CHARLES STURT UNIVERSITY Competitive behaviour in Common Mynas An investigation into potential impacts on native fauna and solutions for management Kathryn Haythorpe B.A. B.Sc. B.Env.Sc.Mgt.(Hons) August 2013 Common Mynas and an Eastern Rosella at a nest box. Photo: K. Haythorpe. Thesis submitted to Charles Sturt University in partial fulfilment of the requirements of the Doctor of Philosophy (PhD) Table of Contents Table of Contents ................................................................................................................ 1 Certificate of Authorship ..................................................................................................... 3 Acknowledgements ............................................................................................................. 5 Ethics Statement .................................................................................................................. 7 Abstract ............................................................................................................................... 9 Introduction ....................................................................................................................... 11 Introduced Species .................................................................................................... 11 The Science of Invasion ........................................................................................ 11 The Problem of Introduced Species ...................................................................... 12 Potential Bias in the Study of Invasion Science .................................................... 13 Introduced Birds .................................................................................................... 14 Common Mynas ........................................................................................................ 16 Origin and introduction to Australia ..................................................................... 16 Distribution and habitat ........................................................................................ 18 Feeding .................................................................................................................. 18 Reproduction ......................................................................................................... 19 Management and control ...................................................................................... 20 Are Common Mynas having an Impact on Native Species? ..................................... 22 Aggression and Competition with Native Species ................................................ 22 Nest Predation ....................................................................................................... 23 Evidence for Impact on Wildlife ............................................................................ 24 1 Public Opinion ...................................................................................................... 26 Preface ....................................................................................................................... 29 Aims .......................................................................................................................... 31 References ................................................................................................................. 32 Chapter 1: Relative levels of food aggression displayed by Common Mynas when foraging with other bird species in suburbia .................................................................................... 41 Chapter 2: The native versus alien dichotomy: Relative impact of native noisy miners and introduced common mynas ............................................................................................... 65 Chapter 3: Nesting behaviour in Common Mynas Sturnus tristis in an urban environment, and potential effects on competing rosella species. ........................................................... 93 Chapter 4: The use of nest boxes in suburban backyards: homeowner perspectives ...... 133 Conclusions ..................................................................................................................... 155 Specific contributions .............................................................................................. 155 Limitations and future directions ............................................................................ 158 Appendix A: PhD publications ........................................................................................ 163 Appendix B: Non-PhD publications ................................................................................ 189 Appendix C: Media ......................................................................................................... 207 2 Certificate of Authorship I hereby declare that this submission is my own work and that, to the best of my knowledge and belief, it contains no material previously published or written by another person nor material which to a substantial extent has been accepted for the award of any other degree or diploma at Charles Sturt University or any other educational institution, except where due acknowledgment is made in the thesis. Any contribution made to the research by colleagues with whom I have worked at Charles Sturt University or elsewhere during my candidature is fully acknowledged. I agree that this thesis be accessible for the purpose of study and research in accordance with the normal conditions established by the Executive Director, Library Services or nominee, for the care, loan and reproduction of theses. Kathryn M. Haythorpe January 2014 3 4 Acknowledgements Where do I begin? This project could not have come together without the help of so many people. To all the people below, and probably many more, I owe my sincere thanks. To my supervisors Darren Burke and Danielle Sulikowski, who helped me when I needed it the most. For all you have done for me and all the times you continued to believe in me, I am forever in your debt. Thanks also to Michael Kiernan who came on board as a supervisor for the last part of the journey at CSU, and always had a word of encouragement for me. Thanks to Nicholas Harris, Kathryn Anderson, and Marie Diquelou, for your support, humour and friendship, and endless assistance with ideas, drafts, analysis, and generally coping with being a PhD student. Kate Grarock of the Great Nest Box Project at Australian National University and Bill Handke of the Canberra Indian Myna Action Group were instrumental in bringing about the nest box portion of this PhD and I am very grateful for their support. Simon Griffith of Macquarie University also provided a key role in earlier discussions of this topic. I thank also Daniel Atkins and Andrew Howells for providing me with their outstanding drawings of nest boxes and Common Mynas. This work would not have been possible without funding in the form of grants and scholarships from the Tom Farrell Institute, Port Stephens Council, Lake Macquarie City Council, Newcastle University, and Charles Sturt University. All the volunteers who assisted with field work also contributed greatly to this project, and my thanks go to these people – Terry Bignell, Grace Bourke, Joseph Brennan, Amanda Lilleyman, Jason Lowe, Stephen Marsh, and Stephanie Van Dijk. My thanks go to the residents of Canberra who were kind enough to host nest boxes, and in some cases also cameras, for this project. I am also grateful to 5 the numerous respondents to my survey who provided me with their insights and opinions. Finally, my thanks go to my family – my mum Trixie, dad Vic, and brother Michael, who have always encouraged me to be the best I can be and loved me through thick and thin. You mean the world to me. 6 Ethics Statement This work was carried out under the following ethics protocols: Chapter 1: Newcastle University Animal Ethics Committee ethics protocol A-2008-173 Chapter 2: Newcastle University Animal Ethics Committee ethics protocol A-2008-173 Newcastle University Animal Ethics Committee ethics protocol A-2011-103 Chapter 3: Newcastle University Animal Ethics Committee ethics protocol A-2011-103 Charles Sturt University Animal Care and Ethics Committee ethics protocol 11/074 Chapter 4: Newcastle University Human Ethics Committee ethics protocol H-2011-0217 7 8 Abstract The introduction of organisms to new areas is a source of ongoing concern for environmental managers. Common Mynas Sturnus tristis are an introduced bird species found along the East coast of Australia that are thought to aggressively outcompete native species for food and nesting resources. Public attitudes towards Common Mynas are extremely negative, and substantial time and financial resources are allocated towards control and eradication of the species. However, most accounts of aggression from Common Mynas are anecdotal, and empirical evidence of a significant impact on native species in Australia due to the presence of Common Mynas is yet to be found. In this thesis I examined the competitive behaviour of Common Mynas around food and nesting resources to quantify this impact. I found that, contrary to all expectations, Common Mynas were one of the least aggressive species studied. Some native species like Noisy Miners Manorina melanocephala and Australian Magpies Cracticus tibicen display much higher levels of aggression and have the potential to be far more detrimental to native species, yet are not subject