IN SOUTHERN TASMANIA

Transcription

1 SOME ASPECTS OF THE ECOLOGY OF THE FAIRY PENGUIN EUDYFTULA - MINOR NOVAMOLL~DIAE (FORSTER IN SOUTHERN TASMANIA Volume I by ANN HODGSON B. Sc. Hons. (Tas. ) (nie PHILLIPS) kubnitted in fulfilment of the requirements for the degree of Doctor of philosophy UNIVERSITY OF TASYANIA HOBART June,

2 Except as stated therein, this thesis contains no material which has been accepted for the award of any other degree or diploma in aqy university, and to the best of ny knowledge and belief, this ' thesis contains no copy or paraphrase of material previously published or written by another person, except when due reference is made in the t& of the thesis. Ann Ho&son

3 FRONTISPIECE

4 (iii ) I would like to thank the Higher Degrees Committee of the University of Tasmania Faculty of Science for allowing me to defer the writing of this thesis until qy children both attained school age. It is a pleasure to convey my appreciation to Er. w.5 Bryden, former Director of the Tasmanian fiseum,for suggesting the topic and for his keen interest and active encouragement during the early years of intensive study. thanks are also due to the Trustees of the Tasmanian Muaeum for making it possible for me to carry out field work in 1959, and I am grateful for the financial assistance provided by a Commonwealth Postgraduate Studentship in '1961 and For valuable advice and encouragement and-for criticism and....,. discussion of the draft manuscript, I am indebted to'n'fsupervisors,.... >::,....'. 1 i." Professor B. Johnson and Dr..E.R. Guiler of the Unive+s%ty of Tasmania... Zoology Department. I am also grateful to heritus Professor V.V. Hiclanan and Professor M. Clark (both formerly of the University of Tasmania Zoology Department) and to Dr. J.L. Hickman of the Zoology Department for guidance and helpful discussions. For assistance in identifying elements of the flora, nw thanks are due to Professor W.D. Jackson of the Botany Department. I would like to express to Drs. C.B. Hallam of the Tasmanian College of Advanced Education Mathematics Department, I.S. Wilson and J.E. University of Tasmania Zoology and Physics Departments, Humble of the appreciation of their interest and my thanks for advice and assistance with statistical procedures. For technical assistance, my thanks are due to Mr. R.G. Wheeldon

5 and other members of the technical staffs of the unijersity of Tasnania Zoology, Botany and Physics Departments and Central Workshop, also to Mr. D. Alexander (formerly of the Tasmanian hseum). Appreciation is due to Mr. H. Harvey, Mr. A. Beswick and the staff of the University of Tasmania Photographic Section; and the State Government Lands Department (for advice, photographic assistance and supplying aerial survey photographs); to Mr. P. Ryan B.V. Sc. (formerly of the State Government Agricultural Department) who carried out several post mortems; to Mr. D. Purchase of the C.S.I.R.O. Division of Wildlife Research, Messrs. K.R. Ayers, H. Battam, D.G.W. Hollands, S.G. Lane and M.T. Templeton and to the Tamian Animals and Birds Protection Board (for permission to refer to information concerning recoveries of penguins). I am grateful to Mr. F.C. Kinsky for providing a sample band for copying and for his continuing interest in this project, also to Mrs. P. ~eiil~, who allowed me to consult some of her unpublished work. I am deeply indebted to Mrs. M.O. Carter for the time she has spent and for her patience and care in typing draft and final copies of the extensive tables in the Appendix; to Mrs. J. Strong for her excellent secretarial help in typing the remaining tables and the manuscript. I am also grateful to Mrs. Joan Humble for tracing a difficult diagram. Finally, I would like to thank qy husband, Bill, for his forbearance and encouragement, for assistance in tracing drawings and for proof reading. I also greatly appreciate the help given by my father in reliev5ng me of many domestic responsibilities.

6 Page SUMMARY SETION 1 GENERAL INTRODUCTION 1.0 INTRODUCTION 1.1 AIMS 1.2 SYNONYMP 1.3 HISTORICAL REVIEW AND DISTRIBUTION viii 1 SECTION 2 DEFINITIONS AND EX+LANATIONS OF TERMS USED 2.0 KEY TO ABBREVIATIONS USED IN TABLES AND FIGURES 2.1 SITES 2.2 CATEGORIES OF BIRDS 2 3 STAGES OF THE ANNUAL CYCLE 2.b MATING AND BREEDING BMAVIOUR 2.5 CALLS, DISPIAYS, FIGRTING AND MISCELLANM)US BMAVIOUR SECTION 3 MATEEIALS AND METHODS 3.0 INTRODUCTION 3.1 MARKING OF NESTING, ROOSTING AND MOULTING PLACES 3.2 MARKING OF ADULTS AND FLEDGLINGS 3.3 MARKING OF EGGS AND CHICKS 3.b EQUIPrn 3.5 INTENSIVE STUDY AREA 3.6 SUBSIDIARY STUDY AREAS 3.7 VISITS TO STUDY AREAS AND COLLECTION OF DATA 3.8 EVIDENCE OF HUMAN MPEEFERrnCE

7 Page SECTION 4 WEIGIFP CYCLES 58 L. 0 ITJTRODUCT ION MEAN WEIGHTS OF BREEDING BIRDS 60 L. 2 I~IVIDUAL WEIGHTS OF BREEDING BIRDS DAILY LOSS OF WEIGHT OF MOULTING BIRDS 4.4 WEIGHTS OF NCRMAL SUCCESSFUI CHICKS 4.5 WEIGWS OF CHICKS FED BY FOSTFEi PARENTS SECTION DISCUSSION AM1 CONCLUSIONS MEASUREMENTS AND SEX RECOGNlTION 5.0 INTRODUCTION 5.1 PROCEDURES USED FOR MEASURING DISSECTED ZECIMENS AND LIVE BIRDS 5.2 MFASUREMENPS OF BREEDING BIRDS 5.3 SEX RECOGNITION OF ADULT BIRDS 5. b MEASUREMENTS OF CHICKS, JUVENILES AND YOUNG ADULTS 5.5 SEX RATIOS 5.6 DISCUSSION AND CONCLUSIONS SECTION 6 DISF'ERSAL, RETURNS, RECOGNITION OF YOUNG BIRDS AM) LONGEVITY 6.0 INTFtODUCT ION NUMBERS AND MCATIONS OF BIRDS BANDED RECOVERIES OF BIRDS AWAY FROM THE STUDY AREAS RETURNS OF BIRDS BANDED AS FLEDGLINGS AND 176 RECOGNITION OF JUVENILES AND YOUNG ADULTS 6.L REPURNS OF ADULTS AND LONGEVITY 2 Oh 6.5 DISCUSSION AND CONCLUSIONS 208

8 (vii ) SECTION 7 SECTION 8 SECTION 9 REFERENCES THE ANNUAL CYCLE IN SOUTHERN TASMANIA 7.0 INTRODUCTION 7.1 WINTrn PERIOD 7.2 PRE-EGG PERIOD 7.3 PAIR BOND AND NEST RETWION 7.4 EGG-LAYING 7.5 INCUBAT ION 7.6 CHICK PERIOD 7.7 POST-BREEDING PFRIOD AND MOULT 7.8 DISCUSSION AND CONCLUSIONS THE PENGUIN COMMUNITY AT THE NECK STUDY AREA 8.0 INTRODUCTION 8.1 CASUAL VISITORS 8.2 EAST/WESP POPULATIONS AND LOCAL GROUPS 8.3 BREEDING FAILURES AND SUCCESSES OF EAST AND hts! POPULATIONS 8.4 ESTIMATIONS OF THE TOTAL POPULATION AT THE NECK STUDY AREA 8.5 DISCUSSION AND CONCLUSIONS GENERAL DISCUSSION AND CONCLUSIONS 9.1 DISCUSSION 9.2 CONCLUSIONS Page PLATES I - XVI LIFT-OIPT KEY (in back Pocket) VOLUME I1 APPENDICES

9 SUMMARY Observations of the fairy penguin commenced in 1958 and are continuing intermittently at three sites in Southern Tasmania. Graphs and tables of kghts were useful in interpreting the behaviour of breeding birds. Departure weights of fledglings were used as criteria for breeding success. Birds were sexed by cloaca1 examination, confirmed by dissection when possible. Provisional sexing by accurate measurements and comparisons of bill depths proved 97% reliable with adults and was applied to fledglings. Between 1959 and 1963 at the intensive study area on the Neck connecting North and South Bruny Island, a surplus of females, not evident among fledglings, adversely affected the breeding of many birds. Juveniles displayed, kept company and occupied nests without breeding. TWO- and three-year-old birds bred unsuccessfully. Young birds not banded as fledglings were detected by bill size or growth and irregularities in behaviour causing breeding failure. Recoveries from Victoria, Cape Barren Island and South Australia of birds banded as fledglings or suspected juveniles, included one which had bred unsuccessfully seven years earlier on Bruqy Island. Four males and eleven females, returning here when over ten years old, included two females which were established breeders thirteen years earlier and therefore aged at least sixteen years. From May to July the few birds that came ashore collected nesting material, displayed and copulated promiscuously, often in the open. From August onwards displays increased in intensity prior to egg-laying, both sexes participating in fighting and nests being

10 occupied by successive pairs with frequent exchanges of partners. Eggs were laid from September to December and daily observations were essential to determine the birds responsible. Clutches of two eggs were produced within h5 to 96 hours. Most eggs laid late in the season and all second clutches were unsuccessful. No second clutch was produced following breeding success. Successful parents alternated in incubating eggs for 31.5 to 38.5 days and in guarding chicks for a further 16 to 28 days, then combined to feed them regularly until they departed. Chick mortality was high at 77%. Males delivered more food, but deserted more readily. Feathering necessitated abundant food, shortage causing immediate retardation. The critical period was after banding, when chicks were over 5 to 6 weeks old. Rare cases of adoption of a young chick and feeding of alien fledglings were recorded. Onset of breeding and moulting were correlated. Irrespective of condition, moulting could not be unduly delayed. The process took 15 to 20 days. Breeding pairs often moulted together. Small groups of separate east and west populations occupied different localities on the east and west sidesof the Neck study area, with some overlapping and a few east-west matings. The total population gradually declined, due to natural losses, mainly from the pod-chick to the pre-egg period and losses of breeding and non-breeding birds attributable to human agency. The resulting disturbances affected breeding in subsequent seasons and few young west side birds became established, so that by 1972 the west population was nearly non-existent.