts any dominant male. Ovulation is induced but, because sperm may remain viable for as long as the 42-day gestation period, the paternity of subsequent litters is uncertain.134 Superfoetation (overlapping pregnancies) is common in captivity, where the mean interval between births was 38 days,133 but only three of 24 females with full-term embryos showed superfoetation in the wild.56 The oestrous cycle is 7 days in non-pregnant females, every 13–14 days if pseudo-pregnant, up to 10  days before the end of pregnancy for pre-partum ­oestrous, or immediately post-partum.27 In lowland New Zealand, up to 70% of young female hares >2.7 kg (~5 months old) bred in the same season in which they were born. Only in April were no males fecund, and only in May were no pregnancies recorded. Embryos tended to occupy alternate uterine horns in successive pregnancies. The mean number of corpora lutea per litter in adult females (2.8) rose from 1.0 in June to 3.8 in November before declining slightly. The average litter size (measured at ~32 days of gestation when embryos weighed >30 g) was 2.14, and the average number of successful litters per year 4.59, giving an annual production of 9.8 young per female, allowing for pre-and post-implantation loss. Young females had small litters (1.4) and contributed little to the population in their year of birth.56 Among 2208 hares from subalpine Canterbury, adult females were pregnant from July to mid-March, and most (64–72%) had implanted embryos from August to ­January, but no juvenile females were breeding during the season of their birth.184 The testis weight of adult males was highest between July and January. The annual cycle of fat deposition and use, controlled by an endogenous mechanism, increases the energy reserves of females from autumn and throughout pregnancy, and releases energy in winter, especially in lactating females.57,184

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Mean litter size of L. europaeus is inversely correlated with average annual temperature, ranging from 2.8 at 7°C (in Sweden) to 2.2 at 12°C (in the North I.).20 The North and South islands’ hares collected below 300 m fit this trend roughly, although in Canterbury a large sample of hares from high altitude (>700 m) did not have larger litters than those from 100 ha, and even then they partition strongly by habitat.76,256,551 Norway rats in New Zealand forests, as on most forested oceanic islands, can be out-competed and displaced by ship rats when access to arboreal resources is an advantage.331 However, Norway rats can sometimes maintain an incumbent advantage as the resident rat species when

Predators, parasites and diseases The main predators of Norway rats in New Zealand are cats, stoats, ferrets and swamp harriers (Circus approximans). Adult rats may be able to defend themselves against the smallest of these predators, but juveniles would be vulnerable to them all. Observations of individual rats being killed do not necessarily equate to the rat population being regulated by predation.547

rats. The only certain signs are internal, i.e. the presence of corpora lutea or uterine scars in females, and mature sperm in males. Age of rats from 1–22 months old can be estimated from the dry tissue weight of eye lens pairs.319 Body mass and total adult skull length of Norway rats are predictably correlated: on average, each 1 mm increase in skull length is accompanied by an increase in body mass of 25.88 g.713 Rats trapped in Pureora FP grew continually to age class 6 as defined by Karnoukhova318 (Fig. 6.3); older rats declined in weight, but not in linear measurements, suggesting a drop in condition.304

6 – Family Muridae

Ectoparasites reported from Norway rats in New Zealand include seven mites (Androlaelaps casalis, Haemaphysalis longicornis, Hirstionyssus latiscutatus, Hypoaspis nidicorva, Notoedres muris, Ornithonyssis bacoti and Radfordia ensifera); two lice (Polyplax spinulosa and Hoplopleura pacifica); and seven fleas (Leptopsylla segnis, Nosopsyllus fasciatus, Pulex irritans, Pygiopsylla hoplia, P. phiola, Xenopsylla cheopis and X. vexabilis).625 Endoparasites include the nematodes Mastophorus muris, Nippostrongylus brasiliensis and spiruroid species; the tapeworms Cysticercus fasciolaris and Hymenolepis diminuta; and the trypanosome Trypanosoma lewisi.114,428 In many countries, Norway rats transmit serious human diseases.43,271 In New Zealand they have been recorded as reservoirs for leptospirosis, salmonellosis, trichinosis, toxoplasmosis, murine typhus and rat-bite fever, and are likely hosts for other diseases; they are a particularly important reservoir for Leptospira interrogans serovars ballum and copenhageni,232 with infection rates of 20–43% in rural areas of the North I.114 Although these have not been the most common serovars infecting humans in the past,7 infections by serovar ballum are on the rise,370 and its prevalence has previously been correlated with the density of Norway rat populations.267 Adaptation to New Zealand conditions The decline of the abundant Norway rats in nearly all forests on the North and South islands of New Zealand in the 19th century is now attributed to the spread of ship rats,563 which, in the absence of other arboreal rodents such as squirrels, can out-compete Norway rats in foraging above the ground, whereas the converse is observed in the UK.331 By contrast, Norway rats are superior to ship rats in dispersal over water, so until the era of numerous island eradications (Table 6.2) Norway rats were more commonly found on offshore islands, the result of a competitiondispersal trade-off with ship rats.551 Differences in diet between Norway rats in New Zealand and elsewhere reflect the particular foods available rather than intrinsic changes in feeding habits. Other potential differences in morphology, breeding, behaviour and ecology have not been studied in detail. Significance to the New Zealand environment Damage. Initially the Māori prized the large Norway rats as food, but eventually came to reject them because of their unclean habits.54 Within a few years of their arrival,

certainly by 1832, Norway rats were seriously damaging food stores in Māori settlements in the Bay of Islands.682 Norway rats are still important commensal pests, because they chew plastic fittings and spoil stored food, especially in warehouses, and they continue to damage agriculture. Along with the other rat species in New Zealand, Norway rats are a serious public health hazard. The terrestrial habits of Norway rats make native animals that live, roost or nest on or near the ground particularly vulnerable, especially frogs, reptiles, wetland birds and seabirds.314,469,637 At the beginning of European settlement there were still many species that had survived kiore depredation during the Polynesian period, but which were devastated by the newly invading Norway rats, e.g. southern New Zealand dotterel Charadrius o. obscurus.182 The rats take eggs and nestlings, and are also large enough to kill adults, not often but more frequently than do ship rats or kiore. The effects of this predation depend on the behaviour and ecology of both the birds and the rats,430 and range from negligible225 to complete failure of nesting,287 or even local extinction. This topdown moderated impact of Norway rats on seabirds has flow-on indirect effects to the entire trophic architecture and ecosystems of islands.221,438,642 In general the presence of Norway rats on New Zealand offshore islands is negatively correlated with seabird species richness;551 but seabird populations usually recover after Norway rat eradication.104 On Campbell I., the locally endemic snipe Coenocorypha aucklandica perseverance, pipit Anthus novaezeelandiae and flightless teal Anas nesiotis, plus all the small petrels, had disappeared from the main island and were restricted to rat-free offshore islets by the time the rats were eradicated in 2001, but are now returning or being reintroduced.417,474 On Kapiti I. before the eradication, half of all kākā (Nestor meridionalis septentrionalis) nests within 1 m of the ground were destroyed, mostly by Norway rats,425 and North Island saddlebacks (Philesturnus carunculatus rufusater) could not fledge sufficient young to maintain the translocated population.360 More saddleback pairs were observed in 1998, the first breeding season since the eradication, than previously.197 On the other hand, the numbers of sooty shearwaters (Puffinus griseus) and flesh-footed shearwaters (P. carneipes) breeding on Titi I. (Cook Strait) did not increase after Norway rats were eradicated in the 1970s, perhaps because the island was always on the margin of these species’ ranges.225

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On Whale I., Norway rats ate unattended eggs and young or weak chicks of grey-faced petrels (Pterodroma gouldi). Petrel breeding success was reduced by 10–35% until rabbits (introduced ~1968) became very abundant by early 1973, after which the rat population increased. Production of fledged petrel young declined to near zero during 1972–77, but recovered after 1987 when both Norway rats and rabbits were eradicated.286 Single Norway rat incursions eliminated most of the Mana and Waikawa/Portland islands populations of reintroduced New Zealand plover (Thinornis novaeseelandiae).74,183 The patchy distribution of Norway rats on the main islands of New Zealand means that they are a less widespread threat than are ship rats, but they are locally important. Norway rats were probably responsible for the removal of over two-thirds of chicks and some eggs and juveniles from colonies of endangered black-fronted terns (Sterna albostriata) breeding on the ground in South I. braided riverbeds,320,602 and they accounted for nine (25%) of mammal predation events at nests of northern New Zealand dotterels Charadrius obscurus aquilonius on Matakana I., Tauranga.182 The larger ground-dwelling invertebrates have suffered wherever Norway rats arrived. Norway rat predation decimated beetles, wētā and harvestmen on Breaksea I.,80 but after rats were eradicated in July 1986,620 the numbers of invertebrates, and of seedlings of 19 of 24 species of trees and shrubs, increased substantially.6 Fiordland skinks Oligosoma acrinasum recolonised the island from adjacent rock stacks, and endangered native weevils (Hadramphus stilbocarpi and Anagotus fairburni) and South Island saddlebacks (Philesturnus carunculatus carunculatus) were successfully reintroduced.620 A 100-year recruitment lapse in populations of the dominant beech trees on the island suggested that rat predation had been an important constraint on the regeneration of these tree species since the mid- to late 19th century.6 Rat eradication tends to promote a more natural state of ecosystems.243,244,480,656,657 However, ecosystem restoration does not guarantee any particular species recoveries. No recovery of invertebrates was observed after the eradication of Norway rats and kiore on Kapiti I. in 1996, perhaps because there was a concomitant increase  in native avian predators,585 and the expected increases in woody plant regeneration were masked by natural variation.109 Similarly, after Norway rat eradication from Ulva I. in 1996 there was no significant

increase in woody seedlings or saplings, although the benefits of rat removal could not be clearly distinguished from those of the deer eradication 20 years earlier.131 Control. Norway rats were once common on offshore islands of New Zealand, but have now been eradicated from most of them.134 Eradication of rats from islands started with ground-based methods,284 and the steady development and refinement of this technique has allowed an escalating scale of eradications,627 beginning with two small (150 m between captures. On an irrigated cereal farm in Australia, mice had exclusive territories one year but group territories the next.508 The group territory was associated with higher fertility rates and a more stable population. Although dominance hierarchies and group territories can restrict gene flow,355,588 population turnover in the wild is so high that this effect is unimportant, and genetic diversity is maintained.52,586 Reproduction and development As a laboratory animal, the house mouse has become a model for many reproductive studies; hence, there is a very large literature on reproduction of caged and commensal mice, but less concerning wild mice.589 Maturity. Age at sexual maturity is a critical variable determining population growth rate. Wild mice cannot be aged precisely,589 because the existing age categories based on toothwear are broad.354,500 Head–body length and bodyweight may be used as proxy variables,171,460,543 although both are affected by diet and season.332,441 Commensal mice of both sexes living in grain stores and suburban and pastoral areas near Christchurch became

6 – Family Muridae

sexually mature at ~8 weeks old and 10.6–12.5 g bodyweight.231 The same was true of wild mice in summer, except that those born at the end of summer did not reach sexual maturity until the following spring.29,441,491 Mice living on the mainland in the Marlborough Sounds became sexually mature at an earlier age than mice living on a nearby island, and male mice at an earlier age than females.441 Breeding rate and season. Breeding normally ceases in winter,29,205,332,411,414,441,491 except in commensal mice231 and in beech forest and alpine habitat after moderate to heavy mast seeding.205,325,441,536,695 Juveniles usually enter the trappable population in summer and autumn, sometimes in large numbers. Pregnant and lactating females, and recently independent juveniles, have been caught in other months, indicating continued but less frequent breeding over winter.411,414 As some adult males remain fertile throughout the year,29,441,491 the breeding season is determined primarily by factors acting on the females, especially food supply589 and the energetic cost of thermoregulation in different weather conditions.390 A sudden mouse irruption in a young pine plantation at Pureora Forest in autumn (May 1984) was due to improved recruitment rather than to an extended breeding season.332 Supplementary food (wheat) was added to island and mainland habitats in the Marlborough Sounds to test whether food quantity is critical.441 The mainland population remained so low that no change could be detected, and on the island, although a few adult females did breed during the winter, sexual maturation of young females was still delayed. Further experiments are needed to test whether reproduction in winter is also limited by low quality food.69,441,681 In beech forests, breeding rate is highest in years of heavy seedfall, in older females, and early in the breeding season.209,325,326 Continued population growth, leading to very high density indices in spring, is usually associated with extended breeding through the winter.325,443,536 For example, no young mice (1–2 months old) were caught in the winter preceding a heavy seedfall in the Marlborough Sounds, but they made up 42% of the winter population following the seedfall.443 By contrast, the opposite effect was observed in the Orongorongo Valley (a beech–podocarp forest), where 72% of females were pregnant in summer during beech flower fall, but pregnancy rate was low for the following 18 months (‘the post-mast’ year), including the post-seedfall winter.209

Data collected on subantarctic Marion I. over three decades revealed a shift to an earlier breeding season, related to the number of precipitation-free days during the winter. This change was sufficient to explain an increase of 430% in peak annual density over the duration of the study.390 After winter breeding, pregnancy rates in the following spring and summer may443 or may not205 be depressed, depending on whether other foods are available after the spring germination of seed.535 For example, in the Eglinton/Hollyford Valleys after winter breeding in 1976, 34% of 32 females were pregnant in summer 1977 at a density of 24.7 C/100TN;325 by contrast, in the Grebe and Borland valleys in winter 1979, 50% of 12 females were pregnant at a density of 15.8 C/100TN, but 3 months later the spring density had reached 73 C/100TN and pregnancy rate was down to 7%.325,326 Fertility. In female mice the oestrus cycle lasts 4–6 days, and pregnancy 19–21 days. Ovulation is spontaneous, and copulation leaves a vaginal plug that lasts for 18–24 h. The oestrus cycle stops during lactation, except for one oestrus 20 h post-partum.595 At Woodhill, 45% of mice pregnant in the August 1976 to April 1977 season were lactating, indicating post-partum fertilisation.29 In the Orongorongo Valley, only 11% (n = 75) of pregnancies observed between 1971–94 were post partum.209 When this happens, a brief period of delayed implantation extends the pregnancy by several days,595 so the interval between litters varies from 20 to 30 days. Average litter size in New Zealand is 6, varying locally from 5.0 to 6.9 (range 2–9).29,325,332,411,414,441,491 There is no clear relationship between female age and litter size.29,231,325,441 Resorption of embryos is frequent (e.g. on Mana I., at least one in 18% of litters, total 6% of all embryos192). Newborn mice weigh ~1 g, are naked except for short vibrissae, and their eyes and ears are closed. By 14 days they are fully furred, with their eyes and ears open and incisor teeth erupted. The young start to leave the nest after weaning at 20–23 days old, weighing ~6 g.482,595 On Allports I., Queen Charlotte Sound, in 1987, the breeding rate of mice severely infected with the bile duct tapeworm Vampirolepis straminea was depressed,442 perhaps because it exacerbated environmental stress (e.g. bad weather, food shortage). In laboratory conditions, infection with this tapeworm significantly increased the delay between first and second litters, but did not decrease number of litters or total number of offspring produced per female.

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Population dynamics Density. Trapping-derived indices of mouse abundance demonstrate large seasonal and annual variations, both within and between different habitat types (Table 6.9), which are still obvious even though the indices listed are

not all entirely comparable. In beech forests, capture rate indices, C/100TN, can increase dramatically, from near zero to very high densities in a few months. They may reflect changes both in numbers and in trappability, in unknown and variable proportions.82,209 Increasingly,

Table 6.9:  Indices of abundance (captures per 100 trap-nights) and density estimates (individuals per hectare) for mice in New Zealand. Habitat type

C/100TN

Density/ha

Months

Borland Valley

-

0.02–1.8

Craigieburn FP

0–23.4

-

Feb, May, Aug, Nov

Years

Reference

2003–2004

695

1974–77

326

Beech forest

Grebe and Borland valleys

Feb, May, Nov

15.8–73.3

-

Aug, Nov

1979

326

Monowai-Grebe Valley

1.5

-

May

1967

121

Caswell and George sounds

0.3

-

Mar

1949

703

Lake Monk

0.4

-

Mar, Apr

1957

515

0–24

-

Feb, May, Aug, Nov

1973–80

326

-

68% of dives exceed their aerobic dive limit,83 suggesting that New Zealand sea lions may be operating near their physiological maximum.89 There is limited information on the foraging behaviour of adult male New Zealand sea lions.123 A satellite tracking study from Enderby I. showed one adult male transiting between the Auckland and Campbell islands and then foraging over the continental shelf around Campbell I., while the other foraged over the continental shelf off the Auckland Is further out than adult females.83,123 At the Auckland Is, juvenile females (1–3 years) foraged closer to shore and had shallower dives than either adult females or juvenile males.199–203 Juvenile males (2–5  years) foraged in a similar range and with similar dive depths to adult females.199,202,203 At Otago, only juvenile females (2–3 years) showed similar foraging ranges to the adult females in the area.7,10 Food The diet of New Zealand sea lions has been comprehensively studied using four methods: (1) faeces and regurgitated hard part analysis;12,63,239 (2) stomach analysis of bycaught animals;239 (3) fatty acid analysis of blubber;240–243 and (4) stable isotope analysis of blood and whiskers.71 The dietary time frame represented by these four methods varies from several days (e.g. hard part analysis) to the whole life of the animal (e.g. stable isotopes from whiskers or teeth). New Zealand sea lions are considered generalist opportunistic feeders, targeting varied prey species based on what is available in their

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Raoul Island

Chatham Islands

5 km

50 km

Antipodes Islands

Auckland Islands

5 km

25 km

Campbell Island

15 km

Mainland distribution Mainland breeding areas Rookeries and hauling grounds

Otago Peninsula Catlins

0

250

KILOMETRES Port Pegasus / Pikihatiti

Figure 7.2:  Distribution of New Zealand sea lions in the New Zealand region. There are rookeries on Auckland, Dundas, Enderby, Figure of Eight and Campbell islands. New Zealand sea lions also breed on the South I. and Stewart I./Rakiura.

7 – Families Otariidae and Phocidae

foraging environment, introducing variation into their diet through time following changes in prey availability.240 Hoki (Macruronus novaezelandiae), rattails (Macrouridae spp.), opalfish (Hemerocoetes spp.), red cod (Pseudophycis bachus), arrow squid (Nototodarus sloanii), octopus (Enteroctopus zelandicus) and various benthic crustaceans, including scampi (Metanephrops challenger), dominate the diet of sea lions in the subantarctic.239,240,242 The Otago population also feeds on seasonal prey not found in the colder areas of the Auckland Is, such as barracouta (Thyrsites atun), Jack mackerel (Trachurus sp.) and coastal Octopus (Maorum spp.).12 Social organisation and behaviour The polygynous behaviour of the New Zealand sea lion on Enderby I. has been well described.79,216,271 Territories. Adult males establish territories on the breeding beaches, each covering ~5 m diameter of personal space, and defend them vigorously. Challenges from peripheral males are frequent and can lead to fierce fights.216 Male sea lions use ritualised posturing, bluff charges and oblique stares when faced with challengers.271 Peripheral males attempt to secure females physically, but territorial males rarely attempt to restrain female movements.79 Adult females aggregate in groups on the beach away from the surf line.9 They have no discernible social hierarchy and prefer to lie in contact with one another. Within harems, females are tolerant of young pups but less tolerant of neighbouring females shortly after giving birth. Post-partum aggression is relaxed 2–3 days after birth. Reproductive behaviour. Adult males haul out between October and early November,14,271 and the pregnant females arrive in early December.9,78 Pregnant females come ashore 2 days before giving birth. After parturition, mothers suckle their pups for 8−9 days before leaving on their first foraging trip, and during that time come into oestrus and mate.78 Pups are born on the beach. Females about to give birth separate themselves from others, become agitated, and flip sand over themselves to keep cool. Females and pups identify one another by smell and by sound (each makes a distinctive call quickly learned by the other). From the time of their mother’s first foraging trip, pups congregate into pods near the shoreside boundaries of the harem and will move about independently of their mothers at 1 km, and dives as deep as 2389 m are known (Table 7.2).164 In males, the skull grows continuously in length, width and height up to 11 years of age, especially in the snout and facial region, where extra strength is needed to support the proboscis. In females, growth in facial height and width ceases after 30–40 months of age, but continues in cranium and facial length very slowly throughout life. The incisors and post-canine teeth are much reduced, but the canines are well developed, particularly in males. Chromosome number 2n = 34. Dental formula I 2⁄1 C l ⁄1 Pm 4⁄4 M 1⁄1 = 30. Field signs Moulting elephant seals leave strips of epidermis and hairs in tussocks adjacent to sandy beaches or in deep, muddy wallows. On beaches, trails are formed in the sand as the cumbersome seals haul themselves along.

Measurements Elephant seals show extreme sexual dimorphism. On ­Macquarie I., adult males reach up to 5.36 m standard length and 3700 kg.208 Females average 2.64 m standard length and 506 ± 111 kg (range 346–803 kg).115,223 Breeding males are therefore up to 10 times the weight of breeding females, but females vary in size threefold. Newborn pups at Macquarie I. weigh 41.8 ± 6.9 kg, and can nearly triple their mass by weaning, 18–22 days later (mean 113 ± 16.6 kg).165 Weaning weight, however, varies annually according to prevailing environmental conditions, particularly for males.232 Distribution World. The southern elephant seal has a circumpolar distribution, mainly in subantarctic waters, ranging from 16°S at St Helena to the southern limit of open water at around 78°S.167 Most breeding colonies and hauling-out places are on subantarctic islands between 40° and 62°S in the South Indian and South Atlantic oceans, although there is a significant and growing population at Peninsula Valdes (42°S) on mainland Argentina.54 There are four main breeding stocks: (1) in the South Atlantic Ocean, breeding on the Falkland Is, South ­Georgia I., Signy I., the South Shetland Is, the South ­Orkney Is, Gough I. and Bouvet I.; (2) a genetically distinct population at Peninsula Valdes; (3) in the South Indian Ocean, on Marion I., the Crozet Is, Kerguelen Is and Heard I.; and (4) in the South Pacific Ocean, breeding on Macquarie I., Campbell I. and the Antipodes Is.168,209,294 There is little genetic interchange between the four breeding populations,294 but during their long forays at sea the populations could occasionally overlap at foraging grounds. Elephant seals have been reported many thousands of kilometres from their natal sites; e.g. one young female hauled out to moult 5200 km from her birth site, Macquarie I., and was seen later to have returned there.163 Long-range paternal gene flow between distant populations has been recorded;112 however, the populations as a whole remain quite distinct.88 New Zealand (Fig. 7.3). The New Zealand population is concentrated on the Antipodes Is and Campbell I. During the breeding season, some adult females move from ­Macquarie I. to Campbell I.;329 in winter, elephant seals frequently visit the Auckland, Antipodes and Snares islands, less often the Chatham Is, and occasionally mainland New Zealand, from Stewart I./Rakiura to the Bay of Islands. Pups have been born along the east coast

7 – Families Otariidae and Phocidae

0º

South Atlantic Ocean

A n t arc t i c

Con v

erg

e

n

ce

Indian Ocean

Southern Ocean

90ºW Southern Ocean South Pacific Ocean

90ºE

75

ºS

60

ºS

45

ºS

30

ºS Tasman Sea 180º

Rookeries Non-breeders and visitors

Figure 7.3:  Circumpolar distribution of southern elephant seals. The dashed line shows the approximate location of the Antarctic Convergence.

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of the South I. at Kaikōura;37,247 between 1965 and the early 1990s, pups were recorded frequently between Oamaru and Nugget Point.184 The current status of the southern elephant seal in New Zealand is unresolved,164 but new approaches using satellite telemetry might help resolve the issue of monitoring remote sites.233 Habitat Elephant seals have limited mobility on land, so they tend to haul out on easily accessible sand or gravel beaches. On subantarctic islands they lie on sand, in mud wallows or among the tussock grasses (Poa spp.) adjacent to beaches. Food The diet of elephant seals at sea is poorly known because they spend considerable periods (months) diving hundreds of kilometres from their main haulouts.166,225 Reconstruction of the diet from samples retrieved at haulouts are biased towards recent meals and may not represent their diet as a whole. Stomach samples examined from the Falkland Is contained cephalopod and fish remains;190 at South Georgia, samples contained 14 species of squid from 11 families, and two species of octopod from one family, but no fish;273 at Heard I., five species of squid predominated, especially two species of Moroteuthis, plus fish (in 77.3% of stomachs); and at Macquarie I., samples contained mostly Histioteuthis eltaninae and fewer fish (33.8%).132 Seals using shelf and pelagic habitats had diets high in fish content, whereas seals exploiting habitats in the pack ice had a more mixed diet of fish and squid.17 Social organisation and behaviour Elephant seals are gregarious and have well-defined seasonal cycles and a wide range of behaviours appropriate to each age, sex and season. Reproductive behaviour. At the beginning of the breeding season, in early August, sexually and socially mature males haul out on the beaches. Prolonged and frequent agonistic behaviour, involving vocal exchanges, posturing and fierce combat, resolves into a dominance hierarchy.221 Physical fights are spectacular, but rare: only 4% of interactions involve physical contact and 12 years). They dominate all males associated with a particular harem, and attempt to deny competitors access to females. However, dominance hierarchies are dynamic, and the α position can change during the course of a breeding season. Lower-ranking males (challengers) are present in the largest harems, and the lowest-ranked of all, peripheral males, pursue females when they leave the harem and enter the water at the end of the breeding season.120 Genetic analyses of paternity have demonstrated that although α males achieve the highest reproductive success, they do not always successfully exclude other males. At Peninsula Valdes, 21 of 50  pups sampled were sired by a male other than the α male,169 including three by previous α males, one by an α at another harem, one that had been an α at another harem previously, six by non-α males, and 10 not matched to any males sampled at the beach. Observed copulations were no indicator of reproductive success, with only 30% resulting in paternity.169 More than half the females observed at Peninsula Valdes copulated with more than one male.54 Reproduction and development The reproductive season is a fixed 3-month period, varying in exact timing with latitude. The day on which the maximum number of females is hauled out varies from 2  October at Peninsula Valdes (42°S) through to 15 ­October at Macquarie I., 18 October at Heard I. (53°S) to 25 October at South Georgia I. (54°S) and King George I. (62°S).54,119,230 Adult males occupy the breeding beaches between September and December, and some may stay ashore, fasting, for up to 3 months. Females begin to haul out a few days before parturition in early to mid-September, give birth ~5 days later, suckle their pup (twins are very rare) for ~3 weeks, mate once or more over a 2-day period in November, and then return to the sea. Small and young females tend to arrive earlier than large females, and departures are less synchronised than arrivals.230 The cost of reproduction is high,101 and females may skip years.100 Total time ashore for individual females is up to ~28 days, spread over ~60 days.119,158,230 Lactation lasts for an average of 23 days, but larger females may suckle their pups for longer, presumably because they have larger fat reserves.53,232 Females usually suckle only their own pups. Oestrus is 18 to 20 days post-partum and strongly synchronised, but the implantation of the blastocyst is delayed until late February or early March.208

7 – Families Otariidae and Phocidae

Weaned pups stay ashore for 40–50 days, living on stored blubber reserves and learning to swim. They lose ~30% of their mass during this post-weaning fast.5 By the end of December, all weaners have left the beaches, and will disperse considerable distances (up to 10 km) from the natal site.113 They do not reappear until May–midJuly (mean trip duration 182 ± 51 days).295 Their body mass increases by ~75% during this first foraging trip, at a rate of 0.34 ± 0.12 kg per day.20 The mean standard length of Macquarie I. elephant seal pups at weaning has decreased by 3 cm between the 1950s and 1990s, concurrent with an overall population decline, suggesting a decline in available food supplies for mothers.86 Population dynamics Numbers. At the Antipodes Is, probably the main New Zealand breeding area, 113 pups were born in 1978.310 At Campbell I., production of pups declined by 97%, from 191 in 1947 to 5 in 1986.310 The Macquarie I. population, estimated to be ~156 000 in 1959, is now down to around 90 000, and is continuing to decline at ~1.2% per year.157,167 Other elephant seal populations in the Indian and Pacific oceans have also been declining, although the losses appear to have halted in some areas. At Iles ­Kerguelen, the population declined from ~70 000 in the 1950s to 35 000 in the mid-1980s, was stable for a period, and is now around 40 000 and rising at ~1% a year.133 Pup production on Heard I. has declined from >32 000 in 1946 to just over 13 000 in 1985,52 probably also due to changes in food availability.234 By contrast, populations in the Atlantic are stable or growing. South Georgia supports more than half the world’s elephant seals (the annual estimate of >460  000 has not changed for at least 45 years), and annual pup production is around 100 000.40,193 At Peninsula Valdes, the latest population estimate is 45 800 adults, pup production is >9000 a year, and the total population is growing at ~2.8% a year.53,204 Age and mortality. Males can live to 23 years, but have significantly lower age-specific survival than females, and 97.4% have died by the age of 10.157 At Marion I., males do not generally live beyond 13 years, and 93% of females do not reach 14 years.261 However, females branded as pups on Macquarie I. have been seen alive and successfully breeding at 23 years of age.162 Females first breed at between 4 and 7 years of age (mean at Macquarie I., 5.2 ± 1.8 years), although there is a

significant cost to first reproduction,101 and the estimated annual fecundity rate at South Georgia is 0.391.157,222 At Peninsula Valdes, 96% of females that come ashore give birth, and in the Falkland Is, 100%.54,119 The sex ratio is usually unbiased, and pre-weaning mortality is ~5%.158,230,231 Although sexually mature from ~5 years of age, males avoid the conflict in the breeding areas until they reach social maturity. They start attending breeding harems at the age of 10 years; some males (16%) do manage to breed as peripherals or challengers at that age, but few males under 12 years can successfully dominate in harems.174 In the population at Macquarie I., currently declining at 1% a year, survival to weaning from 1–3 years of age is 78% and from 4 years on is 85%.231 Predators, parasites and disease Killer whales regularly attack young elephant seals at Macquarie I., Crozet I., Marion I. and off Argentina.266 Sleeper shark (Somniosus antarcticus) bites are seen on elephant seals at ­Macquarie I.330 Wounds caused by sharks, leopard seals and killer whales, and by New Zealand sea lions killing and eating yearling elephant seals, have also been observed at Campbell and Auckland islands. The tapeworm Baylisiella tecta is specific to the southern elephant seal. The louse Lepidophthirius macrorhini makes burrows in the skin of the hind-flippers.250 There is no evidence of widespread disease in southern elephant seals.229 Significance to the New Zealand environment Intensive harvesting of southern elephant seals from Campbell I. and elsewhere, primarily for blubber oil, finished (except at South Georgia) in 1830. Elephant seals generally live in remote areas so have little potential as a recreational resource, although there is always keen local interest whenever they come ashore near populated areas. One old male, ‘Humphrey’, ­frequented the Coromandel Peninsula and the Bay of Plenty each summer for the 5 years to 1989–90,92 and more recently ‘Homer’ hauled out for several years at Christchurch, and then shifted to Gisborne in 2000.99 Although popular with locals and visitors, the impact of an amorous but short-sighted 2-tonne male elephant seal on cars and other structures is significant. Visits by tour ships to populations at Macquarie I. and South Georgia I. are strictly controlled under the ­Antarctic Treaty. The effects of research and other forms of human disturbance on female elephant seals and their

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pups has been measured.107–109 Females in areas often visited by people do appear disturbed, as they move about the beach more frequently, but handling for research causes no biochemical changes or differences in weaned pup mass. Elephant seals are fully protected, both in New Zealand waters under the Marine Mammals Protection Act 1978 (New Zealand), and south of 60°S under the Antarctica (Environmental Protection) Act 1994 (New Zealand), which implements the Convention for the Conservation of Antarctic Seals 1972. They are assessed as ‘Least Concern’ on the IUCN Red List.170a Acknowledgements The pinniped chapter in the first edition was written by M.C. Crawley, and in the second edition by R.G. Harcourt. This edition was updated by R.G. Harcourt and B.L. ­Chilvers, and refereed by R.H. Taylor and C.R. McMahon. Citation format for this species Harcourt RG, Chilvers BL (2021) Mirounga leonina. In The Handbook of New Zealand Mammals. 3rd edn. (Eds CM King and DM ­ Forsyth) Families Otariidae and Phocidae, pp. 241–277. CSIRO Publishing, Melbourne.

Genus LEPTONYCHOTES The only species in this genus, L. weddellii, is one of the most fully aquatic seals, well adapted to life in the cold Antarctic seas. It inhabits the inshore waters of the ­Antarctic continent and hauls out on beaches or fast ice.

WEDDELL SEAL Leptonychotes weddellii (Lesson, 1826) Synonym Otaria weddellii Lesson, 1826. Description The distinguishing features of the Weddell seal are shown in Plate 6 and Table 7.1. The Weddell seal is one of the largest of all seals, but the head is exceptionally small relative to the size of the body. It has a short muzzle and short vibrissae, and large, deep-brown eyes. The entire body is covered with thick fur, except for small portions of the underside of the flippers. After moulting, the back is blue-black, grading to a silver-white spotting on the belly, and fading with age to a rust-brown on the back just before the next moult. The pups’ natal grey-brown coat, much longer than the fur of the adult, is shed 9–21 days after birth.339

Weddell seals are the most vocal of all seals. There is significant seasonal and geographical variation in their 21 to 44 recognisably different calls and songs.258,259,312,313,321,323 Males call almost continuously during the breeding season, including the male-only trills (in McMurdo Sound) or songs (Vestfold Hills Fjords) probably used to attract females or for territorial defence.248,322 The distinctive skull has exceptionally thin, light bones for such a large mammal. The canines are robust and project forward, as do the incisors, forming an effective ice reamer with which the seals (both sexes) maintain breathing holes in the sea-ice throughout winter. The canines can wear through to the pulp cavity, sometimes leading to infection and ultimately death.302 In contrast to those of the elephant seal, the post-canines are strong. Chromosome number 2n = 34. Dental formula I 2⁄2 C l ⁄1 Pm 4⁄4 M 1⁄1 = 32. Measurements Female Weddell seals in McMurdo Sound ranged from 187 to 265 cm in nose-to-tail length153 and averaged 447 ± 52 kg, range 342–524 kg (n  =  14).311 Females survive mainly on stored blubber reserves during lactation (up to 7 weeks), losing on average 4.55 ± 1.24 kg per day (in total up to 249 kg or 59% of their bodyweight),311 though some individuals do feed in that period.159,160,316,333 Nonbreeding females may be larger than breeding males.58 The mean weight of pups at birth is 24 kg (n = 14).311 Males range from 201 to 293 cm in length, and vary in weight both between years and over the course of the breeding season.18,147 At the beginning of the 1986 breeding season, 16 males averaged 365 kg (range 283–414 kg); by the end of the season they averaged 332 kg (range 185–273 kg, n = 14), a loss of 2–3 kg per day.18 At a neighbouring c­ olony in 1997–99, males weighed 393 ± 44.8 kg (range 314.5–465 kg, n = 28) at the beginning of the breeding season, and 348 ± 30.0 kg (range 293.5–428.5 kg, n = 24) at the end.143 At White I. (McMurdo Sound), both sexes are larger than elsewhere: females have reached 686 kg and males 554 kg.58 Distribution Weddell seals are circumpolar in distribution (Fig. 7.4). They are most abundant on the fast ice around the Antarctic coastline, and prefer to breed along perennial tide cracks in the ice.58 An unbroken ice shelf, only 18 km wide but 10–100 m thick, is enough to isolate a small breeding group at White I. from the main McMurdo population.

7 – Families Otariidae and Phocidae

Figure 7.4:  The Antarctic Ocean, showing the average outer limit of winter pack ice 1981–2010, and its retreat until 2019, reducing the habitat of elephant, Weddell, leopard, crabeater and Ross seals. (Updated by M. Oulton, from https://climate.copernicus.eu/ sea-ice-cover-june-2019.)

Weddell seals also inhabit pack ice at low densities, estimated as 2.9 per 100 km2,28 and a few breed on some of the subantarctic islands, e.g. South Georgia.192 Over-winter movements in the Ross Sea of 18 parous female Weddell seals (aged 6+ years) have been tracked by satellite telemetry.314 Seals that normally bred in the eastern McMurdo Sound travelled up to 50 km north of Ross I. (one female swam over 1500 km) and spent most

of the winter in the pack ice in the middle and northwestern parts of the Ross Sea. Heerah et al.155 tracked adult females from Dumont D’Urville at the top of the Ross Sea, and over winter the animals tended to favour enriched, warmer and less dense water masses (Antarctic Surface Water and Modified Circumpolar Deep Water) consistent with feeding primarily on Pleuragramma antarcticum. Most of the 23 weaned pups left their natal area

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by the end of February, and travelled north along the Antarctic continent coastline.50 Some pups returned to McMurdo Sound, but others were last located more than 400 km away. Pups can use the pack-ice habitat, but prefer to remain closer to the coastline than do adults. Habitat Weddell seals prefer the fast-ice environment bordering the Antarctic continent. Fast ice varies in thickness from a few centimetres to >3 m, and may extend 400 km from the coast in winter.58 They haul out on the ice surface adjacent to perennial cracks that form in the ice and along the shoreline as a result of tidal movements and wind. Breeding groups are found at predictable sites where major cracks reappear every year. Weddell seals maintain access to the surface by reaming the ice with their canine and incisor teeth, and breathing holes are kept open in the deeper cracks throughout the year. Weddell seals are deep divers, and in McMurdo Sound where they have been most intensively studied, they use the entire water column from 100 to 350 m, occasionally down to 750 m or more (Table 7.2).58,96,146,181,280,283 Female Weddell seals swimming under ice during lactation spent up to 25% of their time making putative foraging dives.160 Food Weddell seals feed mainly on fish and cephalopods, plus a few crustacea,51,58,98,125,131 but not krill.58 The predominant prey species, both by frequency of occurrence and by weight, in McMurdo Sound, at Davis Station, at Dumont D’Urville and in the Weddell Sea, is a notothenid, the bentho-pelagic Antarctic silverfish, Pleurogramma antarticum.51,58,131,262 Other important fish prey species include the pelagic notothenids (Pagothenia borchgrevinki) and benthic Trematomus spp.125 Weddell seals are renowned for hunting the large (up to 77 kg) Antarctic cod Dissostichus mawsoni, although these may not contribute significantly to their overall diet.125 Video cameras attached to the heads and backs of Weddell seals in McMurdo Sound, recorded them hunting (but not capturing) Antarctic cod at depth, and flushing P. borchgrevinki from within the platelet ice (immediately below the fast-ice surface) by expelling air bubbles.96,332 Weddell seals also kill chinstrap (Pygoscelis antarctica)325 and Gentoo penguins (P. papua).87 The largest of the yearling Weddell seals in McMurdo Sound make long, shallow dives and appear to forage on benthic species such as Trematomus spp., while smaller yearlings forage pelagically, as do adults.51

Social organisation and behaviour Weddell seals are moderately polygynous, and sex ratios at colonies vary between 2.8:1 and 8.9:1 over the course of a breeding season.147 Adult males establish and defend underwater territories in breeding areas, and residents may be displaced after repeated challenges.18,147,181 Males share breathing holes, but the volume of their individual territories may vary fivefold.143 The breeding success of males varies, with 0 to 9 offspring sired over a 4-year period.148 Males generally fast during the breeding season, but some feed opportunistically while defending their territory.149 Reproduction and development In McMurdo Sound, pregnant females arrive at pupping areas in early October;181 pups (usually singles, rarely twins) are born in October, and females stay with them on the sea ice for the first 12 days. For the next 13 days, females spend 30–40% of their time in the water.292 Lactation lasts 45 days26 and is followed by ovulation and mating in the water during December, and implantation in January or February. Pupping begins earlier at lower latitudes, e.g. in late August at Signy I., the South Orkneys (60°S) and at South Georgia (54°S).215 Spermatogenesis is initiated in August, and viable sperm are produced from October through December.296 Males reach puberty at 3 years, but are not mature and do not attend breeding colonies until 5–7 years.18 Successful (territorial) males are generally >7 years old, and can hold territories at breeding colonies until at least 13 years of age.315 Females can pup from as early as 2 years of age, but in McMurdo Sound the average age at first reproduction is 6 years (range 2–11 years), with significant costs to reproduction.136,137,153 Further north in Antarctica, the age at first reproduction is later: the average age at first sighting with a pup is 7 years at Signy I. and 8 years at the Vestfold Hills. The reproductive rate (proportion breeding) is ~0.68, but varies annually between 0.55 and 0.75 in a predictable 4–5 year cycle.319 Females continue to produce pups throughout their life (to 18+ years), with no evidence of reproductive senescence.318 Pups born to older and more experienced females have higher rates of survival.153 Females are most likely to miss reproduction within a year (1) in years when local sea ice extends further; (2) if they are the youngest and oldest individuals; and (3) if they are females with less reproductive experience.60 The ~30 seals in the isolated population at White I. produce 3–5 pups per year, have high neonatal and preparturient mortality, and

7 – Families Otariidae and Phocidae

the pups have an unusually high number of congenital deformities, suggesting a degree of inbreeding.317 Pups weigh around 24 kg at birth, double their weight in the first 10 days, and reach ~110 kg when weaned at 6 weeks old.301 Pups begin to make short dives (to 20 m and 2 min) within 2 weeks of birth. Over the first 3 months of life, the number of dives made per day, and their mean depth and duration, increase rapidly;49 by weaning at 6–7 weeks they are already capturing P. antarcticum on dives averaging 50−70 m for 3–4 min, and by 12 weeks these figures are closer to 100 m and 5–6 min.49 Pups 13 weeks old made dives averaging 116 ± 13 m and 5.6 ± 0.5 min; yearlings 200 ± 35 m, 8.7 ± 0.6 min, and adults 144 ± 83 m, 10.4 ± 2.9 min.49 Population dynamics Numbers. From aerial and shipboard surveys, the total world population has been estimated at between 750 000 and 1 000 000.97,111,181 There are ~50 000 Weddell seals in the Ross Sea, including 2500–3000 in McMurdo Sound.290 Satellite imagery has shown an increase in abundance in Erebus Bay (eastern side of McMurdo Sound) during 2004–09.189 Age and mortality. Pre-weaning mortality is low in Weddell seals (mean 0.13, range 0.06–0.22), especially among the pups of more experienced mothers aged >10 years old.153,282 Survival from 0–1 years is 0.29, from 1–2 years 0.635, and from 2–6 years 0.806, which is comparable with that of adults.154 Juvenile survival overall (0–6 years inclusive) is lower for males (0.093) than females (0.142). The minimum survival rate of adult males (≥5 years) in McMurdo Sound is 0.762, and the maximum age recorded is 22 years.318 The survival rate of adult females in general is ~0.85, but declines to 0.74 after 10 years, implying a decline in survival with age. The oldest females were aged 25.318 Predators, parasites and diseases Killer whales and leopard seals prey on Weddell seals.181 Gastrointestinal and external parasites (Table 49 in reference 176), wounds from fighting with conspecifics and tooth damage from maintaining breathing holes in ice, are common in this species.226,227 Respiratory disease is also common, and can be fatal.226 Significance to the New Zealand environment Weddell seals were once killed for dog meat to support expeditions and Antarctic bases, but killing ceased in 1986, and dogs are no longer allowed in Antarctica under

the Environmental Treaty (1992). Annex II to the Environmental Protocol (Conservation of Antarctic Fauna and Flora) required that dogs were removed from ­Antarctica by April 1994. Weddell seals are fully protected under the Marine Mammals Protection Act 1978. The Act provides for the protection, conservation and management of marine mammals in New Zealand and its territorial waters, including within 12 nautical miles of the Ross Dependency and the internal waters of the Ross Sea. Antarctic tourism continues to grow.21 In the Ross Sea region, tourists can enter the region only on ships in ­January and February, which is after the breeding season of the Weddell seal. Tourism will inevitably expand to areas where the seals breed, but the potential consequences of tourist visits to colonies during the breeding season is unknown. Visitor disturbance warrants investigation.328 All visitors to Antarctica with Antarctica New Zealand are required to follow the Environmental Code of Conduct, which requires visitors to (1) keep a minimum distance of 5 m from any animal; (2) take special care when photographing to ensure this distance is maintained; (3) avoid walking through bird and seal colonies; (4) keep noise to a minimum in the vicinity of wildlife; and (5) avoid taking vehicles within 200 m of any wildlife. Acknowledgements The pinniped chapter in the first edition was written by M.C. Crawley, and in the second edition by R.G. Harcourt. This edition was updated by R.G. Harcourt and B.L. Chilvers, and refereed by R.H. Taylor and C. R. McMahon. Citation format for this species Harcourt RG, Chilvers BL (2021) Leptonychotes weddellii. In The Handbook of New Zealand Mammals. 3rd edn. (Eds CM King and DM Forsyth) Families Otariidae and Phocidae, pp. 241–277. CSIRO Publishing, Melbourne.

Genus HYDRURGA The single species is confined largely to Antarctic and subantarctic waters.

LEOPARD SEAL Hydrurga leptonyx (Blainville, 1820) Synonyms Phoca leptonyx Blainville, 1820. Also called sea leopard.

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Description The distinguishing features of the leopard seal are shown in Plate 6 and Table 7.1. The leopard seal is built for speed. It has a long, slim body, comparatively large fore-flippers, large head, wide gape and a serpentine appearance, all of which make it easily recognisable.180 In colour, the leopard seal shades from almost black to almost blue on the flanks, with a distinct boundary between the dark dorsal and the lighter ventral coloration. The lower flanks and belly are nearly silver. The skull is very long (up to 431 mm) and the teeth are unusually complex. The molars have three prominent tubercles with narrow clefts between, and the canines are exceptionally long. Chromosome number 2n = 34. Dental formula I 2⁄2 C l ⁄1 Pm 4⁄4 M l ⁄ l = 32. Measurements A newborn pup measured 1.57 m (and weighed 29.5 kg); yearlings range from 1.6 to 2.3 m in nose-to-tail-tip lengths;47 adults reach up to 3.0 m (males) and 3.6 m (females).141 Adult weights have been estimated to vary between 275 kg and 500 kg.180 Their mass-specific blood oxygen stores are low compared with other phocid seals, resulting in lower total body oxygen stores relative to body size.183 This suggests that the physiological performance of diving leopard seals is inferior to that of other phocids, and this is supported by hematocrit, hemoglobin, heart rate, and respiratory rate data collected on captive leopard seals.338 Distribution Leopard seals live throughout the pack ice from 50 to 79°S and southwards to the Antarctic continent (Fig. 7.4). They are found year round on Heard I.,47 gathering in large numbers (100+ animals) in midwinter (July). They are seasonal visitors to other subantarctic islands, e.g. on South Georgia between April and November,331 and especially to Macquarie I. from July to November.134,278 In winter, young leopard seals are often seen hauled out on the South I. of New Zealand, in Tasmania and in mainland Australia as far north as Sydney and off Western Australia.220 Food Leopard seals are shallow divers who feed directly under the sea ice on swarming prey or use a sit-and-wait ambush strategy for larger prey (Table 7.2). They are primarily nocturnal divers that synchronize their foraging activities

with the diel vertical migration of krill, and they forage at night, when krill or their predators (penguins and other seals) are closest to the surface. Leopard seals eat krill (~30% of the diet), penguins (26%), fish (13%), seals (8%), cephalopods (8%) and an assortment of marine organisms (15%).138,255 The precise diet depends upon location and time of year.139,210,331 Different hunting tactics seem to be favoured by particular individuals, and they are the only phocid seal in which both sexes frequently hunt warmblooded prey.276 Leopard seals frequent the ice floes and waters adjacent to Adèlie penguin rookeries, and are adept at catching penguins after underwater pursuits or as they fall back into the water after missing their footing on the ice.260 They will also stalk penguins under thin ice, breaking through with their heads to seize them, and will ambush them at the ice edge, either as they return from or depart to sea.276 Estimated rates of penguin predation can be high, e.g. at Cape Crozier, 2.4%249 or 5%260 of the Adèlie colony within a season; and at Prydz Bay, 2.7% of a population of 215  000 penguins in 1993.276 Predation appears to be a function of penguin density, with seals appearing only when penguin traffic exceeds 250 birds per hour.1 Leopard seals can also impose significant mortality on fur seal populations. At Elephant I. (South Shetland group), leopard seals prevented the population growth of at least one Antarctic fur seal colony.36 Social organisation and behaviour The highest numbers, including juveniles, gather along the edge of the pack ice. Adults are solitary and widely dispersed across vast areas of pack ice,28,276 so they coordinate their spacing and mating behaviour by underwater vocalisations. Calls are of low to medium frequency (300– 3500 Hz) and long in duration.277 The lowest frequency call is particularly powerful and resonant, and can be heard at the surface and felt through the ice.92 At least 12 distinct call types have been associated with different behaviour patterns. Six local call types, heard throughout most of the year, were associated with close-range agonistic interactions; six broadcast call types, produced by lone seals, were made by females when sexually receptive, and by mature males during the breeding season.276 Reproductive behaviour. Pups are born between October and mid-November. Mating behaviour has been described in captivity,277 but has never been seen in the wild. Presumably mating follows 3–4 weeks after parturition.291

7 – Families Otariidae and Phocidae

The shifting environment of the pack ice prevents males from monopolising females in the manner of Weddell or elephant seals, and the degree of polygyny is probably low. Reproduction and development Males are sexually mature at 4–6 years. Females ovulate in their second year, and may become pregnant in their third year;141 pups are born in November.47,48,135,299 Population dynamics Numbers. In 1999–2000, the international Antarctic Pack Ice Seals Program conducted simultaneous surveys for pack ice seals around the Antarctic continent, and estimates were found to have wide confidence limits due to their poor sightability.300 Nevertheless, for east Antarctica the two estimates for leopard seals were 7300 or 12  100 (95% CIs of 3700–14 500 and 7100–23 400, respectively),300 and for the Ross and Amundsen seas ~15 000.24 Age and mortality. Males may reach 16 years of age and females may exceed 13 years.191 The pup mortality rate in the first year is ~25%. Predators, parasites and diseases Leopard seals have no known predators. The few known parasites are listed in Table 49 in reference 176. Significance to the New Zealand environment Leopard seals have never been systematically exploited, and it is unlikely that they will be. They are included under the Marine Mammals Protection Act 1978, which provides for the protection, conservation and management of all marine mammals in New Zealand and its territorial waters, including within 12 nautical miles of the Ross Dependency and the internal waters of the Ross Sea. Acknowledgements The pinniped chapter in the first edition was written by M.C. Crawley, and in the second edition by R.G. H ­ arcourt. This edition was updated by R.G. Harcourt and B.L. Chilvers, and refereed by R.H. Taylor and C.R. McMahon. Citation format for this species Harcourt RG, Chilvers BL (2021) Hydrurga leptonyx. In The Handbook of New Zealand Mammals. 3rd edn. (Eds CM King and DM ­ Forsyth) Families Otariidae and Phocidae, pp. 241–277. CSIRO Publishing, Melbourne.

Genus LOBODON The sole species of this genus, L. carcinophagus, confined to the Antarctic, is probably the most abundant seal in the world.

CRABEATER SEAL Lobodon carcinophagus (Hombron & Jacquinot, 1842) Synonym Phoca carcinophaga Hombron & Jacquinot, 1842. Description The distinguishing features of the crabeater seal are shown in Plate 6 and Table 7.1. Crabeater seals are predominantly dark brown with lighter brown patches dorsally, grading to blond ventrally. The flippers are dark. Individuals gradually lighten with age to a uniform blond; hence the old name ‘the white Antarctic seal’.339 Crabeater seals are lithe in appearance, and fast and agile on snow and ice. The canines are small but the molars are extremely complex, each with several pronounced tubercles separated by deep spaces.178 The main cusps of the upper and lower rows fit between one another, and the occlusion is perfect. They function as sieves to strain invertebrates, especially euphausiids (krill), out of the water. Chromosome number 2n = 34. Dental formula I 2⁄2 C 1⁄1 Pm 4⁄4 M 1⁄1 = 32. Measurements Adult males and females reach up to 2.34 m nose-to-tail length by 10 years.196 Mean adult mass varies slightly between years, with adult males averaging 203, 192 and 208 kg, and adult females 225, 205 and 219 kg for 1975, 1976 and 1977, respectively. Newborn pups measure 138 cm (standard body length) and weigh 30 kg.196 Distribution Crabeater seals live almost exclusively on the Antarctic pack ice (Fig. 7.4), but in summer some travel south to the Bay of Whales (Ross Sea, 79°S)205 and McMurdo Sound (77°S) and even, for unknown reasons, far inland. ­Carcasses have been found in the Dry Valleys and on the Ferrar ­Glacier at 1100 m altitude,339 and in December 1966 a live male pup was found 113 km from open water on the ­Crevasse Valley Glacier (76.77°S 145.48°E).179 Crabeater seals are also seen occasionally in New Zealand, T ­ asmanian, southern Australian and South American waters.281

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Habitat Crabeater seals inhabit the pack ice and the upper layers of the southern ocean. They are capable of diving for at least 15 min, up to 225 times a day, and occasionally to depths of >500 m, but 80% of dives are short (225 m, the mean dive depth was 100 m and the mean duration 6.4 min (Table 7.2),25 suggesting that this animal was diving to midwater depths and not to the bottom. When Ross seals and crabeaters forage in the same areas, Ross seals make many more deep dives for fish and cephalopods, whereas crabeaters hunt krill nearer the surface.25,293 Food Ross seals eat mainly fish (particularly Pleuragramma antarcticum), cephalopods (Psychoteuthis glacialis and Allouroteuthis antarcticus) and a few krill.281,293 In one sample, the proportions of these items were cephalopods 64%, fish 22%, and other invertebrates (including some krill) 15%.255 Social organisation and behaviour Most Ross seals are seen alone, and 1.5  km, whereas 12 of 73 (16.4%) movement records for males were between 1.5 and 4 km.288 Home ranges often overlap, particularly between sexes,2,261,288,289 but many individual stoats have separate core ranges that do not overlap.456 The size, length of tenure and pattern of use of home ranges depend largely on the density and distribution of prey. In beech seeding (mast) years, higher numbers of potential prey (mice, rats, and birds) are quickly followed by higher numbers of stoats. Then they either live on smaller home ranges289 or are non-territorial.2 Where food is superabundant, stoats maintain very small ranges, e.g. at a colony of Hutton’s shearwaters in the alpine zone of the Seaward Kaikoura Range during the nesting season.87 In spring, some males travel more widely than usual in an intensive search for females,119,391 but usually return to their core home range.261 In northern Fiordland in the post-seedfall summer of 1979/80, on two straight lines of live-traps 400 m apart, adult stoats of both sexes were well spaced out (~ one per

2–4 km), and each individual tended to visit only the  same  two to five adjacent traps (spanning a total of 0.4–1.6  km).207 The daily probability of first capture (0.17) was the same for all stoats, regardless of sex or age, but depended in part on opportunity to find a trap as well as on individual trap response. The probability of recapture varied between age and sex classes. Young of the year males were the least liable to develop trap shyness, while the recapture probability of young of the year females halved after first capture.201 Stoats ranged further along a 38-km transect of beech forest with traps at 1 km spacing in southern Fiordland during the crash summer of 2000/01, where two females moved 2.2 and 6 km along the line, and eight males moved an average of 2.9 km.342 Dens. Stoats do not make their own dens, but take over those of other animals. In forest habitat, den sites may include holes up the trunks and in roots of trees;288 in open country, in rabbit burrows, piles of logs, ditches, under sheets of iron, and in isolated patches of scrub.100,127 In the Eglinton Valley, of 29 stoat dens found, 22 were obvious holes in the ground under tree roots, three were up trees, and four were in the middle of a grass flat.289 In a braided riverbed in the McKenzie Basin, stoats consecutively shared dens (mostly rabbit burrows) both with other stoats and with ferrets.100 The long, thin shape and short fur of stoats make them liable to excessive heat loss while resting,38 so a well-insulated nest is important even in the mild climate over much of New Zealand, and is an essential condition of survival in colder areas.191 Female stoats move about less during the breeding season,379 and females with small young are sedentary except when forced to shift their young between den sites.289 Voice. When nervous, a stoat makes a low hissing sound. When extremely frightened (e.g. if caught in a trap, or threatened by a dominant or a larger predator), this intensifies into a loud wailing squeal. Friendly encounters between family members or mates are accompanied by an excited, highpitched trilling. A subordinate individual encountering but not distressed by a dominant gives a submissive trilling sound, which helps to mollify the reaction of the dominant. A sharp explosive chirp or shriek is a defensive threat, very effective against other stoats114 and unwary humans. Communication. Scent-marking behaviour is well known but not well understood. At the very least, scent marks convey information on social and reproductive

9 – Family Mustelidae

Table 9.5:  Home ranges of New Zealand stoats.

Season

Sex

n

Home range (ha ± s.e.)

Beech forest, 1990/91

Su/Au

M F

3 4

93 ± 7 69 ± 8

Beech forest, 1991/92

Su/Au

M F

4 5

Beech forest, 1996

Sp

M F

North I. podocarp forest

W

Ungrazed grassland

Habitat, year

Comments

Reference

Post-seedfall year, mice abundant

289

206 ± 73 124 ± 21

2 years after last mast year, mice scarce

288

4 7

223 ± 45 94 ± 13

18 months since last seedfall, mice scarce

M F

6 3

65 ± 15 40 ± 11

456

Sp Au

M M

3 3

110 ± 28 158 ± 31

265

South I. podocarp forest

Sp Au Wi Sp Su Au

M M F F F F

8 2 2 5 3 4

256 ± 38 145 ± 35 123 ± 6 81 ± 20 75 ± 67 44 ± 18

261

Alpine tussock

Sp Su Su

M M F

2 4 2

48 ± 0.2 16 ± 2.3 9 ± 0.1

Braided riverbed

Sp Au Sp Au

M M F F

13 13 3 7

313 ± 63 185 ± 28.5 127 ± 78.9 116 ± 21.2

Alpine tussock and beech forest

Su Su

M F

7 4

127 ± 30 50 ± 7

Most Su–Au

M F

9 2

109 ± 29 81 ± 31

Trounson Kauri Park

Within a nesting colony of Hutton’s shearwaters

2

87

100

Within the Takahe Special Area

398 141

Sp, spring; Su, summer; Au, autumn; Wi, winter; M, male; F, female; n, sample size. Mean home range is in hectares ± 1 s.e., calculated by the minimum convex polygon method.

status, and probably also individual identity, so allowing subordinate individuals to avoid damaging conflicts with other stoats. By contrast, and contrary to expectations, scent marks deposited by ferrets and cats (the dominant members of the New Zealand predator guild) trigger cautious approach and inspection by stoats, and changes in their foraging behaviour, both in captive trials and in the field.137 This reaction by a stoat, a subordinate member of the guild (a mesopredator) can be interpreted as ‘eavesdropping’, providing information on the locations of both risks and potential resources. Stoats mark their home ranges with scent from two types of glands, which have different chemical compositions. The large anal glands under the tail produce a strong-smelling, thick yellow fluid containing several sulphurous compounds, identified from New Zealand

material as mixtures of thietanes and dithiolanes.35,83 The principal components can now be synthesised in the laboratory. The scent produced is individually distinct,121 and is deposited, by a characteristic ‘anal drag’ action, at strategic sites throughout the home range; it signifies ownership of the ground by a particular individual. Odour from the small scent glands in the skin is deposited by ‘body rubbing’, especially in response to an encounter with another stoat or its scent marks. The skin gland secretion contains mainly proteinaceous lipophilic compounds carrying smaller molecules of high volatility,121 and signifies a threat to intruders. Dominant individuals mark in both ways more often and more vigorously, and mark over places previously marked by other stoats; subordinates show signs of fear when scenting strange marks.114

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Reproductive behaviour. Males search for females very actively during the breeding season, roughly from ­September to November, but they do not establish even a temporary pair bond, and take no part in the rearing of the young.115 Dominant males can expect to invade the home range of any female they can find, so can achieve most matings by searching a large area.119,389 Younger males remain on their home ranges,where they have a chance of getting at least one mating by being nearby when a resident female comes into oestrus. Genetic evidence of multiple paternity165 suggests that the two strategies need not be mutually exclusive. The male serves both the breeding female and her precocious juvenile females in the den.424 The lack of pair bonds, the variable mating strategies of males of different social status, and the rapid turnover of the population all reduce the chances that any given male is serving his own young, but the levels of inbreeding within local populations have not been tested. On Kāpiti I., where a pregnant female arrived and gave birth to a son and daughter, both the mother and daughter were pregnant when caught, showing that inbreeding is not avoided when other options are unavailable.340 Females aggressively reject any male until they reach full oestrus, when the vulva becomes enlarged and its orifice moist and reddened. Courtship is brief, but copulation vigorous, prolonged (2–20 min), and frequent (two to five times an hour),280 because ovulation can be induced only by coitus. All attempts to stimulate ovulation by injection of gonadotropins have failed.151 Males have two periods of intense sexual activity: ­September–October, when the adult females that have failed to rear a litter first come into oestrus; and October– November, when the precocious juvenile females and their mothers become receptive. Adult males are apparently able to serve the juvenile females without damaging them, even though they are so small. One 17-day-old captive female, only 112 mm long, weighing 18 g (13% of the weight of the mother, and 6% of that of the adult male), and blind, deaf, helpless and almost immobile, was mated for 1 min, and in the following season produced 13 kits and fed them successfully.424 Reproduction and development The testes are simple, about the size of a pea in the mature adult. The urethra lies in a groove on the underside of the baculum, a small bone attached to the pelvis at its proximal end, which acts as a rigid support during the

vigorous copulations necessary to ensure induction of ovulation. The development of the baculum is controlled by androgens,452 so the distinctive proximal knob characteristic of adults does not develop in young or castrated animals. The uterus is a simple U-shape, and in fresh material the blastocysts are visible via transmitted light from 38–40 days after mating until implantation,335 which in New Zealand means from the end of December to early August. The flattened ovaries have obvious corpora lutea of delay, visible as yellow dots, for 9–10 months of the year.208 Each represents one ovum released at ovulation, and each persists until spring, regardless of the fate of that ovum, and then degenerates. Successive generations of corpora lutea do not overlap, since those of one set are replaced a few weeks after the young are born by a fresh set representing next year’s litter.208 Since the corpora lutea are found in females of all ages for most of the year, they provide a simple means of estimating potential fecundity, although the actual number of young born may be very different.184 Age at puberty. Young males do not mature until 10 months old, i.e. in July and August of the season after that of their birth. Young females are extremely ­precocious and are reproductively mature in October–­November, as unweaned nestlings only 3–5 weeks old.335,424 Young of both sexes continue to grow in body size after puberty. The young females are already carrying blastocysts, but these demand little energy to maintain, and further development is delayed until well after the young females have completed their own growth in March–April – a great advantage for young females dispersing to new areas with no potential mates, e.g. stoat-free islands. Young males reach adult size after a sudden, substantial spurt of growth in September and October. Seasonal cycle. The testes of males of all ages begin to enlarge in July, reach full size in October, and regress slowly from December to a minimum in May.208 The period of increase begins after the winter solstice, several weeks after the onset of spermatogenesis, and is accompanied by high levels of plasma testosterone.150 Fully fertile adult males may be found from August to February. In males, faecal testosterone excretion is higher during the breeding season (September–January) than outside it (February–August), matching the development of the testes.220

9 – Family Mustelidae

Females of all ages caught between December and August inclusive are almost always (>99%) in the preimplantation phase of pregnancy; they carry the small (0.4–0.6 mm) corpora lutea of delay, and support a set  of  eight to 10 diapausing blastocysts in a quiescent (0.05–0.15 g) uterus.184 In July both the corpora lutea and uterus begin to enlarge in preparation for implantation, and between August and October they reach 0.9–1.4 mm and 0.15–0.36 g, respectively. Visibly pregnant and postpregnant (lactating and/or in oestrus) females may be found only in September and October, and by the end of November almost all females are already fertilised and carrying a new generation of corpora lutea of delay. The ecological explanation for delayed implantation has been extensively debated, though there is a general consensus that it is related to optimising the seasonal timing of both mating and giving birth, usually exhibited in environments with high inter-season variability.190,233,338,388,411 The seasonal cycle in both sexes is controlled by day length. The onset of spermatogenesis and the implantation of the blastocysts both tend to be later in the far south of New Zealand (44–45°S) by a short period (~10 days) corresponding to the lag in the date at which the southern regions reach the critical day length that sets off these processes in July–August.208 Hence, most North I. litters are born from late September to early October, and most South I. ones from mid- to late October. The period of oestrus is brief and can be detected from vulval swelling confirmed by faecal oestradiol levels.220 The males are very efficient at finding receptive females, so very few oestrous females are ever caught. In captivity, unmated females remain on heat for months, although they do not ovulate and their ovaries contain no corpora lutea.208 Artificial reproductive technologies have been investigated for stoats in New Zealand, with some progress in enabling sperm storage, and the in vitro culture and development of stoat blastocysts, though more work is required on several fronts to enable successful artificial reproduction.220 Gestation. From fertilisation to the onset of delay (~2 weeks), the zygotes develop only as far as the blastocyst stage and then float free in the uterus for 9–10 months. The blastocysts distribute themselves evenly between the two horns of the uterus and are often fewer than the number of corpora lutea.208 The following spring, they implant in the normal way, and the embryos develop to full term in ~4 weeks. The approximate date on which a

given litter would have been born can be estimated by calculating t (a negative value, days before birth) from the mean weight of the embryos (W) by the formula t = 3 (√W/0.063) + (16 – 40), and is later in the South I. than in the North I.208 Female stoats may be caught in closely spaced traps as often as males in summer and autumn but less often in the rest of the year, especially in spring. Pregnant females, the most difficult to catch of all, comprised only 13 of >1600 stoats collected year-round over 4 years in the 1970s.208 In any given place or year, the number of viable embryos is adjusted to prevailing food supplies (see below), but the general average is usually 8–10. The mean number of embryos in the 1970s collection was 8.8 per set (range six to 13), but in at least five sets there were some embryos being reabsorbed: in one female, only one of the eight embryos was viable. A collection in the 1960s127 recorded three pregnancies with seven, 12 and 12 embryos; another in the 1990s, four pregnancies with six, eight, 10 and 10 embryos.244 In Britain, eight of 305 female stoats were pregnant with 7–10 embryos (mean 9.0).249 Birth and development. The young weigh ~3–4 g at birth, are blind, deaf and toothless, and are covered with a fine whitish down. By 14 days they develop a prominent but temporary brown mane.212 While the female is away, very young kits (under 5–7 weeks old) are not able to maintain their own body temperature; they huddle together, and if the temperature in the nest drops below ~10–12°C they go into a temporary, reversible cold torpor, and their pulse and breathing slow down.394 They attain full control over body temperature when their fur is fully grown, at ~8 weeks old (the black tail tip appears at ~6–7 weeks). Milk teeth erupt at 3 weeks, solid food is taken from 4 weeks on, the eyes open at 5–6 weeks (females first), and lactation stops after 7–12 weeks.212,280,335 The permanent carnassial teeth, P4 and M1, are last in place, at ~4–5 months. At Manaaki Whenua Landcare Research at Lincoln, the first captive-bred young produced in New Zealand appeared in 2001.312 The typical prey-killing behaviour is instinctive, but improves with practice from first attempts at 10 weeks to full maturity at ~12 weeks. The female rears the young alone, and hunts for and with them from the time they are active and weaned but still dependent, at ~6–8 weeks, to the time the families break up, when the young are ~12–14 weeks old.

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Females and their young may be seen moving about in family parties (groups of up to 7+) from late October, when North I. young first venture out of the nest, until early February, when the last of the South I. litters disperse.186 Young of both sexes are capable of astonishingly rapid dispersal. In Fiordland in December–January 1979/80, seven young males marked with eartags travelled between 6 and 23 km within a few weeks of independence,207 and one young female tagged in the Eglinton Valley on 20  December 1990 was found in a kill-trap at Burwood Bush (65 km away) on 13 January 1991.289 Young of the year can be caught in traps from mid- to late November, but most often from mid-December to February. Population dynamics Stoats have short lifespans and high, very variable rates of birth and death. Their populations are naturally unstable, and their density and distribution are controlled primarily by food.188 This combination of characters gives them considerable resistance to human management.18,209,249 Productivity. Delayed implantation means that productivity (number of young born) cannot be related to fecundity (ovulation rate). Maximum potential fecundity is set during the mating season of one year, while productivity cannot be realised until the following year, when conditions may be very different; this flexibility makes realistic population modelling difficult without age-, year- and sex-specific survival data.213,449 Resorption and nestling mortality cut down the potential litter size by 0–100% of

ova released, depending on food supplies during the season of implantation and lactation.449 In the 1970s the mean ovulation rate (indicated by the number of corpora lutea) in 439 females was 10, range 3–20, with an inverse correlation between the number of corpora lutea in the two ovaries of one individual. The  average tended to be slightly higher in females of all  ages fertilised in years when mice were very abundant.184,208,339 The number of young born is closely related to food supplies in spring (Fig. 9.1). This correlation is probably quite general, but can best be demonstrated in beech forests after a good mast year.216 During the winter following a seedfall, mice increase greatly in density; in the early summer (8–9 months after the fall), huge numbers of young stoats appear.97,213,316,448 The increase in productivity to match resources can be made only by reduced intrauterine and nestling mortality, not (as in many other mammals) by additional productivity, because the maximum potential number of young born is already fixed at ovulation, in the previous year. In poor years, mortality increases at every stage from implantation to weaning; many females resorb some of their embryos, or even all of them, and others bear their young but fail to rear them.184 These failures happen most often in beech forests in the ‘crash’ years after a seedfall. In post-seedfall summers in Fiordland, no young stoats were among 37 caught in 1991/92289 or among 76 caught in 2000/01.342 Less disastrous shortages are met with proportionately less drastic measures.216

Figure 9.1:  Generalised model of the multi-annual beech mast cycle in South I. Nothofagaceae forests, and the usual responses of wild house mice and stoats,196 based on data from three populations regularly sampled through two successive masting events by removal trapping.189 The decline of stoats during Year 2 may be more gradual in undisturbed populations.342

9 – Family Mustelidae

The average rate of loss before parturition has been estimated at ~13% of blastocysts failing to implant, and ~12% of embryos resorbed.184 In any one year the extent of this process can be roughly estimated from the ratio of young to adult stoats caught in summer. After a good year, young of the year comprise 80–90% of the catch; in the worst years, 0–10%.216,339 Density. Estimates of absolute density are rare, because the conditions for determining it are hard to meet (e.g. labour-intensive live-trapping, clear definition of area sampled, and vital assumptions concerning immigration, emigration, and equal catchability of all individual stoats present). The best opportunity to make a total count is during a trap-out operation on an island, and the figures can be surprisingly high. Sixteen stoats were removed from 514 ha on Te Kakahu (Chalky I.), and 22 from 1130 ha on Anchor I., both rodent-free,111 corresponding to absolute densities of 3.1 per km2 and 1.9 per km2. During the Resolution and Secretary islands eradication programs, it is likely that nearly all stoats were trapped in the initial knockdown or were identified by tooth aging as having been present at that point.433 On rodent-free Secretary I. (8140 ha), at least 114 stoats would have been present at the start of trapping (1.4 per km2), and on Resolution I. (20 860 ha), which has mice although trapping was done in a low mouse density year, at least 324 stoats would have been present (1.55 per km2). The differences in these stoat population densities may relate to differences in prey availability.290 All of these killtrapping operations were conducted in winter at the annual stoat population minimum. Near Maruia, traditional live-capture–mark–recapture methods gave absolute densities of 4.2 stoats per km2 (95% confidence intervals, C.I. 2.9–7.7 stoats per km2) in summer 1996, 8–9 months after a significant beech seedfall in autumn 1995; and 2.5 stoats per km2 (C.I. 2.1–3.5 stoats per km2) in late winter 1996, 15–16 months after the seedfall.8 A newly developed method uses hair tubes baited with rabbit meat to collect samples of hairs from stoats, from which individual DNA profiles can be extracted.146 In the first trial, 30 different stoats were detected on an area of 9 km2 (this may not equate to 3.3 stoats per km2 when a boundary strip is added). On a 750 km2 peninsula in Lake Waikaremoana, 65 stoats were removed in 3 months during a peak year (9 per km2), so a model of the consequences of stoat predation on kiwi in that area23 took the normal range of summer stoat densities to be 2–10/km2.

At a breeding colony of Hutton’s shearwaters, abundant food permitted much higher local density, at least temporarily (~17 stoats per km2 in summer).87 In the Okarito Forest Kiwi Sanctuary (10  000 ha), two consecutive and widespread rimu masts permitted escalating numbers of ship rats (a favoured food of stoats); 1950 stoats and >10 000 rats were caught between 2001 and 2004.283 Relative density can be estimated from standardised trap-lines, although changes in the protocols used by different operators make long-term comparisons difficult. In beech forest in the 1970s, there was a regular seasonal variation in average capture rate, from 3 months or from traps not inspected daily show the same pattern97 but are not directly comparable with these.215 Stoats are often patchily distributed in the landscape.342 In Pureora Forest Park (FP), density indices were consistently high in one area (up to 11 C/100TN) but much lower in two nearby areas.292 In a South I. braided river valley, live-trapping indices ranged between 6–8 C/100TN in March and 0.5–2 C/100TN in September over a 2-year period.100 Different forms of relative density indices (live capture rate and tracking tunnel indices) are usually well correlated, and one attempt to calibrate relative density figures against known density suggested that C/100TN indices are normally reliable.117 Neither conclusion necessarily applies when prey are very abundant.8,87,215 The additional numbers of stoats caught in summer are almost all newly independent young,184 and in a mast year may, for very short periods, reach extraordinary figures; e.g. in the Eglinton and Hollyford Valleys during the week 1–4 January 1980, indices of 18.1 and 23.2 new captures per 100 live-trap-nights were recorded,207 but the means for the month were 8.2 and 10.7 respectively, and for the 3-month summer season, 5.5 and 6.2 C/100TN. If trapping continues over the winter, normal low density may be restored by the following spring, but, if not, numbers can remain higher than normal for another summer.289,342

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The three-stage correlation between seedfall and mouse density and between the density indices for mice and stoats is well established in beech forests189,316 and the increase in numbers of stoats in post-seedfall summers is obvious enough to be noticed by casual observers, e.g. visitors to national parks.186 At Pureora FP, a non-beech forest/pine plantation systematically sampled over 5 years, stoats were at low density (equivalent to, or less than, in a non-seed year in a beech forest) throughout 1983–87.204 In the Orongorongo Valley, stoat numbers increased after a seedfall in 1971, but not after subsequent seedfalls.128 In non-forest habitats, variations in density of stoats may be traceable to fluctuations in density of rabbits. For example, stoat populations in Britain were drastically reduced for 15–20 years after myxomatosis almost eliminated rabbits in 1953–56, recovered until the 1990s and have since fluctuated.248 Competition. Numbers and distribution of stoats are significantly reduced by interference competition from larger predators. There is a negative correlation between the distributions of stoats and cats on small (71 000 km over 50 years found steady increases in rabbits (attributed to the end of subsidised control in the mid-1980s) (pp.  143–144): cats and mustelids followed until the 1990s, and have declined since then.130 In competitive interactions between stoats and weasels, stoats are always the dominant partner. Studies investigating the segregation of mustelids found clear dominance of stoats over weasels. In optimal habitats where stoats are more common, weasels are rare or absent, except in less productive areas.120 Sex ratio. At birth, 1:1,424 but trapping samples the sexes unequally, and variably by season. From December to May, monthly catches comprised 43–53% males (n = 939 stoats), rising through early winter (June, 58% of 95; July, 64% of 95) to 70–77% in August to November (n = 335),208 largely due to seasonal changes in the activity patterns of the two sexes (see above). Closer trap spacing favours females (2 km).182 This difference arises partly because males tend to occupy larger home ranges than females, and so have more opportunity to find traps; partly because the heavier males are more likely to set off traps; and hence the probability of capture is lower for females than for males.22 Sex ratio was not significantly different after beech seedfalls in Fiordland compared with non-seed years (40–63% males in both), implying that the huge variations in density of mainland populations had no effect on the sex ratio of stoats sampled by conventional means.207 The real sex ratio of an undisturbed mainland population is unknown, although the individuals most often recaptured or encountered are always males.201 On Resolution and Secretary islands the true sex ratio (based on nearcomplete censuses via kill-trapping) was significantly female-biased (1 male:1.71 females on Secretary I., n = 114, and 1 male: 3.39 females on Resolution I., n = 303).433 On both of these islands, stoat diet at the time of capture consisted of >90% invertebrates.290 The lack of large prey to sustain the larger males may explain the unusually high male mortality rates. Continual trapping can also

9 – Family Mustelidae

select for the survival of trap-savvy older breeding females, which can become almost untrappable.375

lines visible in these sections, confirmed as annual from New Zealand material, are laid down during winter.149

Age determination. The ages of living stoats can be estimated only in spring and summer, and even then only into two classes (adult and young of the year).195,207 Adult females have visible nipples, large if they have borne young, small if they have not; the nipples of young females are almost invisible. It is very difficult to distinguish between first year females and adults that have never bred. Over 99% of adult males have enlarged testes in summer, but no young males. These distinctions visible in the field have been checked from the teeth, and found reliable.117,149,342 Bodyweight is not a helpful clue after late December, since young females reach 97% of adult weight by February, and young males 80%.208 The skulls of juvenile stoats are distinguishable in both sexes until mid- to late January, from their thin chalky bones, a rounded cranium with undeveloped mastoid and occipital condyles, and clearly visible nasal sutures. The sagittal crest is a wide-open V-shape, and the ratio of interorbital to postorbital widths averages 30°C to 50% of their annual diet in the 1980s (Table 14.12). Although another 102 food items were eaten, only 18 of these formed >0.5% of the diet. Much of the diet was obtained from fallen plant material, especially supplejack fruit and the cast, often yellowed, leaves of broadleaf. Although supplejack was the second-most-important

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125

KILOMETRES

Figure 14.12:  White-tailed deer distribution in New Zealand based on data collected up to 2007.143

14 – Family Cervidae

Table 14.12:  Main foods (annual mean percentage dry weight) identified from the rumen contents of 160 white-tailed deer on the north and east coasts of Stewart I./Rakiura.380 Only items comprising >0.5% of diet are listed. A total of 104 foods were identified to species (n = 80) or genus (n = 24). Due to rounding, the total is not 100.0%.

Taxa

% of diet

Trees and shrubs Griselinia littoralis

Taxa

% of diet

Climbers Ripogonum scandens – fruit

11.3

4.4

R. scandens – leaves

4.6

Coprosma foetidissima

4.0

R. scandens – stems

2.7

Weinmannia racemosa

3.3

Seaweeds

1.3

Metrosideros umbellata

3.1

Fungi

1.1

Pseudopanax crassifolius

2.4

Ferns

Carpodetus serratus

34.6

Pittosporum spp.

1.1

Dicksonia squarrosa

2.1

Fuchsia excorticata

0.8

Blechnum fluviatile

1.4

Podocarpus ferruginea

0.7

Other ferns

3.3

Coprosma lucida

0.6

Grasses and sedges

2.6

Raukaua simplex

0.6

Herbs

1.2

Pseudopanax edgerleyi

0.6

Minor plant foods

5.8

Other tree/shrub species

2.1

Unidentified material

5.0

food in the north-east, it was not eaten in winter in the more southern Port Pegasus area, where deer ate more of the less-preferred shrub, fern and grass species.369 Whitetailed deer often eat seaweed on Stewart I./Rakiura.35 In the Wakatipu area, browsing patterns in the 1970s indicated a diet mainly of mountain beech (Fuscospora cliffortioides) seedlings, but also included some silver (Lophozonia menziesii) and red beech (F. fusca) and small amounts of palatable but very scarce species such as broadleaf, Pseudopanax spp. and Coprosma spp.50 River flats provided indigenous and introduced grasses and herbs, with occasional matagouri (Discaria toumatou); deer also grazed the improved grasslands on farms. Social organisation and behaviour White-tailed deer live in small family groups, usually made up of does and their offspring, whereas the bucks live separately for most of the year. In North America, the average home-range size for non-migratory white-tailed deer varies between 71 and 342 ha, while migratory populations move 10–15 km between seasonal ranges.321,491 There, most young males, and ~20% of young females, disperse up to 170 km.362 On Stewart I./Rakiura, between 1994 and 2007, tracking of a few (1 pair of incisors, not chisel-shaped; diastema either absent or shorter than molar row���������� 6 5. One pair of incisors in upper jaw [Rodents]������������������ 22 – Two pairs of incisors in upper jaw [Lagomorphs]��������� 25 6. Crowns of molars flat, with enamel ridges��������������Horse – Crowns of molars with cusps��������������������������������������������� 7 7. Lower canines tusk-like, angular in cross-section; I3 widely separated from I2������������������������������������������������������������������� Pig – Lower canines rounded or ovate in cross-section; I3, if present, close to I2���������������������������������������������������������������������������������� 8 8. Length of skull > 25 mm����������������������������������������������������� 9 – Length of skull < 25 mm [Bats]���������������������������������������� 26 9. Canines prominent above and below; tympanic bulla inflated; mandibular condyles transversely elongated [Carnivores]������������������������������������������������������������������������� 10 – Canines not prominent; tympanic bulla incomplete; median spine projecting behind posterior edge of palate���������������������������������������������������������������������� Hedgehog 10. Length of skull < 180 mm; post-canine teeth 3–7, very variable in shape and size [Land carnivores]����������������� 28 – Length of skull > 180 mm; post-canine teeth 6; rather uniform in shape and size (large central cusp, small anterior and posterior cusps) [Otarids]���������������������������31 11. Masseteric fossa shallow, masseteric canal absent; molars with separate cusps�������������������� Brushtail possum

– Masseteric fossa deep, masseteric canal present; molars transversely ridged������������������������������������������������ 12 12. 11 wider than 13���������������������������������� Brush-tailed rock wallaby – 11 narrower than 13���������������������������������������������������������������������������������13 13. Ml larger than M2����������������������������������������������������� Swamp wallaby – Ml smaller than M2��������������������������������������������������������������������������������� 14 14. Groove on 13 on rear two-thirds of tooth��Dama wallaby – Groove on 13 about central����������������������������������������������� 15 15. Rear edge of 13 curved���������������������������� Bennett’s wallaby – Rear edge of 13 angular������������������������������������������������������ 16 16. Groove on 13 posterior to midline������������� Parma wallaby – Groove on 13 anterior to midline��� Black-striped wallaby 17. Males with solid, bony, permanent bony pedicle supports deciduous antlers in season; upper canines sometimes present [Cervids]�������������������������������������������� 32 – Males, and often females, with permanent horns (keratin sheath on a bony core); upper canines absent [Bovids]�������������������������������������������������������������������������������� 18 18. Palatine bone occupies about half of space between molar rows; pedicles directed sideways; parietal and occipital bones at acute or right angles to frontal bone��������������������������������������������������������������������������������Cattle – Palatine bone occupies about one-third of space between molar rows; pedicles directed upwards or backwards; parietal and occipital bones at obtuse angle to frontal bone [Caprinids]������������������������������������ 19 19. Horn cores perpendicular to cranium�����Alpine chamois – Horn cores sweep backwards from cranium����������������� 20 20. Lambdoidal suture straight, coronal suture angled; shallow lachrymal fossae present�������������������������������Sheep – Lambdoidal suture angled, coronal suture straight; no lachrymal fossae������������������������������������������������������������ 21 21. A line through the centres of the orbits passes well clear of posterior edge of nasal bone; ear canal directed backwards������������������������������������ Himalayan tahr – A line through the centres of the orbits approaches or touches posterior edge of nasal bone; ear canal directed sideways������������������������������������������������������������Goat 22. Maxillary tooth row > 5 mm long [Rattus]�������������������� 23 – Maxillary tooth row < 5 mm; upper incisors have notch in wearing surface; M l with 3 roots; M3 much smaller than M2�������������������������������������������������������������� House mouse 23. Cranium with rounded margins (temporal ridges widely curved); length of parietal bone along its outer edge exceeds width of cranium���������������������������������������� 24 – Cranium with straight margins (temporal ridge parallel); length of parietal bone along its outer edge same as width of cranium��������������������������������� Norway rat 24. Mandibular toothrow < 6 mm������������������������������������Kiore – Mandibular toothrow > 6 mm��������������������������������Ship rat 25. Width of internal nares more than narrowest part of palatal bridge and exceeds length of molar row; no

Key to skulls

suture between supraoccipital and interparietal bones; supraorbital processes massive, triangular in shape����������������������������������������������������������������Brown hare – Width of internal nares less than narrowest part of palatal bridge and same as length of molar row; distinct suture between supraoccipital and interparietal bones; supraorbital processes narrow and slender�������������������������������������������������������������������Rabbit 26. Skull broad in shape, length < 14.3 mm�� Long-tailed bat – Skull narrow in shape, length > 17.3 mm����������������������� 27 27. Length of skull 17.3–19.1 mm�������� Lesser short-tailed bat – Length of skull 21.0–22.5 mm�����Greater short-tailed bat 28. Premolars 4/4, molars 2/3����������������������������������������������Dog – Premolars 2–3/2, molars 1/1������������������������������������������� Cat – Premolars 3/3, molars 1/2 [Mustelids]���������������������������� 29 29. Length of skull > 54 mm, mandible > 32 mm; rostrum parallel-sided�������������������������������������������������Ferret – Length of skull < 54 mm, mandible < 32 mm; rostrum not parallel-sided������������������������������������������������ 30 30. Length of skull > 42 mm, mandible > 22 mm; infraorbital foramina distinctly larger than diameter of canines�������������������������������������������������������������������������Stoat – Length of skull < 42 mm but not < 30 mm, mandible 500 mm, with elongate nose (distance from anterior tip of nasal bone to anterior tip of intermaxilla almost the same as that from posterior edge of nasal bone to posterior edge of occipital bone)��������������������������������������������������������������Moose – Skull length < 400 mm, with nose shorter than cranium (comparative distances not as above)�������������� 33 33. Lachrymal fossae in front of each orbit rather shallow; vomer divides nares into two separate chambers posteriorly; width of auditory bullae equal to length of ear canal�����������������������������������������������White-tailed deer – Lachrymal fossae deep; vomer and bullae not as above������������������������������������������������������������������������������������� 34 34. Upper canines usually absent���������������������������Fallow deer – Upper canines usually present������������ Cervus, Rusa, Axis Note: There is insufficient information available at the time of writing to complete this key down to the species of Cervus, Rusa and Axis. The males, at least for part of the year, can be distinguished by their antlers (Fig. 14.1).

533

Index to animal species Primary species accounts are listed under Family names. For names of authors, geographic places and plants, search the e-book. For subjects, search under the standardised headings listed on p. xxxvii. alpaca (Vicugna pacos, Family Camelidae) viii, xix, xxii, xxix axis deer, see Cervidae banded rail (Rallus philippensis) 326, 361 batfly (Mystacinobia zelandica) 121 bats Pteropodidae xvii, 95–6 Yangochiroptera xvi, 95–130 bellbird (Anthornis melanura) 204, 308, 353 Bennett’s wallaby, see Macropodidae black-striped wallaby, see Macropodidae black swan (Cygnus atratus) 315 blackbird (Turdus merula) 319, 348 Bovidae (Ch 13, horned ungulates) xxii, xxiv, 393–445, Plates 9–11 alpine chamois (Rupicapra rupicapra rupicapra) xix, xxii, xxv, xix, xxix, xxx, xxxiii, 151, 393, 394, 397, 398–405, 406, 410, 415, 423, 430, 528, 531, 532 aurochs (Bos primigenius) 393, 395 black wildebeest, gnu (Connochaetes gnou) xix, 393 blue sheep, bharal (Pseudois nayaur) xix, xxii, 393 cattle (Bos taurus) domestic viii, xxv, xxvii, xxix, xxxi, xxxvi, 58, 59, 61, 63, 64, 89, 304, 319, 324, 325, 326, 351, 359, 395, 418, 421, 428, 436, 458, 458, 462, 479, 498, 503, 532 feral xxiv, 393–7, 532 Himalayan tahr (Hemitragus jemlahicus) xix, xxii, xxv, xxix, xxx, xxxiii, 393, 394, 398, 401, 402, 403, 404, 405–16, 423, 430, 528, 532 goat (Capra hircus) domestic viii, xxiv, xxix, xxx, 393, 398, 417, 418, 419, 424, 431–2, 433, 458 feral xix, xxii, xxiv, xxv, xxvii, xxix, xxx, xxxi, xxxiii, xxxvi, 19, 354, 380, 387, 394, 397, 398, 402, 405, 417–32, 433, 434, 436, 458, 461, 462, 477, 497, 528, 530, 532 pig, see Suidae sheep (Ovis aries) domestic viii, xxix, 8, 11, 12, 13, 82, 89, 133, 134, 141, 142, 282, 319, 320, 325, 351, 359, 380, 386, 393, 402, 404, 414, 417, 418, 427, 428, 432–4, 436–47, 458, 491, 503, 508 feral xix, xxiv, xxvii, xxxi, xxxvi, 394, 423, 424, 432–7, 528, 532 bovine TB, see parasites and diseases brown creeper (Finschia novaeseelandiae) 307, 361 brushtailed rock wallaby, see Macropodidae

California quail (Callipepla californica) 357 Canidae (Ch 8, dogs) 279–84, Plate 7 dingo (Canis familiaris) 61, 279, 281, 419 European (Canis familiaris) xviii, xxxvi, 6, 12, 13, 14, 17, 20, 90, 143, 193, 199, 206, 249, 263, 266, 280–1, 283, 287, 306, 307, 309, 325, 327, 362, 386, 388, 423, 427, 431, 462, 485, 488, 491, 502 kurī (Canis familiaris) vii, xviii, xix, xxi, xxii, xxix, xxxvi, 174, 279–83, 306, 325, 530 cat, see Felidae cattle, see Bovidae Cervidae (Ch 14, deer) xxii, xxiv, xxv, xxix, xxx, 151, 192, 324, 326, 380, 387, 416, 418, 424, 429, 430, 432, 433, 447–527, Plates 12–14 chital (Axis axis) vii, xix, xxii, 447, 448, 450, 492–3 common fallow (Dama dama) xix, xxx, xxxi, 447–50, 451, 459, 462, 475, 479, 493–503, 507 huemul, South Andean (Hippocamelus bisulcus) 504 moose (Alces alces andersoni) xix, xxi, xxii, xxiv, 447–8, 450, 462, 467, 510–14 mule, black-tailed (Odocoileus hemionus) xix, xxii, 498, 504 Père David’s (Elaphurus davidianus) viii, 449 rusa (Rusa timorensis) xix, xxii, xxxii, xxxiii, 447–50, 451, 462, 475, 481, 482, 484, 486–92 sambar (Rusa unicolor) xix, xxii, xxxii, xxxiii, 447–50, 451, 475, 480–6, 487, 488 sika (Cervus nippon) xix, xxii, xxxiii, 447–50, 451, 453, 459, 462, 463, 474–80 wapiti (Cervus canadensis) xix, xxii xxx, xxxii, xxxiii, 447–50, 451, 453, 462, 467–74, 475, 513 western red (Cervus elaphus) xix, xxii, xxv, xxvii, xxix, xxx, xxxi, xxxii, xxxiii, 7, 380, 398, 399, 402, 404, 405, 415, 447–74, 477, 478, 479, 480, 482, 484, 486, 487, 488, 490, 491, 492, 493, 495, 501, 502, 503, 504, 508, 509, 510, 511–14 white-tailed (Odocoileus virginianus borealis) xix, xxii, 447–50, 451, 462, 504–10 Cetacea (whales and dolphins) viii, 359 chaffinch (Fringilla coelebs) 348 chamois, see Bovidae chinchilla (Chinchilla laniger, Family Chinchillidae) viii, 161 chipmunk, grey (Tamias striatus, Family Sciuridae) xviii, xxiii, 161 Chiroptera, see Yangochiroptera chital, see Cervidae coypu (Myocastor coypus, Family Echimyidae) xxiv crabeater seal, see Phocidae crayfish, koura (Paranephrops) 293, 351

Index to animal species

dama wallaby, see Macropodidae deer, see Cervidae dog, see Canidae dotterels (Charadrius) banded (Charadrius bicinctus) 83, 89, 142, 310, 326, 357, 361, 362 New Zealand (Charadrius obscurus) 86, 90, 191, 192, 308, 326, 361, 362 ducks, Anatidae 282 blue (Hymenolaimus malacorhynchos) 307 eagles, extinct xix elephant seal, see Phocidae elk 467, 510, see also moose; wapiti Equidae (Ch 11, horses) 371–7, Plate 9 feral domestic (Equus caballus) xviii, xxxi, xxxvi, 371–7, 529, 531, 532 Przewalski’s horse, takhi (Equus przewalskii) 371, 373 tarpan (Equus ferus) 373 zebra, southern plains (Equus quagga) 371 Erinaceidae (Ch 3, hedgehogs) 79–93, Plate 2 European (Erinaceus europaeus occidentalis) xviii, xxi, xxi, xxxvii, xxv, xxxiii, 79–90, 145, 306, 310, 320, 328, 348, 350 falcon, New Zealand (Falco novaeseelandiae) 120, 124, 219, 304 fallow deer, see Cervidae fantail (Rhipidura fuliginosa) 62, 205, 353, 357 Felidae (Ch 10, cats) 343–70, Plate 7 domestic (Felis catus) 106, 120, 194, 203, 249, 343, 363 feral (Felis catus) xviii, xxi, xxiv, xxxvii, 47, 87, 106, 136, 139–42, 145, 150, 178, 179, 191, 200, 202, 203, 217, 297, 302, 304, 306, 314, 315, 320, 323, 328–9, 343–64 wild (Felis silvestris) 343 fernbird (Bowdleria punctata) 205, 361 ferret, see Mustelidae fish 187, 220, 243, 244, 247, 253, 255, 258, 262, 264, 266, 267, 282, 294 fox flying, see Pteropodidae red (Vulpes vulpes) xxiii, 19, 47, 52, 61, 306 frogs (Amphibia) 111, 180, 191, 283, 314, 318, 319, 325, 351, 357, 382 fur seals, see Otariidae geckos, Family Gekkonidae 82, 90, 111, 311, 319, 348, 351, 359 common (Hoplodactylus maculatus) 181, 220 Duvaucel’s (Hoplodactylus duvaucelii) 181 goat, see Bovidae goldfinch (Carduelis carduelis) 348 greenfinch (Carduelis chloris) 348 grey warbler (Gerygone igata) 353, 357 guinea pig (Cavia porcellus, Family Caviidae) viii, xviii, 161 gull, black-backed (Larus dominicanus) 145

hare, see Leporidae harrier, kahu (Circus approximans) 62, 87, 141, 145, 150, 179, 191, 219, 304, 314 hawks, extinct xix hedgehog, see Erinaceidae Himalayan tahr, see Bovidae horse, see Equidae invertebrates xvi, 51, 81–3, 90, 102–3, 111, 114–16, 120, 123–4, 143, 145, 175, 177, 180–1, 187–8, 192, 198, 202, 203, 204, 205, 206, 210, 211–12, 216, 220, 243, 293, 294, 302, 305, 312, 314, 318, 319, 320, 325, 348, 351–2, 353, 355, 357, 359, 382 see also wētā, snails kākā (Nestor meridionalis septentrionalis) xxvi, 62, 191, 221, 295, 307, 308 kākāpō (Strigops habroptilus) 182, 205, 282, 306, 353, 361 kakariki (parakeets) 62, 282, 307, 353 Kermadec (Cyanoramphus novaezelandiae cyanurus) 361 red-crowned (Cyanoramphus novaezealandiae) 205 yellow-crowned (Cyanoramphus auriceps) 205, 221, 308, 361 kangaroo xxiii, 1 kekeno, see Otariidae, eared seals kererū/kukupa (Hemiphaga novaeseelandiae) 62, 353, 357 killer whale (Orca sp.) 259, 263, 266, 267 kingfisher (Halcyon sancta) 179, 219, 353 kiore (Polynesian rat), see Muridae kiwi (Apteryx) xxii, xxvi, 62, 90, 144, 202, 203, 206, 282, 295, 307, 325, 361, 387, 388, 431 kōkākō, Callaeidae North I. (Callaeas cinerea wilsoni) xxvi, 62, 205, 206, 307, 308 South I. (Callaeas cinerea cinerea) 205, 306, 307 kurī, see Canidae leopard seal, see Phocidae Leporidae (Ch 5, lagomorphs) xxi, xxiii, xxx, 131–59, 293, 294–5, Plate 7 brown hare (Lepus europaeus occidentalis) xviii, xxxiii, xxxvii, 131, 145, 146–52, 350, 405, 415, 423 cottontail rabbit (Sylvilagus sp.) 131 desert hare (Lepus capensis) 148 domesticated rabbit (Oryctolagus cuniculus) xxix, xxxvi, 132–3, 136, 143 European wild rabbit (Oryctolagus cuniculus cuniculus) xviii, xxiv, xxv, xxxvii, xxxiii, 19, 131–46, 149, 192, 293, 295, 309, 311, 312, 316, 318, 319, 320, 322, 324, 325, 347, 348, 351–2, 353, 354, 357, 360, 382, 393, 423 mountain hare (Lepus timidus) 146, 151 lizards xiv, xx, xxiv, 82, 90, 177, 181, 187, 199, 205, 211–12, 220, 283, 293, 294, 383, 311–12, 314, 318, 319, 320, 328, 348, 351–2, 353, 355, 357, 359, 361, 382 see also skinks, Family Scincidae; geckos, Family Gekkonidae llama (Lama glama, Family Camelidae) viii, xix, xxix long-nosed potoroo (Potorous tridactylus, Family Potoroidae) xvii, 1

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Macropodidae (Ch 1, wallabies) xxi, xxx, 1–26, Plate 1 Bennett’s (Macropus rufogriseus rufogriseus) xvii, xxxiii, 2, 8–14 black-striped (Macropus dorsalis) vii, xvii, 17–18 brushtailed rock (Petrogale penicillata) xvii, 2, 18–21 dama, tammar, silver-grey (Macropus eugenii) xvii, xxi, xxxi, 2–8 parma (Macropus parma) xvii, xxxi, 2, 14–17 roan wallaby, wallaroo (Macropus robustus) xvii, 1 swamp (Wallabia bicolor) xvii, 2, 21–3 marsupial cat (Dasyurus sp, Family Dasyuridae) xviii, 1 moa xix, xx, xxix, 281, 282, 283 mohua, yellowhead (Mohoua ochrocephala) xxvi, 205, 221, 295, 307, 308 mole (Talpa europaea) xxiv mongooses (Family Herpestididae) xviii, viii, xxiii, 343 moose, see Cervidae morepork, see owls mouse, mice see Muridae Muridae (Ch 6, rodents) xxxvii, xxi, xxiii, xxiv, 320, 348, 351–4, 382, Plate 4 European species 210, 220, 295, 306, 312, 313, 314, 315 house mouse (Mus musculus) xx, xxvii, xxxii, xxxiii, 82, 162, 178, 190, 199, 202, 203, 207–21, 293, 294, 295, 300, 305, 306, 311, 314, 319, 351–2, 354, 360 kiore, Polynesian rat (Rattus exulans) xviii, xix, xxi, xxiv, xxix, xxxiii, 120, 124, 161, 162–82, 183, 186, 190, 192, 197, 203, 207, 217, 295, 353 Norway rat (Rattus norvegicus) xviii, xx, xxii, xxiv, 161, 162, 176, 177, 178–9, 183–93, 194, 198, 201, 204, 210, 217, 249, 295, 306, 353, 361, 363 ship, black, roof rat (Rattus rattus) xviii, xxii, xxvii, xxxiii, 63, 106, 120, 124, 162, 176, 178–9, 183, 186, 187, 190–1, 184, 193–207, 216, 217, 219, 293, 294, 295, 301, 306, 318, 351–2, 353, 357, 360 muskrat (Ondatra zibethicus, Family Cricetidae) xxiv Mustelidae (Ch 9, weasels and ferrets) xxi, xxv, xxvi, xxxviii, 285–341, Plate 8 American mink (Neovison vison) xxiv, 286, 306 common weasel (Mustela nivalis vulgaris) xviii, xxii, xxvii, xxxvi, 150, 203, 219, 286, 302, 306, 309–16 feral ferret (Mustela furo) xviii, xxix, xxxvi, xxx, xxxiii, 59, 87, 139–42, 145, 150, 191, 203, 219, 286, 296, 297, 302, 304, 307, 308, 309, 311, 314, 315, 316–29 polecat (Mustela putorous putorius) 285, 306, 316, 318 stoat, ermine (Mustela erminea) xvi, xviii, xxxvi, xxvii, xxxiii, 63, 97, 106, 120, 139, 141, 145, 150, 178, 179, 186, 187, 191, 194, 200, 202, 203, 205, 216, 217, 219, 221, 285–309, 311, 313, 314, 315, 325, 328–9, 350, 361 muttonbird (Puffinus griseus), see shearwaters Norway rat, see Muridae octopus 243, 258 Enteroctopus zelandicus 253 Octopus maorum 247, 253 opossum, American (Didelphis sp) 43

Otariidae (Ch 7, eared seals) xxii, xxxvii, 241–55, Plate 5 Antarctic fur seal (Arctocephalus gazelle) 241, 249–50, 264 Australian sea lion (Neophoca cinerea) 250 New Zealand fur seal, kekeno (Arctocephalus forsteri) xvii, xxii, xxxvii, 246, 250–1 New Zealand sea lion (Phocarctos hookeri) xvii, 242, 246, 248, 250–5 southern sea lion (Otaria flavescens) 250 subantarctic fur seal (Arctocephalus tropicalis) xvii, 241, 242, 246, 249–50 see also Phocidae otter, ‘New Zealand’ viii, 285 owlet-nightjar, New Zealand (Aegotheles novaezealandiae) 285 owls laughing (Sceloglaux albifacies) 106, 120, 124, 176, 179, 306 little (Athene noctua) 106, 150, 219 morepork (Ninox novaeseelandiae) 106, 120, 124, 179, 203, 219 oyster-catchers pied (Haematopus finschi) 89 variable (Haematopus unicolor) 326 parakeets, see kakariki parasites and diseases xx, xxxiii bovine TB 58, 63, 87, 304, 314, 324, 326, 359, 386, 395, 397, 462–3, 472, 479, 485, 491, 502 of bats 107, 120–1 of bovids 397, 403–4, 414, 427–9, 435–6 of cats 359–60 of deer 449, 462, 467, 472, 479, 485, 491, 501,502, 508 of dogs 283 of hedgehogs 87–9 of horses 375 of leporids 141, 143–4, 150, 151 of murids 176, 179–80, 191, 203–4, 213, 219–20 of mustelids 304, 314, 325, 327 of pigs 386, 427 of pinnipeds 248, 254, 259, 266, 268 of possums 57 of wallabies 6, 13, 17, 21 parma wallaby, see Macropodidae pekapeka, see Yangochiroptera penguins, Spheniscidae xix, 264 Adèlie (Pygoscelis adeliae) 264 chinstrap (Pygoscelis antarctica) 262 Fiordland crested (Eudyptes pachyrhynchus) 295 gentoo (Pygoscelis papua) 262 little blue (Eudyptula minor) 244, 319, 325, 353 rockhopper (Eudyptes chrysocome) 244 white-flippered (Eudyptula minor albosignata) 325 yellow-eyed (Megadyptes antipodes) 308, 319, 325, 326, 327, 328, 348, 361 petrels, Procellariidae 295, 436 black (Procellaria parkinsoni) 361 black-winged (Pterodroma nigripennis) 361 broad-billed prions (Pachyptila vittata) 361 Cook’s (Pterodroma cookii) 181, 361

Index to animal species

diving (Pelecanoides spp.) 244, 353, 361 grey-faced (Pterodroma macroptera gouldi) 188, 192, 361 Kermadec (Pterodroma neglecta) 361 Pycroft’s (Pterodroma pycrofti) 181 Phalangeridae (Ch 2, possums), Plate 2 common brushtail (Trichosurus vulpecula) xvii, xxii, xxiii, xxiv, xxv, xxvi, xxx, xxxiii, 1, 7, 21, 43–65, 106, 120, 202, 205, 293, 294, 304, 308, 309, 318, 320, 324, 348, 350, 354, 357, 362, 385, 386, 405, 415, 418, 429, 462, 509 cuscus (Phalanger sp.) 43 scalytailed (Wyulda sp.) 43 Phocidae (Ch 7, true seals) 255–68, Plate 6 crabeater seal (Lobodon carcinophagus) xvii, 242, 246, 261, 265–6 leopard seal (Hydrurga leptonyx) xvii, 242, 246, 248, 259, 261, 263–7 Ross seal (Ommatophoca rossi) xvii, 242, 246, 261, 266–8 southern elephant seal (Mirounga leonina) xvii, 242, 246, 255–61 Weddell seal (Leptonychotes weddellii) xvii, 242, 246, 260–3, 265 see also Otariidae Pig, see Suidae pigeon feral (Columba livia) 107 New Zealand (Hemiphaga novaeseelandiae), see kererū pinnipeds xix, xxi, xxviii, xxix, 241 see also Otariidae, Phocidae pipit (Anthus novaezeelandiae) 191 plover, New Zealand (Thinornis novaeseelandiae) 192 Polynesian rat (kiore) see Muridae possum, see Phalangeridae Pteropodidae, flying foxes dog-faced fruit bat (Cynopterus brachyotis) 96 little red (Pteropus scapulatus) viii, xvi, xvii, 95, Plate 3 pukeko (Porphyrio porphyrio) 143, 308 rabbit, see Leporidae raccoon (Procyon lotor, Family Procyonidae) xviii, xxiii, 241 rats, see Muridae red deer, see Cervidae redpoll (Carduelis flammea) 353 rifleman (Acanthisitta chloris) 111 ringtail possum (Pseudocheirus peregrinus, Family Pseudocheiridae) 1, xviii roan wallaby, see Macropodidae robins, Petroicidae North I. (Petroica australis longipes) 205, 206, 327 South I. (Petroica australis australis) 204, 361 Stewart I. (Petroica australis rakiura) 205 rosella (Platycercus eximius) 357 Ross seal, see Phocidae rusa deer, see Cervidae saddlebacks, Notiomystidae 62, 206 North I. (Philesturnus carunculatus rufusater) 182, 191, 205, 360

South I. (Philesturnus carunculatus carunculatus) 192, 205, 306, 309 sambar deer, see Cervidae seals, see Phocidae sea-lions, see Otariidae sharks 248, 259 shearwaters, Procellariidae flesh-footed (Puffinus carneipes) 191 Hutton’s (Puffinus huttoni) 297, 301, 308 little (Puffinus assimilis haurakiensis) 181 sooty (Puffinus griseus) 62, 123–4, 191, 319, 326 wedge-tailed (Puffinus pacificus) 361 sheep, see Bovidae shining cuckoo (Chrysococcyx lucidus) 353 ship rat, see Muridae sika deer, see Cervidae silvereye (Zosterops lateralis) 353, 357 skinks, Family Scincidae 82, 111, 143, 177, 181, 311, 312, 319, 325, 348, 351, 353, 355, 359, 361 copper (Oligosoma aeneum) 312 Fiordland (Oligosoma acrinasum) 192 grand (Oligosoma grande) 327, 361 McCann’s (Oligosoma maccanni) 90 McGregor’s (Cyclodina macgregori) 220 Otago (Oligosoma otagense) 327, 361 shore (Oligosoma smithi) 220 Suter’s (Oligosoma suteri) 82, 181 Whitaker’s (Oligosoma whitakeri) 315 skylark (Alauda arvensis arvensis) 319 snails aquatic (Lymnaea truncatula) 462 land (Powelliphanta, Placosytylus) 50, 62, 176, 205, 325, 382, 387, 388, 436 snakes xxiv, 61 snipes, Scolopacidae Auckland I. (Coenocorypha aucklandica aucklandica) 191 Campbell I. (Coenocorypha aucklandica perseverance) 191 Little Barrier (Coenocorypha aucklandica barrierensis) 360 Stewart I. (Coenocorypha aucklandica iredalei) 205, 361 southern brown bandicoot (Isoodon obesulus, Family Paramelidae) xviii, 1 southern crested grebe (Podiceps cristatus australis) 326 southern royal albatross (Diomedea epomophora) 436 sparrows hedge (Prunella modularis) 348, 353 house (Passer domesticus) 107, 319, 348 spotless crake (Porzana tabuensis) 326 squid 243, 250, 254, 255, 258 arrow (Nototodarus sloanii) 247, 253 squirrels, Family Sciuridae 198 American grey (Sciurus carolinensis) xxiv ‘brown Californian’ xviii, xxiii, 161 starling (Sturnus vulgaris) 107 stilts, Recurvirostridae black (Himantopus novaezelandiae) 89, 308, 326, 357, 361, 362 pied (Himantopus himantopus) 308, 357

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stitchbird (Notiomystis cincta) 204 stoat, see Mustelidae subantarctic skua (Catharacta antarctica) 435 Suidae (Ch 12, pigs) xxxvi, 379–91, Plate 9 domestic (Sus scrofa) xxix, 379–88, 382, 385 Eurasian wild boar (Sus scrofa) 379, 381, 386 feral (Sus scrofa) xix, xxvii, xxx, xxxvi, 50, 87, 282, 308, 324, 354, 361, 379–91, 404, 416, 427, 430, 432, 433, 436, 437, 430, 432, 436 , 491, 532 kunekune (Sus scrofa) 380 swamp wallaby, see Macropodidae tahr, Himalayan, see Bovidae takahē (Porphyrio mantelli hochstetteri) 306, 307, 308, 464–5, 472 tammar wallaby, see Macropodidae teals, Anatididae brown (Anas chlorotis) 327 flightless (Anas nesiotis) 191 terns, Laridae black-fronted (Sterna albostriata) 83, 89–90, 192, 308, 326, 361 Caspian (Hydroprogne caspia) 326 fairy (Sterna nereis) 326 sooty (Sterna fuscata) 361 thrushes New Zealand (Turnagra capensis) 205, 306 song (Turdus philomelos) 319, 348 tits or tomtits, Petroicidae 353 North I. (Petroica macrocephala toitoi) 205 tuatara (Sphenodon punctatus) 111, 181, 206 tui (Prosthemadera novaeseelandiae) 62, 282, 353, 357 wapiti, see Cervidae weasel, see Mustelidae Weddell seal, see Phocidae

weka (Gallirallus australis) 87, 141, 179, 219, 282, 304, 325, 326 buff (Gallirallus australis hectori) 326 welcome swallow (Hirundo neoxena) 353 wētā xxii, 111, 177, 181, 192, 194, 198, 204, 205, 210, 220, 293, 311, 312, 314, 319, 351, 353, 355 Cook Strait giant (Deinacrida rugosa) 206 Hemiandrus sp 83 Hemideina thoracica 116 Mahoenui giant (Deinacrida mahoenui) 205 whitehead (Mohoua albicilla) 327 white-tailed deer, see Cervidae wrens, Acanthisittidae rock (Xenicus gilviventris) 220, 286, 307 South I. bush (Xenicus longipes longipes) 306 Stead’s bush (Xenicus longipes variabilis) 205 Stephens I. (Xenicus lyalli) 360 wrybill (Anachynchus frontalis) 89, 308, 326, 362 Yangochiroptera (Ch 4, microbats) 95–130, Plate 3 accidental imports xvi Japanese pipistrelle (Pipistrellus javanicus abramus) 95 lesser long-eared (Nyctophilus geoffroyi) 95 little forest (Vespadelus vulturnus) 95 wrinkle-lipped free-tailed (Tadarida plicata) 95 common vampire bat Desmodus rotundus 110 extinct xvi, 108 New Zealand endemic bats xvi, xxi, xxii, xxxvii, 62, 95–130, 314 New Zealand greater short-tailed (Mystacina robusta) xvi, xxvii, xii, xxvii, 97, 108, 109, 110, 115, 120, 122–4, 205 New Zealand lesser short-tailed (Mystacina tuberculata) xvi, xvii, 97, 108–122, 144, 205, 361 New Zealand long-tailed (Chalinolobus tuberculatus) xvi, xvii, 96–107, 109, 361