University of Wollongong Research Online University of Wollongong Thesis Collection University of Wollongong Thesis Collections 2011 Variation in the health of tropical finches in relation to conservation status, season and land tenure Kimberly Lynn Maute University of Wollongong, [email protected] Recommended Citation Maute, Kimberly Lynn, Variation in the health of tropical finches in relation to conservation status, season and land tenure, Doctor of Philosophy thesis, Department of Biological Sciences, Faculty of Science, University of Wollongong, 2011. http://ro.uow.edu.au/ theses/3390 Research Online is the open access institutional repository for the University of Wollongong. For further information contact Manager Repository Services: [email protected]. Variation in the health of tropical finches in relation to conservation status, season and land tenure A thesis submitted in fulfilment of the requirements for the award of the degree Doctor of Philosophy from University of Wollongong by Kimberly Lynn Maute, BSc (Hons) Department of Biological Sciences 2011 i Thesis Certification I, Kimberly Lynn Maute, declare that this thesis, submitted in fulfilment of the requirements for the award of Doctor of Philosophy, in the Department of Biological Sciences, University of Wollongong, is wholly my own work unless otherwise referenced or acknowledged. The document has not been submitted for qualifications at any other academic institution. The data chapters (2 – 5) have been written and formatted for submission to academic journals. The role of potential co-authors in these chapters has been strictly supervisory. This thesis does not contain data that was substantially collected and analyzed by anyone other than myself. Kimberly Lynn Maute 22 March 2011 ii Acknowledgements I thank my supervisors, Sarah Legge (Australian Wildlife Conservancy), Lee Astheimer and William Buttemer (Deakin University), Kris French and Jack Baker (University of Wollongong) for helping me to take advantage of the opportunity to complete a PhD project. Their advice was indispensable in the completion of this research and the writing of my thesis. William Buttemer blind tested several of my finch plasma samples for osmolality, assisting in the validation of my assumptions that birds were not dehydrated (Chapter 1). Stephen Murphy and Douglas Schaefer, while working for the Australian Wildlife Conservancy, sexed several of my bird blood samples. Numerous AWC staff at the Mornington Wildlife Sanctuary were kind enough to look after key field gear and red-blood samples while I was in the laboratory in Wollongong. I thank them for their caretaking. Lee Astheimer, Amanda Guy and Colin Cortie organized my laboratory space and trained me in the basics of laboratory work, giving me the background I needed to perform and troubleshoot stress hormone (Corticosterone (CORT) and Corticosterone-binding- globulin (CBG)) assays using bird plasma. I thank the many people who went to great lengths to ensure I was given access to funds, equipment, and study sites. I thank the Kowanyama and Pormpuraaw Community Councils for the privilege of visiting their land and studying their wildlife, as well as the key people in the Lands offices who helped initiate contact (Viv Sinnamon, Arvid, Kath, Colin and Rangers in Kowanyama; Rob Morris, John Clark and Rangers in Pormpuraaw). The Jawoyn Association was also kind iii enough to allow me to study birds on their traditional lands in the Yinberri Hills, NT. I would like to thank Mick Peirce and Ian McConnell for liaising with me for access to Jawoyn land. Vista Gold Mining also assisted with access to the Yinberri Hills area. I thank Brad Bell, Robbie Friel and the mine staff for their help and patience with my requests for access at such early hours of the morning. I thank the Department of Defence officials who provided me access to Bradshaw Field Training Area and helped me locate finches and waterholes (Kylie Browne, Range Control Officers Sargent Pop Dawes, John McCrystal, Peter Watts, and the wonderful caretakers Peter and Jenny from Wildman). I would have been a bit lost without the help of countless QPWS and NT rangers and staff who guided me through the country and helped find me shelter (Andrew Hartwig and Steve Anderson in QLD, Anne Walters, David Hooper, and Edith Falls Rangers in the NT). The warm hospitality of pastoralists Shane Johnstone, James and Jenel, Mark and Linda, Tom and Sue Shephard, and Don and Wendy was gratefully appreciated. Mark and Linda from Delamere were immensely helpful in providing me advice and support. My field work was made so much more pleasant by the amazing birders and researchers who helped us find finches (Michael Todd, Sue and Gary at Lotus Bird Lodge). I thank the Black-throated Finch Recovery Team and friends (Jo Wieneke, Tony Grice, Bill Holmes, Rosemary Payet, Marnie McCullough) for keeping me informed of finch movements near Townsville. In particular, the Venables family were an invaluable source of moral and physical encouragement. I thoroughly enjoyed the company and support of so many remarkable individuals, organizations and communities. iv Funding for this project was supported though a Linkage grant from the Australian Research Council (ARC), the Australian Wildlife Conservancy (AWC), and the NT Research and Innovation Board. I also thank Birds Australia, who generously awarded me three years of funding through the Stuart Leslie Bird Research award (2007 and 2009) and Professor Allen Keast Award (2008). Other partners included NT Parks and Wildlife, and Charles Darwin University (CDU) who both provided in- kind support. Dr. Stephen Garnett and CDU staff helped with field equipment maintenance and storage and I thank them for the time and effort required to administer the ARC Linkage Grant to my project and others affiliated with AWC. I could not have survived my field seasons without all of the help and fun company of my friends and field assistants; Emily Haber, Jill Gautreaux and the ever-positive force of Jessica Griffiths! I would not have finished this thesis without the moral support of my friends and family. I cannot thank my mother, sister, and father, James, Jacob, Karen and Olya enough for the endless hours of comforting words and advice that have helped me through this important process. v Abstract Despite the fact that Australia’s savanna is still a highly connected landscape dominated by native vegetation, over a quarter of Australia’s granivorous birds have declined in abundance or experienced range contractions over the last fifty years. It is widely assumed that cattle grazing and changed fire regimes have lowered the quality of savanna habitats for grass-seed eating species by lowering the productivity of important grasses. However, the relative impacts of changed land use on granivores such as finches remains poorly defined because of difficulties in monitoring the abundance of these semi-nomadic birds in remote areas. Consequently, my study compares the health measures of finch populations to determine if the timing and severity of changes in health indicators coincide with differing land management. The relative number of unhealthy animals can indicate a population’s probability of decline, as sick or chronically stressed individuals are less likely to survive and breed. I monitored a variety of finch species in order to describe relative granivore responses to land management. Declining species are characterized by specialized diets, prolonged breeding seasons and strictly timed moulting periods, while non-declining species have opportunistic feeding, breeding and moult strategies which could aid them in responding to the seasonal savanna environment and recent habitat changes in Northern Australia. This led me to hypothesize that health patterns would differ between these species seasonally. Therefore I monitored finches during the peak breeding season, when food vi resources are plentiful just after the wet growing season, and again in the non- breeding season, when grass seeds become scarce, and most finches are moulting. Based on the theory that grazing and burning lowers the quality of finch habitat, I also hypothesized that finches would show differences in health between populations living in areas of differing land management. Finches were monitored for two years in three study areas in the Northern Territory and three in Queensland; one site per state was conservation managed (without grazing and fire), one was pastoral (grazed but without fire), and one was aboriginal (with frequent burning, but without high grazing). The health of declining Gouldian finches and non-declining Long-tailed and Masked finches were monitored in the Northern Territory while declining Star and Black-throated finches were monitored in Queensland. Health indices included body condition measures (body mass, fat stores and muscle contour), haematocrit and stress response to capture using plasma corticosterone (CORT) and binding globulin levels. Finch habitat was surveyed in the Northern Territory in order to describe any differences in the grass layer in response to grazing or fire and among land tenures. Health monitoring results suggest that all finch species have better body condition during breeding seasons and declining species have a possible pattern of chronic stress during non-breeding seasons. All finch species had higher body mass and muscle scores and lower fat stores during breeding compared to non-breeding. Measures of CORT showed that Gouldian, Star,