SCIENTIA MANU E T MENTE ANALYSIS OF RECOVERY-RECAPTURE DATA FOR LITTLE PENGUINS A thesis submitted for the degree of Doctor of Philosophy By Leesa A. Sidhu School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, Australian Defence Force Academy. November 2007 ORIGINALITY STATEMENT 'I hereby declare that this submission is my own work and to the best of my knowledge it contains no materials previously published or written by another person, or substantial proportions of material which have been accepted for the award of any other degree or diploma at UNSW or any other educational institution, except where due acknowledge- ment is made in the thesis. Any contribution made to the research by others, with whom I have worked at UNSW or elsewhere, is explicitly acknowledged in the thesis. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistancefrom others in the project's designand conceptionor in style, presentation and linguistic expression is acknowledged.' Signed... x.'as,a Date r /t /: e?7 COPYRIGHT STATEMENT 'I hereby grant the UNSW or its agents the right to archive and to make available my thesis or dissertation in whole or part in the University libraries in all forms of media, now or here after known, subject to the provisions of the Copyright Act 1968. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. I also authorise University Microfilms to use the three hundred and fifby word abstract of my thesis in Dissertation Abstract International (this is applicable to doctoral thesesonly). I have either used no substantial portions of copyright material in my thesis or I have obtained permission to use copyright material; where permission has not been granted I have applied/will apply for a partial restriction of the digital copy of my thesis or dissertation'' signed. ../ A.-f(& Date ?/ u /aa7 z ll AUTHENTICITY STATEMENT 'I certify that the Library deposit digital copy is a direct equivalent of the final officially approvedversion of my thesis. No emendationof contenthas occurred and if there are any minor variationsin formatting, they are the result of the conversionto digital format.' signed...../.Atk Date 7fur/aa.a.7. ltl Abstract This thesis analyses yearly mark-recapture-recovery information collected over a 36- year period, from 1968 to 2003, for 23686 flipper-banded Little Penguins Eudyptula minor of Phillip Island, in south-eastern Australia. Such a long-term data set is extremely rare for any species. Few studies of any animal have been able to model age dependence for the sur- vival, recapture and recovery probabilities simultaneously. I successfully apply such a modelling scheme and obtain biologically realistic age structures for the parame- ters. I also provide illustrations of erroneous results that may arise when analyses fail to consider simultaneous age dependence, or fail to detect annual variations that may mask age dependence. I obtain a low survival estimate of 17% in the first year of life, increasing to 71% in the second year, and around 80% thereafter, and declining gradually after age nine years. First-year survival increases with number of chicks fledged per pair, increases with annual average fledging weight and decreases with mean laying date. An in- crease in first-year survival is associated with warmer sea surface temperatures in the summer and autumn of the previous year, which agrees with biological consid- erations. Irrespective of this inter-year variation, birds born early in the breeding season, relative to the rest of their cohort, have greatly enhanced first-year survival, when compared to birds born late in that season. Fledglings survive better in years in which the mean fledgling weight is higher, and fledglings of above average weight have a better chance of survival than their underweight counterparts. I next analyse seven years of recapture data from a separate experiment studying the effect of banding on adult Little Penguins. In the year following marking, the i survival probability of banded birds is 6% lower than that of unbanded birds, while in subsequent years the survival is 4% lower for banded birds. Band loss is negligible. Finally, I compare the survival estimates for Phillip Island with those obtained for a six-year study in New Zealand. While first-year survival is significantly higher for New Zealand, there is a marked decline over time, coinciding with an increase in population size. ii Acknowledgements I wish to acknowledge my supervisors: Ted Catchpole from UNSW at ADFA, and Peter Dann from the Research Group at the Phillip Island Nature Park. I owe an enormous debt to my long-suffering supervisor, Ted Catchpole, who has continued to provide “full-time” supervision since his retirement in September 2004. I have greatly appreciated the way in which Ted has always been willing to offer his expert assistance at any time and on any topic — from statistical queries to LaTeX, to programming in Matlab or R, and so on. I have learned an enormous amount from Ted, and he has been a wonderful role model as a researcher. His kindness and his incredible enthusiasm for all of my achievements have been much appreciated. My PhD project has been greatly enhanced by the input of my co-supervisor, Peter Dann. I began this project with no biological background, and I have been very fortunate to be able to access Peter’s expert biological advice. On numerous occasions, I have sent Peter emails of questions that sometimes require him to retrieve the hand-written data from the early 1970s! I am grateful to Peter for patiently answering my endless questions about Little Penguins and the data, and for his good-humoured advice and continual encouragement throughout this project. I wish to thank Mark Collins for taking on the role of joint supervisor from September 2004 until he left ADFA in July 2006. Mark’s enthusiasm for my work and his continual encouragement and support have been much appreciated. I thank my husband, Harvinder, for always believing in me, and for his encour- agement and advice in helping to get me back on track on the odd occasion when I became slightly de-railed! I greatly appreciate the years he has spent juggling his own work and our children, Kurran and Dhiaan. His efforts have enabled me to complete this thesis. iii I am grateful to my parents, Jim and Judy McEwan, for the unconditional love and support that they have always given me, and for their numerous car trips from Ipswich to Canberra to help look after the children, so that I could work on my thesis. Those four week trips have been invaluable. I also wish to thank my parents-in-law, Karam Singh and Sukhdev Kaur, for travelling from Singapore to help out with child care and home duties, and giving me time to work on my thesis. I am indebted to staff of the Phillip Island Nature Park, particularly Ros Jessop, Marg Healy and Leanne Renwick, and to members of the Penguin Study Group and the Australian Bird and Bat Banding Scheme for providing the data upon which this study is based. I also wish to acknowledge Lynda Chambers (from the Australian Bureau of Meteorology) for providing sea surface temperature data and Figure 1.1, and Dave Houston who provided the data from Oamaru, New Zealand. I am grateful to Edda Johannesen for suggesting that we compare the survival of Little Penguins in Australia and New Zealand, and for providing valuable input into Chapter 8. I am grateful to my examiners for their careful appraisal of this thesis. Their insightful comments and suggestions were very valuable. This work was conducted under the support of an Australian Postgraduate Award, and using the resources of the School of Mathematics and Statistics and later the School of Physical, Environmental and Mathematical Sciences (PEMS) at UNSW @ ADFA. I wish to thank my colleagues in the School of PEMS for their friendship and encouragement throughout my thesis. I am also grateful to Anthony Tate and other members of the computing staff for sorting out those inevitable computer problems, to Annabelle Boag and David Paull for their assistance with some of the Figures, and to the mathematics and statistics staff for allowing me to do some intense “number crunching” on their machines after hours. I wish to acknowledge Professor J.M. (Mike) Cullen who worked with the pen- guin research group on Phillip Island for 25 years, up until his death in March 2001. My PhD project came into being when Mike sent the penguin data to Ted, slightly before I came to ADFA as an Associate Lecturer in 1997. Mike’s keen mind, incred- ible insight, endless hypothesizing and boundless enthusiasm for any result I sent him, no matter how seemingly insignificant, were inspirational. Years later, I have iv obtained results of biological interest and commented to Ted, “That’s just the way Mike thought it would be!” Maximum likelihood fitting was performed via the MATLAB package, under the GNU-Linux operating system. It is not commonly known that the Linux mascot, “Tux”, is a Little Penguin, chosen by Linus Torvalds (the author of Linux) during a visit to the National Zoo and Aquarium in Canberra. v Contents Abstract i Acknowledgements iii Chapter 1 Introduction 1 1.1 BackgroundofStudy .......................... 1 1.1.1 TheStudySites......................... 2 1.1.2 TheDataCollection ...................... 4 1.2 Rationaleforstudy ........................... 5 1.3 Thesisoverview ............................. 6 1.4 Publications arising from the thesis and in preparation ......