(ISBN: 0-943610-39-7) THE MARINE ECOLOGY OF BIRDS IN THE ROSS SEA, ANTARCTICA BY DAVID G. AINLEY, EDMUND F. O'CONNOR AND ROBERT J. BOEKELHEIDE Point Reyes Bird Observatory Stinson Beach, California ORNITHOLOGICAL MONOGRAPHS NO. 32 PUBLISHED BY THE AMERICAN ORNITHOLOGISTS' UNION WASHINGTON, D.C. 1984 THE MARINE ECOLOGY OF BIRDS IN THE ROSS SEA, ANTARCTIC ORNITHOLOGICAL MONOGRAPHS This series,published by the American Ornithologists'Union, has been estab- lished for major papers too long for inclusion in the Union's journal, The Auk. Publicationhas been made possiblethrough the generosityof the late Mrs. Carll Tucker and the Marcia Brady Tucker Foundation, Inc. Correspondenceconcerning manuscripts for publication in the seriesshould be addressedto the Editor, Dr. Mercedes S. Foster, USFWS, National Museum of Natural History, Washington, D.C. 20560. Copies of OrnithologicalMonographs may be ordered from the Assistantto the Treasurerof the AOU, Frank R. Moore, Departmentof Biology,University of SouthernMississippi, Southern Station Box 5018, Hattiesburg,Mississippi 39406. (See price list on back and inside back covers.) Ornithological Monographs,No. 32, x + 97 pp. Editor of AOU Monographs, Mercedes S. Foster SpecialReviewers for this issue,John P. Croxall, British Antarctic Survey, Cambridge, England; Peter A. Prince, British Antarctic Survey, Cam- bridge,England; George E. Watson,Division of Birds,National Mu- seum of Natural History, Washington, D.C. Authors, David G. Ainley, Edmund F. O'Connor, and Robert J. Boekel- heide, Point ReyesBird Observatory,Stinson Beach, California 94970 First received, 21 April 1982; accepted 27 October 1982; final revision completed, 10 August 1983 Issued February 23, 1984 Price $9.00 prepaid ($8.00 to AOU members). Library of CongressCatalogue Card Number 84-70267 Printed by the Allen Press, Inc., Lawrence, Kansas 66044 Copyright ¸ by the American Ornithologists'Union, 1984 ISBN: 0-943610-39-7 THE MARINE ECOLOGY OF BIRDS IN THE ROSS SEA, ANTARCTICA BY DAVID G. AINLEY, EDMUND F. O'CONNOR AND ROBERT J. BOEKELHEIDE Point Reyes Bird Observatory Stinson Beach, California ORNITHOLOGICAL MONOGRAPHS NO. 32 PUBLISHED BY THE AMERICAN ORNITHOLOGISTS' UNION WASHINGTON, D.C. 1984 TABLE OF CONTENTS LIST OF FIGURES ................................................................................................................................................................vi LIST OF TABLES ....................................................................................................................................................................viii LIST OF APPENDICES ...................................................................................................................................................ix INTRODUCTION ...................................................................................................................................................................1 METHODS ........................................................................................................................................................................................3 CENSUSES ...................................................................................................................................................................................3 POPULATION ESTIMATES .........................................................................................................................................6 FEEDING STUDIES ...........................................................................................................................................................8 ENVIRONMENT ....................................................................................................................................................................9 SPECIES DISTRIBUTIONS AND NUMBERS ..............................................................................17 EMPEROR PENGUIN ......................................................................................................................................................17 KING PENGUIN ...................................................................................................................................................................21 AD•LIE PENGUIN .............................................................................................................................................................23 ALBATROSS............................................................................................................................................................................... 29 SOUTHERN GIANT FULMAR ...............................................................................................................................32 SOUTHERN FULMAR .....................................................................................................................................................32 ANTARCTIC PETREL ......................................................................................................................................................37 CAPE PETREL .........................................................................................................................................................................38 SNOW PETREL .......................................................................................................................................................................38 ANTARCTIC PRION .........................................................................................................................................................46 BLUE PETREL ........................................................................................................................................................................46 WHITE-HEADED PETREL ............................................................................................................................................46 MOTTLED PETREL ..........................................................................................................................................................46 WHITE-CHINNED PETREL ..........................................................................................................................................49 SOOTY SHEARWATER ...................................................................................................................................................50 WILSON'S STORM-PETREL .....................................................................................................................................53 BLACK-BELLIED STORM-PETREL ......................................................................................................................53 DIVING PETREL ....................................................................................................................................................................56 BROWN SKUA ......................................................................................................................................................................56 SOUTH POLAR SKUA ....................................................................................................................................................56 ARCTIC TERN .......................................................................................................................................................................61 FEEDING BEHAVIOR ....................................................................................................................................................61 TROPHIC RELATIONS .................................................................................................................................................63 DIET COMPOSITION ......................................................................................................................................................64 DIET OVERLAP ....................................................................................................................................................................68 SYNTHESIS AND DISCUSSION .....................................................................................................................72 COMMUNITY COMPOSITION .................................................................................................................................72 FACTORS AFFECTING SEABIRD OCCURRENCE ...............................................................................76 COMMUNITY BIOMASS ...............................................................................................................................................78 TROPHIC INTERACTIONS ..........................................................................................................................................81 ACKNOWLEDGMENTS ..................................................................................................................................................86 SUMMARY ..........................................................................................................................................................................................87 LITERATURE CITED ..........................................................................................................................................................88 APPENDICES ....................................................................................................................................................................................92