Albatrosses Petrels & Shearwaters of the World

Field GUide to the

Albatrosses, petrels and shearwaters of the World

Derek Onley and Paul Scofield

Christopher helm london

Like so many ocean sailors, I have a huge respect for these incredible birds, which circle Antarctica over the most inhospitable oceans in the world. I hope that through the images and information in this book those of you who have felt the sheer presence of these birds can re-live it, and those who haven’t can begin to experience it. Dame Ellen MacArthur

Published 2007 by Christopher Helm, an imprint of A&C Black Publishers Ltd, 36 Soho Square, London W1D 3QY Reprinted 2008 Electronic edition 2010 Copyright © 2007 artwork by Derek Onley Copyright © 2007 text by Paul Scofield and Derek Onley The right of Derek Onley and Paul Scofield to be identified as the authors of this work has been asserted by them in accordance with the Copyright, Design and Patents Act 1988. ISBN (print) 978-0-7136-4332-9 ISBN (e-pub) 978-1-4081-0877-2 ISBN (e-pdf) 978-1-4081-3579-2 A CIP catalogue record for this book is available from the British Library All rights reserved. No part of this publication may be reproduced or used in any form or by any means – photographic, electronic or mechanical, including photocopying, recording, taping or information storage or retrieval systems – without permission of the publishers. Commissioning Editor: Nigel Redman Project Editor: Jim Martin Designer: Julie Dando, Fluke Art, Cornwall

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CONTENTS List of species and subspecies

4

Preface

11

Acknowledgements

11

Taxonomy and the species debate

12

The four families: characteristics and taxonomic relationships

14

Identification

19

Conservation

25

How to use this book

29

Seabird topography

31

Colour plates

32

Species accounts

122

Albatrosses

122

Fulmarine petrels

143

Prions

151

Bulweria and Psuedobulwaria petrels

157

Gadfly petrels

161

Procellaria petrels

187

Shearwaters

191

Diving-petrels

215

Storm-petrels

218

References

237

Index

238

LIST OF SPECIES AND SUBSPECIES the species within the families are generally listed in the same sequence as in dickinson (2003). however, a number of taxa treated as subspecies there have been raised to species level, bringing the total number of procellariiform species illustrated and discussed in this book to 137. The figure on the right shows the relevant plate in each case. For polytypic species, races are listed in small type. Abbreviated ranges are given for all taxa. subspecies are generally listed in order of publication. the order used here within the pterodromas and shearwaters is artificial and is designed simply to help identification.

Family DIOMEDEIDAE (albatrosses) a) Wandering albatrosses

plate no.

Diomedea exulans Snowy Albatross (Wandering Albatross)

1, 2

Diomedea dabbenena Tristan Albatross

1, 2

Diomedea antipodensis New Zealand Albatross

1, 2

Circumpolar s hemisphere, breeding on higher-latitude islands of southern ocean except new Zealand. tristan da Cunha and Gough i., ranging at sea through south Atlantic.

D. a. antipodensis (Antipodean Albatross) Circumpolar s hemisphere, breeding on Antipodes i. and in small numbers on Campbell i. and Chatham is. D. a. gibsoni (Gibson’s Albatross) Circumpolar s hemisphere, breeding on Auckland is.

Diomedea amsterdamensis Amsterdam Island Albatross

Amsterdam i. (indian ocean). ranges at sea across southern indian ocean.

1

b) Royal albatrosses Diomedea sanfordi Northern Royal Albatross

1, 3

Diomedea epomophora Southern Royal Albatross

1, 3

Circumpolar s hemisphere; breeds mainly on Chatham is. Circumpolar s hemisphere; breeds mainly on Campbell is., with smaller population on enderby i., Auckland i.

c) North Pacific albatrosses Phoebastria irrorata Waved Albatross

5

Phoebastria albatrus Short-tailed Albatross

4

Phoebastria nigripes Black-footed Albatross

4

Phoebastria immutabilis Laysan Albatross

7

Tropical E Pacific; breeding confined to the Galápagos Is.; range to adjacent seas as far as S America. NW Pacific. Breeds mainly on Tori-shima (Japan), ranges S and E. Central and western N Pacific. Most breed on NW Hawaiian Is. with some in S Japan. Ranges SE to equator. Central N Pacific and off Baja California. Ranges from Japanese seas N to Bering Sea, E to Pacific coast of n America.

d) Mollymawks Thalassarche melanophris Black-browed Albatross

7, 9

Thalassarche impavida Campbell Albatross

7, 9

Circumpolar s hemisphere, breeding on higher-latitude islands of southern ocean. Circumpolar s hemisphere, breeding only on Campbell i.

Thalassarche cauta Shy Albatross

6

Thalassarche eremita Chatham Islands Albatross

6

Thalassarche salvini Salvin’s Albatross

6

T. c. cauta Circumpolar s hemisphere, breeding on islands off tasmania. T. c. steadi (White-capped Albatross) Circumpolar s hemisphere, breeding on islands off new Zealand. S Pacific. The Pyramid in Chatham Is. provides sole breeding ground. Migrates to Chilean and Peruvian waters in winter. S Pacific. Breeds on Bounty and Snares Is., migrates to Chilean and Peruvian waters in winter.

Thalassarche chrysostoma Grey-headed Albatross

Circumpolar s hemisphere, breeding on higher-latitude islands of southern ocean.



8, 9

Thalassarche chlororhynchos Atlantic Yellow-nosed Albatross

8, 9

Thalassarche carteri Indian Yellow-nosed Albatross

8, 9

Thalassarche bulleri Buller’s Albatross

8, 9

Circumpolar s hemisphere, tristan da Cunha group and Gough i., ranging at sea through s Atlantic. Circumpolar s hemisphere, breeding on lower-latitude islands of s indian ocean.

T. b. bulleri (southern Buller’s Albatross) Circumpolar s hemisphere, breeds on the snares and solander around stewart is. T. b. ssp. nov. (northern Buller’s Albatross) Breeds on sisters and Forty-Fours in Chatham is. and on three Kings islands north of new Zealand. subspecies yet to be formally named.

e) Sooty albatrosses Phoebetria fusca Sooty Albatross

10

Phoebetria palpebrata Light-mantled (sooty) Albatross

10

Circumpolar s hemisphere, warmer subantarctic waters of s Atlantic and indian oceans. Circumpolar s hemisphere. ranges at sea in colder Antarctic waters as far south as ice edge.

Family PROCELLARIIDAE (petrels) a) Fulmarine petrels Macronectes giganteus Southern Giant Petrel

11

Macronectes halli Northern Giant Petrel

11

Fulmarus glacialis Northern Fulmar

12

Fulmarus glacialoides Southern Fulmar

12

Thalassoica antarctica Antarctic Petrel

13

Daption capense Cape Petrel

13

Pagodroma nivea Lesser Snow Petrel

13

Pagodroma confusa Greater Snow Petrel

13

Lugensa brevirostris Kerguelen Petrel

14

Halobaena caerulea Blue Petrel

27

Circumpolar southern ocean; restricted to Antarctic waters in winter. Circumpolar southern ocean; ranges to subtropics in winter. F. g. auduboni low Arctic and temperate n Atlantic. F. g. glacialis high-arctic n Atlantic. F. g. rodgersii Colder waters of N Pacific and Bering Sea. Circumpolar southern ocean; cold-water species of southern ocean and Antarctic. Circumpolar southern ocean; cold-water species of southern ocean and Antarctic. D. c. capense Circumpolar southern ocean; occurs in subtropics in winter D. c. australe new Zealand waters Antarctic waters, rarely far from ice.

eastern Antarctic waters, rarely far from ice.

Circumpolar southern ocean; a cold water species. Circumpolar southern ocean; a cold water species.

b) Prions Pachyptila vittata Broad-billed Prion

26

Pachyptila salvini Salvin’s Prion

26

Pachyptila macgillivrayi MacGillivray’s Prion

26

Pachyptila desolata Antarctic Prion

26

new Zealand and se Atlantic, in warmer subantarctic waters just north of subtropical convergence. Breeds SW Indian Ocean, occurs throughout cooler circumpolar waters except SE Pacific in winter. endemic to st paul is. range at sea unknown.

Circumpolar southern Ocean, in colder waters but rarely reported in central S Pacific.

Pachyptila belcheri Slender-billed Prion

Circumpolar southern ocean, dispersive in colder waters.

26 

Pachyptila turtur Fairy Prion

27

Pachyptila crassirostris Fulmar Prion

27

P. t. turtur Circumpolar species of warmer subantarctic and subtropical waters. P. t. subantarctica Breeds on Antipodes, snares and macquarie is. P. c. crassirostris Chatham is, the snares and Bounty is. P. c. flemingi heard and Auckland is.

c) Bulweria and Pseudobulweria petrels Bulweria bulwerii Bulwer’s Petrel

15

Bulweria fallax Jouanin’s Petrel

15

Pseudobulweria aterrima Mascarene Petrel

15

Pseudobulweria becki Beck’s Petrel

17

Pseudobulweria rostrata Tahiti Petrel

17

Pseudobulweria macgillivrayi Fiji Petrel (macGillivray’s petrel)

17

Tropical waters of N Pacific and N Atlantic. nW indian ocean, breeding on socotra is. and islands off southern oman. réunion i. in W indian ocean.

seas off new ireland and solomon islands. P. r. rostrata marquesa is. and society is. P. r. trouessarti new Caledonia. Gau i., Fiji and adjacent waters.

d) Gadfly petrels i) Cookilaria petrels Pterodroma axillaris Chatham Islands Petrel

23

Pterodroma nigripennis Black-winged Petrel

23

Pterodroma inexpectata Mottled Petrel

23

Pterodroma hypoleuca Bonin Petrel

23

Pterodroma leucoptera Gould’s Petrel

24

Pterodroma cookii Cook’s Petrel

22

Pterodroma pycrofti Pycroft’s Petrel

22

Pterodroma brevipes Collared Petrel

24

Pterodroma defilippiana De Filippi’s Petrel (mas a tierra petrel)

22

Pterodroma longirostris Stejneger’s Petrel

22

SW Pacific, breeding only on Chatham Is. Tropical and subtropical S Pacific.

Pacific Ocean; breeds in S New Zealand, foraging south to ice edge; migrates to NW Pacific. Subtropical west and central N Pacific.

P. l. leucoptera Cabbage Tree I., Australia; SW and C Pacific. P. l. caledonica (New Caledonia Petrel) New Caledonia; E Pacific. Hauraki Gulf and Stewart Is., New Zealand; migrates to NE and central E Pacific. N New Zealand islands; migrates to NE and central E Pacific. Islands of SW Pacific. Islands of E Pacific.

Alejandro Selkirk I. (Mas Afuera), Juan Fernández Is. Range at sea in Pacific poorly known.

ii) The large, subtropical Pterodroma petrels Pterodroma alba Phoenix Petrel

Tropical and subtropical central Pacific.

Pterodroma heraldica Herald Petrel Tropical and subtropical Pacific.

Pterodroma arminjoniana Trindade Petrel tropical W Atlantic and W indian oceans.



17 16, 17, 25 20, 25

Pterodroma atrata Henderson Petrel

16

Henderson Island, central E Pacific.

Pterodroma neglecta Kermadec Petrel

P. n. neglecta SW and central Pacific. P. n. juana Juan Fernández Is. and Desventuradas.

16, 20, 25

Pterodroma ultima Murphy’s Petrel

16

Pterodroma solandri Providence Petrel

16

Tropical Pacific.

lord howe and phillip i. (norfolk Is); migrates to N Pacific.

iii) Large black-and-white Pterodroma petrels Pterodroma cervicalis White-necked Petrel

18

Pterodroma occulta Vanuatu Petrel

18

Pterodroma externa Juan Fernandez Petrel

18

Pterodroma baraui Barau’s Petrel

20

Pterodroma sandwichensis Hawaiian Petrel

18

Pterodroma phaeopygia Galápagos Petrel

18

Pterodroma cahow Cahow (Bermuda petrel)

21

Pterodroma hasitata Black-capped Petrel

21

Pterodroma caribbaea Jamaican Petrel

21

SW Pacific Ocean. Breeds on Kermadecs and Phillip Island, Norfolk Is. SW Pacific. N Vanuatu.

Alejandro Selkirk I., Juan Fernández Is., dispersing over the tropical and subtropical waters of E Pacific. Central and sW indian ocean, breeding only on réunion i. Central N Pacific, breeds on higher Hawaiian Islands. Central E Pacific; breeds on higher Galápagos Islands. Breeds on Bermuda; moves n into the Atlantic.

n Caribbean and western n Atlantic. Breeds on higher C Caribbean islands; moves up Gulf stream as far as north Carolina. Jamaica. probably extinct.

iv) Pterodroma petrels with dark underwings Pterodroma macroptera Great-winged Petrel

14

Pterodroma gouldi Grey-faced Petrel

14

Pterodroma lessonii White-headed Petrel

19

Pterodroma magentae Magenta Petrel (taiko)

19

Circumpolar subantarctic and Antarctic waters except new Zealand. Warmer waters of new Zealand and tasman sea. Circumpolar in colder subantarctic waters. Chatham is. and surrounding seas.

Pterodroma mollis Soft-plumaged Petrel

P. m. mollis Colder waters of Atlantic and new Zealand. P. m. dubia Colder waters of indian ocean and tasmania.

14, 19, 21

Pterodroma feae Fea’s Petrel (Cape Verde Petrel)

21

Pterodroma madeira Zino’s Petrel (madeira petrel)

21

Pterodroma incerta Atlantic Petrel (schlegel’s petrel)

19

subtropical ne Atlantic. madeira is.

s Atlantic; breeds on tristan da Cunha is. and Gough i.

e) Procellaria petrels Procellaria aequinoctialis White-chinned Petrel

28

Procellaria conspicillata Spectacled Petrel

28

Circumpolar southern ocean; breeds in colder waters, moving north in winter. sW Atlantic, breeding only on inaccessible i. (tristan da Cunha is.).



Procellaria parkinsoni Parkinson’s Petrel (Black petrel)

29, 30

Little and Great Barrier Is., New Zealand; winters in E tropical Pacific.

Procellaria westlandica Westland Petrel

29

West coast of South Island, New Zealand; migrates E temperate Pacific.

Procellaria cinerea Grey Petrel

29, 32

Circumpolar in colder subantarctic waters.

f) Larger shearwaters Calonectris diomedea Cory’s Shearwater

33

Calonectris edwardsii Cape Verde Shearwater

33

Calonectris leucomelas Streaked Shearwater

33

C. d. diomedea (scopoli’s shearwater) mediterranean. C. d. borealis Subtropical W Atlantic Is. other than Cape Verde; migrant to S Atlantic and Indian Oceans. Cape Verde Is.

NW Pacific, migrating to central W Pacific, Indonesia and E tropical Indian Ocean.

Puffinus pacificus Wedge-tailed Shearwater Tropical Pacific and Indian Ocean.

15, 30, 32

Puffinus bulleri Buller’s Shearwater

Warmer waters of Pacific except SE Pacific. Breeds only on Poor Knights I. near New Zealand; migrates to N Pacific.

32

Puffinus carneipes Flesh-footed Shearwater

29, 30

Puffinus creatopus Pink-footed Shearwater

32

Puffinus gravis Great Shearwater

32

Subtropical Indian and SW Pacific Oceans; migrates to N Pacific and NW Indian Oceans. E Pacific; migrates to N Pacific.

Atlantic and indian oceans; breeds only on tristan da Cunha and Gough i. migrates north.

Puffinus griseus Sooty Shearwater

Circumpolar in warm and subantarctic waters; migrates north mainly into Pacific and Atlantic Oceans.

14, 31

Puffinus tenuirostris Short-tailed Shearwater

31

Puffinus nativitatis Christmas Island Shearwater (Kiritimati shearwater)

30

Circumpolar in colder waters; breeds only in Tasmania; migrates north into arctic Pacific and Bering Sea. Tropical and subtropical Pacific.

g) Manx-type shearwaters Puffinus puffinus Manx Shearwater

35

Puffinus yelkouan Yelkouan Shearwater

35

Puffinus mauretanicus Balearic Shearwater

35

Puffinus opisthomelas Black-vented Shearwater

34

Puffinus gavia Fluttering Shearwater

36

Puffinus huttoni Hutton’s Shearwater

36

Atlantic ocean; breeds in cooler n waters and winters in C and sW Atlantic. Breeds throughout mediterranean except Balearic is., mostly migrating to Black sea. Breeds on Balearic is., dispersing into W Atlantic. Pacific off Mexico, dispersing NW.

northern new Zealand and tasman sea.

Central e new Zealand; migrates to Australia.

h) Little/Audubon’s Shearwater complex Puffinus elegans Subantarctic Little Shearwater

36, 37

Puffinus assimilis Little Shearwater

36, 37

Colder waters of SW Pacific, and Gough I. and Tristan da Cunha Is. in Atlantic. P. a. assimilis sW Pacific. Lord Howe Island and Norfolk Island.



P. a. kermadecensis SW Pacific. Kermadec Island. P. a. haurakiensis SW Pacific. Islands off North Island, New Zealand. P. a. tunneyi se indian ocean. Amsterdam and st paul is. and W Australia.

Puffinus baroli Macaronesian Shearwater

35, 37

Puffinus lherminieri Audubon’s Shearwater

34–37

The Azores, Madeira, Canary Is., Desertas and Salvage Is. P. l. lherminieri Bahamas and West indies. P. l. loyemilleri Caribbean Islands to Venezuela P. l. boydi Central E Atlantic Ocean. Cape Verde Is.

Puffinus bannermani Bannerman’s Shearwater

37

Puffinus persicus Arabian Shearwater

37

Puffinus bailloni Tropical Shearwater

37

NW Pacific Ocean. Bonin Is.

P. p. persicus Arabian sea. P. p. temptator Comoros is., nW indian ocean. P. b. bailloni Central W indian ocean. mascarene is. P. b. dichrous Tropical S Pacific and Indian Oceans (except Mascarene Is.).

Puffinus subalaris Galápagos Shearwater Galapagos is.

34, 37

Puffinus newelli Newell’s Shearwater

34

Puffinus auricularis Townsend’s Shearwater

34

Puffinus heinrothi Heinroth’s Shearwater

30

P. n. newelli Central N Pacific Ocean. Main Hawaiian Is. P. n. myrtae rapa island in the Austral Group (possibly elsewhere in French polynesia). Eastern N Pacific. Clarión, San Benedicto and socorro is., revillagigedo is. Central W Pacific, W Solomon Is.

Family PELECANOIDIDAE (diving-petrels) Pelecanoides garnotii Peruvian Diving-petrel

38

Pelecanoides magellani Magellanic Diving-petrel

38

Pelecanoides georgicus South Georgia Diving-petrel

38

Pelecanoides urinatrix Common Diving-petrel

38

humboldt current.

magellanic current and extreme se Argentina.

Circumpolar southern ocean in colder subantarctic waters and stewart i. P. u. urinatrix n new Zealand and se Australia. P. u. chathamensis s new Zealand (not subantarctic) and Chatham is. P. u. dacunhae tristan da Cunha is. and Gough i. P. u. berard Falkland is. P. u. coppingeri s Chile. P. u. exsul remainder of subantarctic.

Family HYDROBATIDAE (storm-petrels) Subfamily OCEANITINAE (southern storm-petrels) Oceanites oceanicus Wilson’s Storm-petrel

O. o. oceanicus Breeds on high-latitude subantarctic islands; migrates to N Pacific and Atlantic. O. o. exasperatus Breeds on the Antarctic mainland; migrates to N Pacific and Atlantic. O. o. chilensis Breeds in Chilean fjords; may migrate to N Pacific.

Oceanites gracilis Elliot’s Storm-petrel (White-vented storm-petrel) O. g. galapagoensis (Galápagos White-vented Storm-petrel) Galapágos Islands. O. g. gracilis n Chile and peru.

39

40, 45

Pealeornis maoriana New Zealand Storm-petrel

45

Garrodia nereis Grey-backed Storm-petrel

40

new Zealand waters

Circumpolar subantarctic.



Pelagodroma marina White-faced Storm-petrel

P. m. marina s. Atlantic. tristan da Cunha is. P. m. dulciae sW indian ocean and tasman sea, southern Australia P. m. eadesi Central W Atlantic. Cape Verde Is. P. m. hypoleuca Central W Atlantic. salvages is. P. m. maoriana SW Pacific. new Zealand (other than Kermadec is.). P. m. albiclunis SW Pacific. Kermadec is.

44

Fregetta tropica Black-bellied Storm-petrel

41, 45

Fregetta grallaria White-bellied Storm-petrel

41, 45

F. t. tropica Circumpolar subantarctic. F. t. melanoleuca s Atlantic. tristan da Cunha is. F. g. grallaria tasman sea. F. g. leucogaster s Atlantic. tristan da Cunha is. F. g. segethi SE Pacific, Juan Fernández Is. F. g. titan Central Pacific. Rapa Is.

Nesofregetta fuliginosa Polynesian Storm-petrel (White-throated storm-petrel) Central S Pacific Ocean.

44

Subfamily HYDROBATINAE (northern storm-petrels) Hydrobates pelagicus European Storm-petrel

39

Oceanodroma microsoma Least Storm-petrel

42

Oceanodroma tethys Wedge-rumped Storm-petrel

40

Oceanodroma castro Madeiran Storm-petrel (Band-rumped storm-petrel)

39

n Atlantic; migrates to s. Atlantic.

Mexican Pacific coast; migrates south.

O. t. tethys (Galápagos Storm-petrel) Galápagos Is. O. t. kelsalli (peruvian storm-petrel) peruvian waters Tropical and subtropical Atlantic and Pacific.

Oceanodroma leucorhoa Leach’s Storm-petrel

O. l. leucorhoa N Pacific, N Atlantic and Pacific (except central NE Pacific). O. l. chapmani Central NE Pacific. Baja California. O. l. cheimomnestes Pacific Mexican coast. Guadalupe I. (winter breeder). O. l. socorroensis Pacific Mexican coast. Guadalupe I. (summer breeder).

Oceanodroma monorhis Swinhoe’s Storm-petrel NE Pacific; migrates into N Indian Ocean.

39, 40, 42, 43

43

Oceanodroma macrodactyla Guadalupe Storm-petrel Central NE Pacific. Guadalupe I., probably extinct.

Oceanodroma tristrami Tristram’s Storm-petrel

43

Oceanodroma markhami Markham’s Storm-petrel

42

Oceanodroma matsudairae Matsudaira’s Storm-petrel

43

Oceanodroma melania Black Storm-petrel

42

Oceanodroma homochroa Ashy Storm-petrel

42

Oceanodroma hornbyi Hornby’s Storm-petrel (ringed storm-petrel)

44

Oceanodroma furcata Fork-tailed Storm-petrel

42

NE Pacific. S Japanese Is.

Waters of humboldt current.

NE Pacific, Iwo Jima; migrates to N Indian Ocean. Central NE Pacific. Baja California.

Central NE Pacific. Islands off California coast and Baja California. Waters of humboldt current.

O. f. forcata n Kuril, Commander and Aleutian is. O. f. plumbea Alaska to n California.

10

PREFACE This book covers the 137 currently accepted species of the avian order Procellariiformes, ubiquitous denizens of the oceans of the world. the common name for the entire group is ‘tubenoses’, a reference to their external tubular nostrils, which are often very evident on the upper mandible. the order is usually divided further into four families: the albatrosses, diomedeidae; petrels and shearwaters, the procellariidae; the storm-petrels, hydrobatidae; and the diving-petrels, pelecanoididae. the procellariiformes are an ancient group that have been recognisable in the fossil record for more than 35 million years. the order includes some of the world’s commonest birds, such as Wilson’s storm-petrel. Yet the group’s very existence is scarcely known to the general public, due mainly to the fact that petrels and albatrosses are almost exclusively marine birds, spending the majority of their lives at sea and only coming to land in order to breed. Before the 1980s, observation and identification of petrels had been limited mostly to those who lived and worked at sea, and was hampered by the absence of a good field guide. The landmark publication of Peter harrison’s Seabirds: an identification guide by Croom helm in 1983 began the ‘rush to sea’. in recent years, the advent of ‘pelagic’ birdwatching trips and eco-tourism that reaches the poles and the southern oceans has seen the identification of seabirds become a frontier of birding. Many questions have been answered since the publication of Harrison’s guide, but a number of identification issues remain unresolved, and there are cases in this book where we had to admit that separation of a species at sea is extremely difficult or even impossible given our current knowledge of the group. indeed, even our understanding of what constitutes a species is still in a state of flux. Bird taxonomy cycles through periods of ‘lumping’ and ‘splitting’ of species. The current trend is to split, stimulated by enthusiastic use of genetic research, and nowhere is this more apparent than among the albatrosses; the 14 traditionally accepted species have been split, by some, into as many as 27 separate species. in this book we have tended to be conservative and have leant toward the adage that if you can’t recognise it at sea then don’t separate it. This book is for birders, birdwatchers and others who go to sea and who wish to find and identify the birds that they see there, whether flying alone through storms, feeding en masse in the sun with dolphins, tuna and gannets, or paddling around at the back of a boat waiting for a handout. It is aimed mainly at identifying flying birds and we concentrate on those aspects of plumage, moult, morphometrics and biology that help with this. For example, we include features such as egg-laying dates to give an indication of the time of year the species can be found near land, but we omit details of incubation shifts by males and females. At times we have to discuss plumage in some detail, but we do not go into the meticulous feather-by-feather detail that may enable identification of birds in the hand. We include descriptions of characteristic flight styles but rarely mention voice. most petrels are silent during the day at sea except when they congregate in groups; in our experience, voice is not useful in the separation of any species of albatross or petrel. We recommend that if you wish to find out more about the lives of albatrosses and petrels you take a look at Warham (1990, 1996) or Brooke (2004).

ACKNOWLEDGEMENTS We would like to thank the following people who helped in many ways, by providing such things as accommodation, money, cups of tea, pub lunches, information, photographs, references, permission, discussion, opinions and encouragement, and for doing so cheerfully and generously: sandy Bartle, Kevin Bartram, sharon Birks, mike Carter, George Chance, Joanna Cooper, robert prys-Jones, rose delany, euan dunn, david eades, Jim enticott, dominique Filippi, Brian Gill, Judy Grindell, mike imber, david James, robert Kirk, mary leCroy, douglas J. long, dick newell, Gary melville, Colin miskelly, Gwenda pulham, tim reid, Chris robertson, ilka soehle, paul sagar, sav saville, larry spear, Brent stephenson, paul sweet, Graeme taylor, Alan tennyson, Caz Thomas, Kath Walker, Dick Watling, Eric Woehler, and J. Weick; to all the others we are sure we have forgotten over the last six years, our apologies. special thanks to nigel redman and Jim martin at Christopher helm for their help and advice, and for guiding the book skillfully to publication; thanks also to editors tim harris and John Jackson, and to designer Julie dando. We would also like to thank the following museums and their staff for allowing us access to their collections and providing us with space in which to work: the museum of new Zealand te papa tongarewa; Auckland, Canterbury and otago museums, new Zealand; the natural history museum, tring; the California Academy of sciences, san Francisco; the American museum of natural history, new York; and Burke museum, seattle. We would like to point out that many texts in this book do not agree with the ‘conventional wisdom’ and contradict published identification texts that many birders accept as the ‘truth’. These differences of opinion are based on many hours of observation at sea and detailed examination of museum specimens. We may be wrong in some cases and we accept that any inaccuracies here are our own. We would love to hear from anyone (c/o the publishers) who disagrees with us and welcome a vigorous debate. That is the only way field identification can progress.

11

TAXONOMY AND THE SPECIES DEBATE The classification of birds is traditionally based on an assessment of similarities in morphology, with measurements and plumage being the main considerations, together with additional input from less conveniently studied aspects, such as behaviour, calls, distribution and even lice. those birds that exhibit the least differences are deemed to be the most closely related, and with the study of the fossil record conclusions are possible about their evolutionary history. Before dealing with criticisms of this approach, it should be remembered that for 95% of the time this gives a reasonably clear idea of what constitutes a species and of the relationships between them, and for many birders this is quite adequate.

GENETIC RESEARCH data of a molecular nature, mainly the analysis and comparison of nuclear and mitochondrial dnA, became commonplace about 15 years ago and have added to the information available from traditional methods. it should be stressed, however, that these molecular techniques do not mean that a researcher can clip off a bit of a bird, whether alive, recently dead on the tideline, or long dead in a museum tray, stick it in a machine and get a printout of the species. the technique essentially involves comparing genetic material, much as traditional taxonomists compared morphological data, and coming up with a measure of the degree of separation. then, employing some vigorously debated figures about the rate of molecular evolution, statistical techniques are used to arrive at a phylogenetic tree. or, to be honest, several trees; the techniques are a long way from being as cutand-dried as some biologists would suggest. however, genetic research has unquestionably made valuable contributions to our understanding of seabird phylogeny; we now recognise the importance of convergent evolution in the group, for example, where birds have evolved similar morphologies and behaviours in response to similar environmental cues, but do not share a recent common ancestor. it is also possible, using genetic material such as mitochondrial dnA that mutates at a known rate over the course of millions of years, to quantify the degree of genetic difference between two samples. This allows us to date with a degree of confidence major events in the seabird lineage, such as the divergence of the ancestors of modern storm-petrels and albatrosses some 10 million years ago. Both traditional and molecular techniques come up with measures of the degree of relationship between the birds in question. traditional taxonomists might arrive at what appears to be a complex array of features such as bill measurements, foot colour, and timing of moult and breeding, compared with the apparently neat percentage distances of molecular researchers (e. g. genetic distances within the genus Thalassarche range from 1.66% to 3.15%), but the next step is essentially the same; they have to decide on a degree of difference that will be used to define genera, species, super- and subspecies, and, indeed, whether they are even going to recognise all of these categories. At this point, having perhaps plodded through a number of user-unfriendly scientific papers in order to understand the intricacies of molecular techniques, it would seem quite legitimate for the ordinary birder to quietly despair or yell out loud in anger – biologists can’t even agree on what a species is!

SPECIES CONCEPTS there are several opinions as to what constitutes a species. perhaps the simplest in concept, if not in name, is the phylogenetic species Concept, as summarised by Cracraft (1983). it gives species status to any group of birds that are morphologically distinguishable. in this scheme of things the pale-faced subantarctic race of Fairy prion would become a full species, Pachyptila subantarctica, equal in status to the big, dark-billed Broad-billed prion P. vittata; but for its english name, all trace of the closer relationship with Fairy prion would be lost. thus the psC conceals a lot of useful information; several authors have tried to deal with this problem and subsequently added to the confusion. An alternative approach is the Biological species Concept, as advocated by ernst mayr, which maintains that ‘species are groups of interbreeding natural populations that are reproductively isolated from one another’. At first glance, this seems a more sensible point of view as a statement of what everyone understands as a species; albatrosses are obviously different from storm-petrels. In molecular terminology, there is no gene flow between the populations. For the majority of cases the BSC works well. It does, however, run into difficulties with populations that have recently diverged and may still interbreed, or are morphometrically or genetically similar but have ranges that do not overlap, a frequent occurrence with albatrosses and petrels that nest on isolated islands. this problem led biologists to expand the BsC into a multidimensional Biological species Concept (mBsC), which allows the combination of similar populations into polytypic species. there is a ‘political’ element to this debate. in developed countries, conservation funding has been forthcoming for endangered species, especially if they can be shown to be endemic. For example, the promotion of the shy Albatross that breeds in Bass strait to full species status (as White-capped Albatross T. cauta) would allow the Australian government to fund research and conservation efforts. this is much less likely to happen if

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the taxon remains a subspecies of Shy Albatross, which also nests in New Zealand. According this taxon specific status would be an understandable and worthy move given the dearth of conservation funding, but it would not necessarily reflect well on scientific integrity, nor would it help our understanding of the debate. it was the adoption of the narrowest psC that led robertson and nunn (1998) to increase the number of albatross species from 13 to 24, and to happily accept nucleotide distances of less than 1% as indicative of specific species. Recent workers and reviewers, however, have tended to view the same albatrosses through fuzzier MBSC glasses, and have rejected any distances of less than 1% as indicative of specific status, ending up with 13 to 22 species. Even when there is agreement on the definition of a species, the criteria for raising a group of birds to species status vary considerably between authors. For example, for many years the Atlantic members of the genus Calonectris have been lumped together under the name Cory’s shearwater (C. diomedea). this despite the fact that the birds from the Cape Verdes are obviously a lot smaller, have slimmer, greyish rather than yellow bills, and breed later and entirely separately from the rest. Most authors now accept that Cape Verde Shearwater should be raised to species status (C. edwardsii), though Brooke (2004) is not entirely convinced. there are also differences between those populations of Cory’s shearwater that breed in the mediterranean and those that breed on the Atlantic islands; those from the mediterranean are smaller on average, with paler underwings and paler heads. Most authors accept that these populations warrant subspecific status, but only the most enthusiastic ‘splitters’ make a case for full species status. the only genetic work carried out so far on this group is by penhallurick and Wink (2004) and unfortunately they did not include the Cape Verde birds. They interpreted their results for the Atlantic and Mediterranean populations as not warranting specific status but other workers in the field have used what appears to be the same or even a lesser degree of genetic difference as evidence to support such status.

CONCLUSIONS there is no doubt that genetic work has added new information to the taxonomic debate, but interpretations of the data still remain a matter of opinion; some have been dogged by poor science, and are far from being the revolution that enthusiasts have claimed. the debate is not over, but it is also worth remembering that the taxonomic status of the majority of albatrosses and petrels had remained much the same for 70 years, and those that have changed have, in most cases, been recognised as different species or as a subspecies for some time. there have not been that many surprises! Amidst all this debate we had to make some broad decisions on taxonomy and on which taxonomic sources to follow – after all, field guides are about identifying birds to species. So for much of this book we have followed Brooke (2004), only departing substantially when we get to the smaller shearwaters, where we have adopted many of the recommendations of Austin et al. (2004).

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THE FOUR FAMILIES: CHARACTERISTICS AND TAXONOMIC RELATIONSHIPS A combination of evidence from molecular studies and the fossil record suggests that petrels emerged from a common ancestor (with penguins and divers) in the mid-eocene, some 40–45 million years ago, and the four modern families, diomedeidae, procellariidae, hydrobatidae and pelecanoididae, were present 10 million years later in the Oligocene. Storm-petrels diverged first, then albatrosses, so storm-petrels are thus rather surprisingly more closely related to the albatrosses than to the petrels, shearwaters or diving-petrels.

ALBATROSSES (DIOMEDEIDAE) Albatrosses are big, far bigger than all other procellariiforms bar the giant petrels. they weigh between 2 and 9kg and have wingspans of between 1.8 and 3.5m. Unlike the other three families, they have separate nostrils on either side of the bill. the long, narrow wings with low wing-loading (low weight-to-wing area ratio) are ideal for extended gliding flights, and they fly huge distances in search of food. Albatrosses feed by landing on the sea and grabbing prey at or near the surface, and all but the sooty albatrosses are attracted to fishing boats. Rather than occupying burrows, they nest on the surface.

Snowy Albatross

separate nostrils

Following molecular studies by nunn et al. (1996) and nunn & stanley (1998), it is now generally accepted that the albatrosses can be divided into four genera. These are the North Pacific albatrosses (Phoebastria), the great albatrosses (Diomedea), the mollymawks (Thalassarche), and the sooty albatrosses (Phoebetria). it is also generally agreed that the genus Phoebastria consists of four species, laysan, Waved, short-tailed and Black-footed Albatrosses, while Phoebetria contains just two, the sooty and light-mantled Albatrosses. however, the make-up of the other two genera is more contentious. robertson and nunn (1998) suggested increasing the number of species in Diomedea and Thalassarche from 10 to 18. this scheme was widely adopted despite the fact that supporting evidence remained unpublished for some time. in this guide we have accepted six species in Diomedea; snowy, new Zealand, tristan, Amsterdam island and northern and southern royal Albatrosses, and nine in Thalassarche: Black-browed and the very similar but yellow-eyed Campbell Albatrosses, shy, salvin’s and Chatham islands Albatrosses, and both indian and Atlantic Yellow-nosed Albatrosses. however, we treat Buller’s Albatross and the darker-headed birds from the Chatham islands as one species. Grey-headed Albatross remains, as always, as one species.

STORM-PETRELS (HYDROBATIDAE) storm-petrels are the smallest of all the oceanic birds, weighing from 20g (a third less than a house sparrow) to just over 100g, with wingspans of 32–56cm. they have relatively short inner wings, a large area of primaries and a low wing-loading so they can glide well yet remain manoeuvrable. they feed by picking small prey off the surface of the sea, fluttering and swooping low over the sea, and often pattering their feet upon the surface. Most breed in natural holes and crevices rather than digging burrows, and all but the Wedge-rumped storm-petrel on the Galápagos visit their breeding grounds only at night.

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the family is divided into two subfamilies: oceanitinae (southern hemisphere), 8 species in 6 genera Wilson’s storm-petrel (Oceanites oceanicus) elliot’s storm-petrel (Oceanites gracilis) new Zealand storm-petrel (Pealeornis maoriana) Grey-backed storm-petrel (Garrodia nereis) White-faced storm-petrel (Pelagodroma marina) Black-bellied storm-petrel (Fregetta tropica) White-bellied storm-petrel (Fregetta grallaria) polynesian storm-petrel (Nesofregetta fuliginosa)

Grey-backed Storm-petrel

hydrobatinae (northern hemisphere), 14 species in 2 or 3 genera but with 13 species often placed in one genus, Oceanodroma european storm-petrel (Hydrobates pelagicus) least storm-petrel (Oceanodroma (Halocyptena) microsoma) Wedge-rumped storm-petrel (Oceanodroma tethys) madeiran storm-petrel (Oceanodroma castro) leach’s storm-petrel (Oceanodroma leucorhoa) swinhoe’s storm-petrel (Oceanodroma monorhis) tristram’s storm-petrel (Oceanodroma tristrami) markham’s storm-petrel (Oceanodroma markhami) matsudaira’s storm-petrel (Oceanodroma matsudairae) Black storm-petrel (Oceanodroma melania) Ashy storm-petrel (Oceanodroma homochroa) hornby’s storm-petrel (Oceanodroma hornbyi) Fork-tailed storm-petrel (Oceanodroma furcata) Guadalupe storm-petrel (Oceanodroma macrodactyla)

Leach’s Storm-petrel

recent molecular data has supported the retention of all the species and the southern-hemisphere genera, but more work is required.

DIvING-PETRELS (PELECANOIDIDAE)

Common Diving-petrel

A group of four very similar, small, southern-hemisphere species that in many ways are more like the auks of the northern hemisphere than the rest of the petrels. they weigh between 100 and 200g, have two small nostril openings on top of the bill, and have small, rounded wings with a high wing-loading. They fly directly with rapid, whirring wings, and feed by diving, propelling themselves underwater with half-closed wings. Unlike many other petrels they tend to live and feed near their nesting areas and appear to have relatively short lifespans. diving-petrels dig burrows or nest in natural holes and only visit breeding colonies at night. there are four species in one genus, Pelecanoides. darwin, amongst others, wondered about their affinities with the auks but nowadays they are taxonomically uncontroversial.

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PETRELS AND SHEARWATERS (PROCELLARIIDAE) Compared with the other three families, the procellariidae are a rather diverse assemblage. the 80 or so species (there is considerable taxonomic debate) are usually divided into four subfamilies: the fulmarine petrels, the prions, gadfly petrels and shearwaters.

Fulmarine petrels

the fulmarine petrels are a small but diverse group ranging in size from the 250g Snow Petrel to the 5kg giant petrels, which are smaller only than the larger albatrosses. Fulmarine petrels exhibit a wide range of plumages, from the entirely white snow petrel, through the grey, gull-like fulmars and chequered black-andwhite Cape petrel to the variably brownish giant petrels. Fulmarine petrels all have prominent nasal tubes on top of the bill. they feed by landing on the sea and seizing prey near the surface. Northern Fulmars, Cape Petrels and giant petrels feed around fishing boats; uniquely among procellariiforms, giant petrels may feed on land, scavenging around seabird and seal colonies. snow petrels nest in crevices, but all the others nest on the surface or on cliff ledges, and all visit the breeding grounds by day. taxonomically, the Antarctic and Cape petrels and the two fulmars are relatively uncontroversial, although there is some debate over subspecies of the northern Fulmar, which exhibits several colour morphs and has separate populations in the Pacific and Atlantic Oceans. taxonomic debate continues as to whether the snow petrel should be split into two species, Greater and lesser, and whether it is more closely related to the Kerguelen petrel than to the fulmarines. the two giant petrels are normally recognised as distinct species

Prions

Northern Giant Petrel

Cape Petrel

the prions are a distinctive group of small, blue-grey petrels of the cooler southern oceans. they weigh between 90 and 240g. All have distinctive bills with fine filters called lamellae along the edge of the upper mandible, and a gular pouch. These are used to filter out plankton in the manner of a baleen whale. Prions feed by sitting on the sea or by flying low over the surface, often using their feet to bounce off waves not unlike a storm-petrel. At sea, all but slender-billed and Fulmar prions are often highly gregarious and can be seen in huge flocks, but they rarely follow ships or feed around fishing vessels. prions nest in burrows and crevices. Fulmar prions can be seen on the breeding grounds during the day but all others visit only at night. Slender-billed Prion most authors accept that Fairy and Fulmar prions form a separate grouping from the rest but taxonomists agree about little else. the situation is complex; morphometric measurements overlap a lot and each island population of the ‘same species’ is slightly different, so much so that earlier authors regularly named prions by the island the specimens came from. the situation may become clearer when good samples of genetic and morphometric data are available from known breeding birds on a wider range of islands, and more details of breeding biology (notably of hybridisation) are better known. For this book, we recognise seven species in one genus, Pachyptila, and mention Broad-billed Prion seven further subspecies.

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Gadfly petrels The term gadfly petrel has been used to describe a diverse group of longwinged, fast flying, medium-to-small, highly pelagic species of temperate and tropical oceans. All feed on the wing, and they can even catch flying fish. They also alight on the sea and scavenge or grab prey at or near the surface. species that breed in the cooler oceans tend to nest in burrows or crevices and visit their colonies by night, while those in the tropics are more likely to nest on the surface and be active at the colony during the day. Gadfly petrels rarely feed around fishing vessels. We have used the term gadfly petrel to refer solely to species in the genus Pterodroma but other authors also include the genera Lugensa, Pseudobulweria and Bulweria. the genus Lugensa consists of only one species, Kerguelen petrel, which, despite being only relatively recently removed from Pterodroma, appears to be quite distinct and with no obvious close affinities. the genus Bulweria has been recognised as distinctive for a fair while and contains two species, Bulwer’s and Jouanin’s petrels. Both are dark, long-winged and long-tailed tropical species that have characteristic bills with less obvious tubular nostrils than the Pterodroma petrels. like Bulweria, the genus PseudoTahiti Petrel bulweria occurs in warmer seas, and Bulwer’s Petrel its species are long-winged and longtailed, with deep, heavy bills. the genus includes four species, Fiji and mascarene petrels, the larger tahiti petrel, and the very similar but smaller Beck’s petrel. the genus Pterodroma contains 30–35 species, all of which have relatively short, strong bills with prominent nasal tubes and a hooked tip. they range in plumage from entirely dark, through several species that have dark and light phases, to a distinctive group that are white underneath and pale grey above with a dark m mark across the open wings. the smaller members of this distinctively marked group are often collectively called the cookilarias.

Great-winged Petrel

Stejneger’s Petrel

Barau’s Petrel Kermadec Petrel

the pterodromas, especially those from the warmer oceans, are neither well-known nor well-studied, and several new species have recently been ‘discovered’ rather than promoted purely on the basis of molecular and taxonomic re-evaluation. these include the henderson petrel, ostensibly a dark form of herald petrel but which breeds separately from all the light forms on henderson atoll in the pitcairn Group, and a small form of Whitenecked Petrel, Vanuatu Petrel, which was described from old museum specimens and a more recent storm-blown corpse from Australia. Current taxonomic discussion centres on the long-assumed relationship between the north Atlantic Fea’s and Zino’s petrels with the southern ocean soft-plumaged petrel (Fea’s actually seems to be more closely related to Cahow than Soft-plumaged Petrel), and the specific status of the polymorphic Herald/Trindade group that breeds on widely separated islands in the Atlantic, Indian and Pacific Oceans. We have accepted all the recent ‘splits’ and recognise a total of 35 species in the genus Pterodroma.

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Brooke (2004) includes the five members of the genus Procellaria among the shearwaters, but although they possess the ability to dive, their bills are deep and strong with large hooked tips and prominent nasal tubes, more like the pterodromas. the Procellaria are the largest of the burrowing petrels, ranging in weight from 600–700g for parkinson’s petrel to 1.5kg for White-chinned petrel.

Shearwaters

the two genera of shearwaters, Calonectris and Puffinus, are small to medium-sized shearwaters with relatively long, slim bills that have less prominent nostril tubes and shallower hooks on the tips than the pterodromas. the smallest shearwaters weigh 150g and the largest more than 1kg, with many species being in the 300–400g range. All dive for food to some extent; Cory’s shearwater rarely reaches 5m under the surface, but sooty and short-tailed shearwaters are capable of depths of 70m and swim well underwater, propelling themselves on half-open wings. those that dive well, especially the smaller Puffinus species, have compressed, water-resistant plumage, narrower, more streamlined bodies, flattened tarsi, and short, narrow wings with stiffer, stronger primaries. these adaptations all facilitate swimming and chasing prey underwater. the larger species, especially Wedge-tailed and Buller’s shearwaters and those in the genus Calonectris, have broader wings and longer tails, are much more manoeuvrable, and take much of their food on the wing or by shallow plunge-diving. many of the shearwaters feed around fishing boats. Shearwaters that breed in temperate areas dig burrows and visit colonies by night, but a few in the tropics nest on the surface and are present at colonies by day. Streaked Shearwater

Fluttering Shearwater

Flesh-footed Shearwater

A version of the smaller, manx-like, brown or black-and-white Puffinus shearwater occurs throughout the world’s temperate and tropical oceans, nesting on many oceanic islands and archipelagos and on islands on continental shelves. they have provided taxonomists with many hours of amusement, caused much constructive discussion and bitter controversy, and even generated a little in the way of research funds. one set of labels on a brownish, rather faded and admittedly intermediate looking specimen (in a well-known museum that should perhaps remain nameless) had no fewer than seven pencilled amendments culminating in ‘atrodorsalis?’. once everyone, more or less, agreed that there was a relatively easy-to-identify manx-type group of species, discussion moved on to centre around what became known as the little/ Audubon’s shearwater complex. the ‘little’ end of the spectrum was characterised by black upperparts, a short tail, white undertail, smallish Westland Petrel bill and steep forehead; the ‘Audubon’s’ end by brown upperparts, long tail, dark undertail, biggish bill and sloped forehead. it was the intermediates, notably from the Atlantic islands, plus poorly studied representatives from far-flung Pacific and Indian Ocean islands, distant from the centres of taxonomic debate in europe and the UsA, that caused the controversy. recent molecular studies, especially those by Austin et al. (2004), suggest that this emphasis on the characters differentiating little from Audubon’s was misleading, as were many of the island species and subspecies, and that the group was better looked upon as three biogeographic groups – from the north Atlantic, southern oceans including Australasia, and the tropical Indian and Pacific Oceans respectively. Intriguingly, one of the consequences of this research is that little shearwater characteristics (black upperparts, short tail etc.) appear to have evolved separately and convergently in the northern and southern hemispheres, and are not an indication of a close relationship.

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The Little/Audubon group. Left – Little characteristics; centre – intermediate; right – Audubon’s. Genetic studies have shown that these morphometric characteristics do not truly reflect specific status.

We agree with many of Austin et al.’s (2004) recommendations; see the main text for details. We have decided to include a total of 10 species from the former little/Audubon’s shearwater complex. together with the manxtype group this makes 16 smaller Puffinus shearwaters, and 28 species of shearwaters in total (three in Calonectris and the rest in Puffinus).

IDENTIFICATION Away from their breeding grounds, from the shore or at sea, the usual view of an albatross or petrel is fleeting and in flight. Things get a little easier if members of the species are attracted to ships, and an outing on a fishing boat or, even better, a pelagic birding trip will bring many species in close enough to allow excellent views of birds in flight and on the water. This is especially true of many of the albatrosses and a fair number of the shearwaters, but many of the storm-petrels and gadfly petrels, especially those from warmer seas, are rarely attracted to ships and remain elusive. in the main text we mention those species that are attracted to boats and to ‘chum’, that enticing concoction of oily, smelly, fishy stuff thrown off the back of boats by pelagic birders to attract seabirds close enough to allow identification. In this guide we concentrate on the identification of birds in flight. This section deals with some of the problems and pitfalls associated with assessing a bird at sea. Identification of many albatrosses and petrels is not easy and there is no simple substitute for comparative experience. the best observers often identify a bird by jizz, a term birders use to describe the general impression created by a bird’s outstanding features, shape and relative proportions. it can be looked upon as the ‘arty’ side of birding. it is the aspect of a bird that allows an experienced birder to identify a species from a brief glance out of the corner of their eye without quite knowing how they do it. Equally, it allows the less scrupulous to mumble ‘jizz’ and claim an identification based on the most fleeting of glimpses and on the slightest of pretexts.

PHOTOGRAPHS AND vIDEO there is no doubt that photography, and especially the recent rapid rise of digital technology, has contributed enormously to our knowledge of seabird identification; it would have been much more difficult to produce the illustrations for this book without hundreds of reference photographs. looking over the day’s crop of photos and videos in the evening has even led to the discovery of rare and unusual species that were not noticed at the time among all the activity around the boat. The first indication that the New Zealand Storm-petrel was not long-extinct came from the discovery in this manner of an otherwise unnoticed, white-rumped storm-petrel in a set of photographs. on the other hand, photographs (especially single ones) can be very misleading. most birders realise that a single shot can capture a bird in an uncharacteristic pose; this is especially true of seabirds in flight and many birders are now aware of the problems of assessing size in photographs. Not only is there often nothing that can be used as a reference point in a closely cropped view of a bird, but photos taken through a telephoto lens create the impression that objects further away are larger than they actually are. telephoto images are now so commonplace that we automatically compensate for this compression of perspective, but look closely at many

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a picture of a flying albatross and you can see that the near wing is narrower and smaller than the far wing – not a natural state of affairs. Add to these difficulties all those related to weather and lighting (see below under Conditions) plus a camera’s shortcomings in faithfully reproducing colour and contrast, and those single photographs can result in many hours of entertaining yet often fruitless debate. the immediate reaction of seabird experts to mystery photos these days is to ask for more information. how big was it? What was its underwing, upperparts, rump like? How did it fly? Almost inevitably the information is not forthcoming and here we would like to make a plea. please, please take the time to observe the birds and take notes as well as looking through a camera lens. A few more seconds of observation of that mystery Pterodroma you photographed and you would have known whether it had a white rump, if that really was a pale nape or whether it was just a bright patch of light contrasting with the dark underwing shadow. photographs are helpful but they cannot stand alone and require good observation and documentation if they are to be really useful.

CONDITIONS Weather, lighting and sea conditions can alter the appearance of a bird. For example, in dull and rainy weather many seabirds will look dark against the sea and sky, even when your binoculars are not misted up. Bright sun increases the contrast between lighter and darker areas, shadows can appear as dark plumage features, and sunlight glinting on dark feathers, especially worn ones, can make them appear very pale. in bright sunny conditions, light reflecting off the surface of the sea can make all underparts look pale; this can make things especially difficult when trying to see the pattern on the underwing of a Pterodroma petrel. the diagnostic dark bars on the mainly white underwing of cookilaria petrels can be lost in a white glare and the subtle pale patches on the base of the primaries of murphy’s petrel can look almost as white as those on herald petrel. the direction of the light is also important. Back-lit birds will look darker, plumage details will be obscured, yet light may shine through spread wing- and tail-feathers and make them appear paler than Cook’s Petrel they actually are. light from the side or from behind the observer is usually best, but it can also wash out details and make everything look pale. Wind strength can dramatically alter the way a species flies, and diagnostic flight patterns may no longer apply. For example, in high winds the characteristic low, fluttering flight of the smaller shearwaters can turn into speedy, wheeling arcs, more Murphy’s Petrel like the typical flight of a Pterodroma; in calm conditions, a Kermadec Petrel can fly with strong wingbeats The same Cook’s Petrel, back-lit on the left, lit from the side on the right. Murphy’s not unlike a skua. Petrel with light reflecting off the sea.

SIzE The Procellariiformes are quoted as having the greatest range in size of any avian order. The smallest species, least storm-petrel, weighs a mere 28–34g and has a 32-cm wingspan, while the largest, snowy Albatross, weighs 11kg and has a wingspan of up to 3.6m. thus the largest is 25 times greater in wingspan and 274 times heavier than the smallest. despite this, and due to a lack of landmarks on the ocean surface, judging the distance an object is from a ship at sea is fraught with difficulty. Because of this, among many other reasons (not least of which is seasickness), even the most experienced of observers may have difficulty estimating the size of a bird at sea. If at all possible, the best thing to do is to compare an unknown bird to another identifiable species visible at the same time. Experienced observers often get an idea of size by a feeling for the flight style of a bird. Albatrosses, for example, wheel slowly above the horizon on motionless wings, while smaller species appear suddenly and disappear just as swiftly. Size often varies a lot within a species. Males are often considerably larger than females, and in the few species where size is a useful identification feature this can lead to errors. For example, exercise caution when using size to differentiate the wandering and royal albatross species and the black Procellaria petrels, as there is considerable interspecific overlap and intraspecific variation. Often it is the proportions, such as bill length, robustness of head, or overall length, that are more useful than length or wingspan alone. Size is often one of the first things inexperienced observers try to assess, but it is usually better to concentrate first on the plumage features, style of flight and proportions – almost anything else, in fact, apart from size – if you are to make the most of a fleeting encounter.

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PLUMAGE Plumage variation, phases and morphs twenty or so of the petrel and albatross species regularly show some from of plumage variation that can be easily seen in the field, but only half of these are usually considered to have distinct phases or morphs. those that show a wide range of plumages from light to dark with a full range of intermediates include one fulmarine petrel, the northern Fulmar; four gadfly petrels, the herald, trindade, Kermadec and Collared petrels; one shearwater, Wedge-tailed shearwater; and two storm-petrels, White-bellied and polynesian. examples of lesser degrees of variation include the Wedge-tailed Shearwater; light, intermediate and dark morphs. southern Giant petrel which has a relatively common white phase, all other variation in the dark phase being age-related. the soft-plumaged petrel has a very rare dark phase and there are a few intermediates in museum collections, but there have been no recent records of such birds at sea. museum specimens of Atlantic petrel also show a surprisingly wide range of plumages, including almost entirely dark birds but, as with soft-plumaged petrel, these are rarely recorded at sea nowadays. Both may be cases of selective collecting resulting in an over-representation of unusual birds in collections; alternatively, the specimens may have been taken from more variable populations that are now extinct. elliot’s storm-petrel comes in dark and lighter-bellied forms, but these are geographically separated and are usually regarded as subspecies, while the Pacific forms of Leach’s Storm-petrel show a cline of increasingly dark-rumped birds, correlated with the distance south that they breed along the American coast. From an identification point of view it is always necessary to be aware of the wide range of plumages among these variable species, but in only a few cases does identification become difficult or impossible. The dark phases of White-bellied, polynesian and leach’s storm-petrels have to be remembered when trying to sort out an all-dark storm-petrel, but range and jizz coupled with a fair amount of experience should allow identification. on the other hand, some intermediate phases of Collared petrel may not be distinguishable from Gould’s petrel; similarly, the henderson petrel does not appear to be distinguishable at sea from the dark phases of herald and trindade petrels.

Age-related plumage variation

From an identification point of view, age-related plumage changes are only really a problem among the albatrosses. the most extreme variation occurs juvenile in the short-tailed Albatross and in the wandering albatross group, where juveniles are almost entirely chocolate-brown on fledging and take several years to attain the paler and whiter adult plumages. the process is especially complex and variable among adult the wandering albatrosses. now that the group has been divided into a number of species, identification has become very difficult if not impossible. We have covered this complicated issue at some length in the main text. At fledging young mollymawks are superficially similar to the adults, but generally have scruffier heads, duller bills and, in a few cases, darker underwings. Identification involves careful observation and Plumage varies with age in Snowy Albatross. comparison of these features. Unlike many of the albatrosses, only the largest of the petrels, the northern and southern Giant petrels, have a markedly different juvenile plumage. like the Albatrosses they also take several years to attain adult plumage and go through a variety of intermediate plumages. some of the intermediate plumages make it more

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difficult to distinguish between the two species but there are no difficult identification consequences, except that a wholly dark juvenile giant petrel may at first glance be confused with a variety of other dark petrels and albatrosses. Size and the distinctive giant petrel shape should soon distinguish them. immature or darker adult Northern Giant Petrel

adult Grey-headed Albatross

juvenile Northern Giant Petrel immature Grey-headed Albatross

Adult and young mollymawks, such as Grey-headed Albatross, have similar plumages. Giant petrels have a range of plumages, like the great albatrosses.

other petrels exhibit only minor differences between juveniles and adults. Juveniles of several species of dark shearwater and storm-petrel tend to have small white tips and narrow fringes to the feathers, especially of the upperparts. Juvenile Pterodroma petrels tend to have broader, paler fringes to feathers; cookilarias especially can look very pale, as can young prions. In general, juvenile plumage does not cause many identification difficulties at species level although the recent discovery that juvenile hutton’s shearwaters have a paler underwing that approaches that of the sympatric Fluttering shearwater suggests that further study may be warranted. Juvenile Little Shearwater

Juvenile Cook’s Petrel

Juvenile Fairy Prion

Juvenile Little Shearwater with white tips to coverts; pale juvenile Cook’s Petrel; juvenile Fairy Prion.

Fresh and worn plumages petrels are not brightly coloured birds; a dash of yellow on the neck of a few albatrosses is about all the deviation one sees from blacks, whites, greys and browns, so you would be right not to expect much difference between fresh and worn plumages. however, it is mainly because so many petrels have similar patterns of blacks, whites and browns that small changes in colour and pattern due to feather abrasion or the acquisition of fresh plumage can cause difficulties with identification. Few identification guides have dealt with these problems; in this guide we mention moult and wear cycles for most species, and many plates have examples of worn and fresh plumages. Below are some examples of the main changes in appearance that occur with feather wear. the state of plumage wear can also be used to age birds, even in the field, and such information can help with identification and contribute to our knowledge of these little-studied species.

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(A) Dark feathers become browner and paler most dark feathers are bleached by sunlight and abrasion and can even result in unusual pale patches and panels, especially on the upperwings. these rarely cause many identification problems but less extreme bleaching could make it difficult to separate the blacker upperparts of tropical shearwater from the browner tones of Arabian shearwater, for example.

fresh

worn

(B) Pale or white feather tips wear off in juvenile or fresh plumage several of the shearwaters and storm-petrels have narrow white fringes or tips to the dark feathers of the upperparts. in the case of shearwaters this (A) rarely causes any identification problems but in storm-petrels, especially those where identification relies on the extent and distinctness of the pale Fluttering Shearwater crescentic upper wingbar, this could cause confusion. Some of the greyer or paler phases of gadfly petrels can have broad pale fringes to upperpart feathers in fresh plumage, and this can make fresh birds appear very pale. Where identification includes assessment of subtle differences in colour and tone, as for example in the cookilaria group, these pale, often juvenile, birds can cause problems. worn Relying on narrow fringes to any feathers for identification is not recommended and can be misleading. For example, differences in the extent of white feathers on the scapulars can be diagnostic in diving-petrels; even the peruvian species with the most extensive white markings can lose them (B) completely with wear. (C) Grey feathers become darker and browner the pale grey feathers of many Pterodroma petrels become darker and browner with wear. the upperwing is especially likely to become dark and the diagnostic m mark across the open wing is often obscured, or disappears completely. Back and head feathers can take on a scalloped appearance and can cause Peruvian Diving-petrel identification problems, especially amongst such similar species as the small cookilaria petrels. The effect of wear can vary between individuals and flocks of the same species may show a wide variety of plumages. worn Cook’s Petrel fresh

Murphy’s Petrel

fresh

worn

(C)

(D)

Atlantic Petrel

(E)

fresh worn

(D) Dark feather tips wear off to reveal pale bases to feathers many petrels have white or pale bases to dark feathers, but in most species it is only in extreme cases of plumage wear that they are revealed as pale patches. A few species, such as the Antarctic petrel and the dark, immature wandering albatrosses regularly become pale and patchy due to this form of abrasion, but in only a few species, such as the odd pale-chinned Atlantic Petrel, is it likely to cause identification problems. (E) Greyish or silvery sheen on fresh dark plumage wears away in fresh plumage many pterodromas have a greyish or silvery sheen on the feathers, especially on the back, rump and scapulars. At sea these can appear pale and can contrast with darker feathers, resulting, for example, in a more obvious m mark across the upper wing. the sheen disappears with wear and the plumage may become browner with the m marking less distinctive.

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MOULT We have attempted to summarise published information. moult data for many petrels is lacking, yet in many cases detailed study of the moult of individuals of difficult-to-identify species may be helpful in separating them, especially when they are in wing moult at different times of the year. We believe that body moult is far more prevalent than most authors suggest, and many species begin body moult whilst breeding. in many cases the state of moult, and especially body moult, can be used to separate adult from immature birds, and subsequently assist with identification. In most species body moult, apart from occasionally resulting in a rather scruffy, mottled appearance, rarely causes identification problems. the speed with which wing and tail feathers are moulted varies between species. Generally speaking, those that rely on flight to search for food replace their feathers more slowly than those that dive for food. Thus albatrosses replace flight feathers in groups; up to five generations of flight feathers can be identified along the wings of a wandering albatross.

An immature Black-browed Albatross with old, worn outer primaries will be 36–47 months old.

Southern Giant Petrels in wing moult.

several of the mollymawks can be aged by close examination of old and new feathers. in some cases, immature Grey-headed and Black-browed Albatrosses, for example, the distribution of new and old feathers in the wing can aid identification. Giant petrels have such an extended moult of flight feathers that it can sometimes be difficult to see a bird with a complete set of wing feathers. At the other extreme, diving-petrels lose and replace almost all their wing and tail feathers within a few weeks. Pterodroma petrels like soft-plumaged petrel, and the broader-winged shearwaters like Cory’s, can have substantial gaps in their wings yet still fly, whereas the fulmarine Antarctic Petrel can look distinctly pale and scruffy and can be seen sitting around in flocks on the ice while moulting. Soft-plumaged Petrel Antarctic Petrel Elliot’s Storm-petrel

Cory’s Shearwater

The effects of moult on plumage.

From the point of view of identification, petrels in wing moult can cause confusion at first glance because they fly somewhat differently or look a different shape to normal.

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those species that lose their feathers quickly can often show pale panels, especially on the upperwing where absent feathers have revealed pale bases or quills in adjacent feather tracts. the resulting pattern can be unfamiliar and a bird with areas of worn and new feathers and active wing and tail moult can look very odd at first glance. however, as with mollymawks, the presence of wing moult is more likely to assist than hinder identification, since several similar-looking species moult at different times of the year. For example, separating the all-dark Westland petrel from parkinson’s and White-chinned petrels is quick and easy if the birds are in wing moult.

Moulting Jouanin’s Petrel with pale crescent on upperwing like Bulwer’s Petrel.

White-faced Storm-petrel in moult.

CONSERvATION in terms of extinctions, the petrels and albatrosses appear to have fared relatively well in the 10,000 or so years since the last Ice Age. Studies of subfossil remains suggest that only around half a dozen or so have become extinct in that time; five shearwaters from the Canaries, St Helena and New Zealand, and a gadfly petrel from hawaii. in historical times only the Guadalupe storm-petrel has apparently become extinct (though the Jamaican Petrel is either extinct or very nearly so); given that storm-petrels are notoriously difficult to find and the potential breeding habitat is rugged and tropical, the Guadalupe storm-petrel may well ‘return’ like the recently rediscovered new Zealand storm-petrel. Compare this record with the extinction of 30–40 species of land birds since the arrival of polynesian peoples in new Zealand alone, plus a further nine species since the colonisation of the islands by europeans, and the petrels look to be survivors. Brooke (2004) gives the conservation status for 125 species of petrel and albatross based on the series of iUCn categories that assess the level of threat of extinction. Five categories range from ‘least concern’, which suggests everything is generally alright at the moment, to ‘critical’, which indicates imminent extinction (a category that interestingly includes Guadalupe storm-petrel). the criteria for these categories are complex and consist of considerably more than an estimate of numbers. For example, Black-browed Albatross is one of the commonest albatrosses with an estimated three million breeding pairs, yet it is classified as endangered because studies have shown declines of up to 17% over the last two decades, a level that will inevitably lead to extinction if not halted. table 1 below summarises the criteria for the three main categories of concern. Brooke uses two additional categories; ‘near threatened’, which is defined as those species that are close to qualifying for the threatened categories, and ‘data deficient’ which hopefully is self-explanatory, but unfortunately includes some of the more interesting species like Hornby’s Storm-petrel that occur in less accessible and less affluent parts of the world.

Rapid decline Small range fragmented, declining or fluctuating

CRITICAL

ENDANGERED

vULNERABLE

>80% over 10 years or 3 generations

>50% over 10 years or 3 generations

>50% over 20 years or 5 generations

Extent of occurrence