Can you teach an old parrot new tricks? Individual variation in the problem-solving abilities of wild kaka (Nestor meridionalis) by Julia Loepelt A thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Doctor of Philosophy. Victoria University of Wellington Te Whare Wānanga o te Ūpoko o te Ika a Māui 2016 “It is not only fine feathers that make fine birds.” Aesop, The Jay and the Peacock This thesis was conducted under the supervision of Associate Professor Kevin C. Burns Victoria University of Wellington Wellington, New Zealand and Dr. Rachael C. Shaw Victoria University of Wellington Wellington, New Zealand ABSTRACT Identifying factors that may influence cognitive variation in the wild is essential for furthering our understanding of how ecological and evolutionary mechanisms shape cognitive phenotypes. Yet, studies on cognitive variation in the wild and its causes and consequences are still rare. In both the wild and captivity, birds have become a centre of attention, revealing striking cognitive abilities that may rival the great apes. While much of this research has focused on corvids, few parrot species have been studied thoroughly. One of these species is the kea (Nestor notabilis), which has shown remarkable social and physical cognitive skills, including the use of tools. This thesis explores the innovative problem-solving skills of the only other Nestor species, the kaka (Nestor meridionalis), with the overall aim to investigate ecological, developmental and genetic factors influencing within-species variation of these abilities in the wild. When confronted with a series of novel problems at a familiar feeding station, juvenile kaka outperform adult kaka, especially in their ability and efficiency to find an innovative solution to acquiring the food reward. This is particularly the case when modification of a pre-learned behavioural response is required and is further expressed in the juveniles’ higher individual persistence and exploration diversity, which suggests they may be more behaviourally flexible. Testing for this hypothesis using a Multi-Access-Box approach confirmed faster, more flexible discovery of alternative solving strategies in younger birds. Further analysis of the kaka’s innovation abilities uncovered potential genetic effects on solving ability as shown by full sibling comparison. This provides first potential evidence for heritability of a cognitive trait in the wild and thus presents an important step for furthering our understanding of how natural selection may act on cognitive traits. Between- species comparison of kaka and kea in the physical and social cognitive domains reveals striking similarities. This suggests that the differences in the life histories of these two species play a secondary role in the evolution of Nestor parrot cognitive abilities, which may instead be retained from their common ancestor. vii viii ACKNOWLEDGMENTS First of all, I would like to thank my supervisors, AProf Kevin C. Burns and Dr Rachael C Shaw, for the advice and support they’ve provided and their helpful comments and suggestions on my manuscripts. Many thanks also to the Zealandia Wildlife Sanctuary staff, particularly Raewyn Empson and Matu Booth for permission to conduct this research and providing records on RFID tags, age and sex of the subjects. I am additionally very grateful to Matu for his constant support, advice and for always being available. Similarly, I am immensely grateful to Judi and Linton Miller. Judi was an indispensable source of information, contacts and kaka photos. Without her efforts, I would not have had half as many excellent field assistants as I did. The most significant among them, Linton, who spent countless hours with me in the field often without a single kaka showing up. His patience was much appreciated and his skills in reading band numbers essential to many of the analyses in this thesis. Thanks to both of them also for their efforts with banding kaka nestlings. Many thanks also to all the other volunteers who assisted me in the field, Chris Gee, Lynn Freeman, Erin Dredaldry, Brony Shepherd, Bill Beale, Adam Glover, Anne Jackson, Leila Rauzi, Audrey Scott, Emma Rowell, Franziska Elmer, Stephen Salter, Philippa Larkindale and Penny Salmond. Without their help in identifying and recording kaka at the test locations, I would not have been able to investigate social learning effects. Additionally, special thanks to Audrey Scott for entering countless sheets of observational data into Excel and to Brony Shepherd for lending me her binoculars for the difficult task of reading band numbers. Many thanks also to Greg Howell and Andrew Hawke for photo contributions A huge thank you also to Lisa Woods for statistical advice and writing the R code that enabled me to analyse the mounds of data recorded by the microchip readers. Thank you to Neville Higgison for assistance with and building of test apparatuses. I would further like to acknowledge Ron Goudswaard for his assistance with the microchip readers at Zealandia and Stuart Cockburn at the Department of Conservation for providing me with an updated version of the downloading software for the dataloggers. ix Many thanks also to Peter Dilks at the Department of Conservation for providing me with much needed kaka bands and to the Kakapo recovery team for allowing me to test Sirocco in a comparative setting. I am also very grateful to Jason Low for his advice and supervision at the start of my study and Andrew Digby for sharing his experience and knowledge with sound recording gear and analysis. Thank you to Kirsty Yule for interesting discussions and insight into her research on the tri-trophic interactions between kaka, the wood-boring Pūriri moth larvae the prey on, and their host trees. Thank you to Claudia Menzel and Martin Schmelz for their helpful comments on various parts of this thesis. This research was funded by the VUW Research Trust. I am very grateful for the additional financial support through a Victoria University Doctoral Scholarship, a Victoria Doctoral Submission Scholarship, and a Faculty Strategic Research Grant. A huge thank you to my amazing friends and family, near and far, for their constant support, love and encouragement. Most importantly, Claudia Menzel, thank you for always being there, for skype calls lasting four hours and for just getting me. Thank you to Martin Schmelz and Fabian Westermann for always listening. Thank you to Meghan Cooling and Oliver Quinn for sharing the pain. And I am also very grateful to Jim and Eve McMahon for providing me with a home during my first months in New Zealand and continuing to share in this experience. Finally, thanks to all my feathered friends for their eager participation in my research, for always making me laugh and keeping me sane. x STATEMENT OF AUTHORSHIP I hereby confirm that this thesis is my own work and that all sources quoted, paraphrased or otherwise referred to have been properly acknowledged in the references. I confirm that this thesis has not been previously submitted for the award of a degree by this or any other university. Any parts of this thesis that resulted from the contribution of others are detailed below or in the Acknowledgements. Chapters 2 to 4 were written as independent manuscripts intended for publication. As these chapters included contributions of collaborators, they were written in first person plural tense. I am the primary author of each of these papers, with my supervisors, AProf Kevin C. Burns and Dr Rachael C Shaw, as co-authors. Chapters submitted for publication are reproduced in published form in the style of the journal, but with minor modifications to the formatting, and with added cross-references between chapters. As a collection of papers, there is unavoidably some repetition between chapters, particularly in the introductions. Any results which could not be included in manuscripts due to constraints of time or space are included in appendices at the end of the thesis. In all instances, I designed the studies, carried out the field work and data collection, and drafted the manuscripts. My supervisors provided advice throughout and contributed to study designs, data analyses and the editing of the manuscripts. Chapter 2 was published in Proceedings of the Royal Society B: Biological Sciences 283:20153056 on June 1st 2016 under the titel “Can you teach an old parrot new tricks? Cognitive development in wild kaka (Nestor meridionalis)”. The research presented here was approved by the Victoria University of Wellington Animal Ethics Committee (Application no. 2013R20) and the Karori Sanctuary Trust. xi xii TABLE OF CONTENTS Abstract .............................................................................................................................. vii Acknowledgments............................................................................................................... ix Statement of Authorship ..................................................................................................... xi Table of Contents ............................................................................................................. xiii List of Figures ................................................................................................................... xvi List of Tables ..................................................................................................................... xx 1 General Introduction ...................................................................................................