The Australian White Ibis John Martin University of Wollongong

University of Wollongong Research Online University of Wollongong Thesis Collection University of Wollongong Thesis Collections 2012 Investigations into the ecology and management of a nuisance native bird in urban environments: the Australian white ibis John Martin University of Wollongong Recommended Citation Martin, John, Investigations into the ecology and management of a nuisance native bird in urban environments: the Australian white ibis, Doctor of Philosophy thesis, School of of Biological Sciences, University of Wollongong, 2012. http://ro.uow.edu.au/theses/ 3845 Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] Investigations into the ecology and management of a nuisance native bird in urban environments: the Australian white ibis A thesis submitted in fulfilment of the requirements for the award of the degree Doctor of Philosophy from UNIVERSITY OF WOLLONGONG By John Martin Bachelor of Science (Environmental) Department of Biological Sciences 2012 ii Thesis Certification I, John Martin, 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. This study was carried out with the permission of various land managers including the Centennial Park and Moore Park Trust, Bankstown City Council, Fairfield City Council, and Waste Services New South Wales. Birds were banded under approvals from Nsw South Wales National Parks and Wildlife Services (no. S12568), the Australian Bird and Bat Banding Scheme (no. 1209), and the University of Wollongong Animal Ethics Committee (no. AE05- 15r08). Each chapter is presented as a stand alone publication; consequently there is some overlap in the material presented. John Martin Date 14/09/2012 iii Abstract Urbanisation is a major global trend that presents a novel environment for wildlife to colonise. This novel environment offers an abundance of anthropogenic resources (food, water, habitat), which has occasionally resulted in wildlife encroaching upon humans. Human–wildlife conflicts may be the result of increases in wildlife populations or encroachment on human assets (e.g. dwellings, infrastructure, flight paths); the Australian white ibis (Threskiornis molucca ) is culpable in both instances. Ibis in urban settings are commonly considered a nuisance and have been lethally managed for over 20 years. There is a paucity of information, however, regarding the ecology of ibis in the natural or urban environment, and the effectiveness and consequences of the lethal management actions. To address this information gap I aimed to investigate key attributes concerning ibis behaviour to inform their management and conservation. In urban areas ibis commonly nest within close proximity to humans and are consequently viewed as a pest. Actions to deter nesting include the destruction of nests and eggs or the removal of nesting habitat (i.e. vegetation). These actions are also implemented within some of the larger breeding colonies to reduce the overall reproductive success. At the larger colonies, actions to reduce the reproductive success are conducted to appease residents under the guise that it will slow the growth of the urban population, which is viewed as an issue. These management actions can result in colony displacement, which from a regional management perspective is an undesirable outcome at the larger colonies. Consequently, I assessed a iv population control technique involving the application of vegetable oil as a method to prevent eggs hatching whilst not destroying the nest and leaving the unviable eggs to be incubated. This method resulted in reduced reproductive success whilst not causing the breeding birds to abandon their nests or the colony. To address a gap in knowledge about the size of the ibis population in urban areas, I conducted monthly population surveys of the Sydney region over the three years and confirmed that the ibis population varied annually and seasonally. The peak population of 8900 ibis was associated with the peak in the breeding season. Following the breeding season, adult and juvenile ibis were observed to disperse within and outside the Sydney region, with the population dropping to 3000. On average 40% of the ibis population was located within landfills each month, which are a major anthropogenic foraging resource. While the location of ibis within the Sydney region had been identified through the regional population surveys, the daily movement behaviour of ibis had not been assessed. To address this I fitted radio transmitters (n = 82) to ibis at an urban park, a breeding colony and a landfill foraging site to assess the foraging preferences, roost fidelity and the distance ibis travelled during daily foraging movements. Ibis were recorded moving up to 72 km from their roost during a day’s foraging at multiple locations. Landfills were identified as a major foraging resource with 63% (n = 82) of birds located therein. Ibis were located at up to nine foraging and seven roost sites indicating the v connectedness of the regional population. Lastly, the site-fidelity of adult ibis was assessed within an urban park that provides both breeding and foraging opportunities. The first year resighting rate for females was 89% (n = 59) and 76% for males (n = 34); this decreased to 41% of females and 21% of males in the fourth year. Over the four years 77% of females and 70% of males were resighted at additional sites within the study region (~50 km). Females showed greater site-fidelity than males in each of the four survey years suggesting there are greater selective pressures on males to find breeding opportunities. The results of my research indicate that the management of ibis within urban areas requires a three-pronged focus: 1. reducing access to foraging resources across the focal region, particularly management of landfill sites, 2. establishing refuge colonies where breeding can occur undisturbed, and 3. management of undesirable colonies. Implementing these actions should reduce the frequency of human–wildlife conflicts without negatively impacting the species reproductive success, specifically as the non-urban ibis population has declined in association with natural habitats over the last 30 years. vi Acknowledgements Funding for this project came from Fairfield City Council, Waste Services New South Wales (NSW), the Centennial Parklands Foundation, the Australian Museum’s Postgraduate Award, the NSW Department of Environment, Climate Change and Water (DECCW) and the W.V. Scott Charitable Trust. I would like to thank the following people for assistance with access, permits and/or field work Geoff Ross and Cici Legoe of DECCW, Judy White of Waste Services NSW, Katie Cabezas of Fairfield City Council, Joan Dawes of Pestat, Helene Forsyth of Bankstown City Council, Andrew Smith of the University of Technology Sydney and Judy Harrington of Sydney Olympic Park Authority. Thank you also to the thesis reviewers. This research was conducted in accordance with the University of Wollongong Animal Care and Ethics Committee (AE05-15r8) and NPWS Scientific Licence (S12568). Lastly, it has been a pleasure to work with my supervisors Dr Richard Major and Prof. Kris French. vii Contents Author’s declaration .......................................................................................... ii Abstract ..............................................................................................................iii Acknowledgements .......................................................................................... vi Contents ............................................................................................................vii Chapter 1 General Introduction and Literature Review ................................................... 1 1.1 Introduction and Aims ................................................................................. 1 1.2 Wildlife Management .................................................................................. 4 1.2.1 Urban wildlife management .................................................................. 5 1.3 Case study AWI........................................................................................... 8 1.3.1 Reproduction ...................................................................................... 10 1.3.2 Survival .............................................................................................. 13 1.3.3 Population trends................................................................................ 14 1.3.4 Site-fidelity .......................................................................................... 17 1.3.5 Habitat use.......................................................................................... 20 1.3.6 Structure of the thesis......................................................................... 21 Chapter 2 The pest status of Australian white ibis ( Threskiornis molucca ) in urban situations, and the effectiveness of egg-oil in reproductive control ............ 24 2.1 Abstract .................................................................................................... 24 2.2 Introduction ..............................................................................................

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