Doctoral Thesis
Movement ecology of Australia’s avian apex predator: the Waalitj / Warlawurru (Wedge-tailed Eagle Aquila audax)
Doctor of Philosophy (PhD), Murdoch University
2024
Abstract
Almost half of the world’s 75 species of eagle are threatened, and in nearly all cases the causes are anthropogenic. The Wedge-tailed Eagle Aquila audax, Australia’s largest eagle, is widespread despite hundreds of thousands being culled during a century of European persecution. This project investigated the ecology of two breeding ‘populations’ occupying different climatic zones (‘arid’ and ‘mesic’), by monitoring 11–98 breeding pairs annually between 2009–2019, and employing satellite telemetry to better understand movements and behaviour.
The two populations supported 44 and 54 evenly spaced territories with an average of 93% occupied by breeding pairs. Mean annual productivity of 0.77 fledglings/pair/year in the mesic zone was significantly greater than in the arid zone (0.13; the lowest value recorded for the species).
A comparison of methods for estimating home range size involving analysis of data from GPS/satellite tracking and nest distribution revealed telemetry-derived (auto-correlated kernel density) estimates averaged 15.8 and 15.9 km2 for arid and mesic eagles, respectively. These were not correlated with estimates derived from nest distribution data, and were smaller than previously determined by spatial methods. Home range size was not related to estimated prey abundance or climate.
Twenty-two juvenile eagles were tracked with GPS/satellite transmitters. The duration of the nestling period was 77–114 days and males fledged significantly earlier than females. The post-fledging period was 102–221 days and there was no detectable difference between the sexes. Eagles left their natal areas between 16th March and 3rd June, with most immediately dispersing long distances, covering 192–2,212 km/month, with cumulative distances of 11,230–27,093 km in the first year of independence.
Using banding records and data from tracked individuals, survival was 96% as nestlings, 83% during the first year, and 97% and 80% in the pre-adult and adult years, respectively.
These findings provide up-to-date information on the status of the Wedge-tailed Eagle, and show this important apex predator persists in varied environments and roams widely over large expanses of country, which allows it to avoid or overcome some of the anthropogenic threats other species face in Australia’s ever-changing landscape.
Details
- Title
- Movement ecology of Australia’s avian apex predator: the Waalitj / Warlawurru (Wedge-tailed Eagle Aquila audax)
- Authors/Creators
- Simon C Cherriman
- Contributors
- Trish Fleming (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and SustainabilityJill Shephard (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and SustainabilityPenny Olsen (Supervisor) - Australian National University
- Awarding Institution
- Murdoch University; Doctor of Philosophy (PhD)
- Identifiers
- 991005726584507891
- Murdoch Affiliation
- School of Environmental and Conservation Sciences
- Resource Type
- Doctoral Thesis
UN Sustainable Development Goals (SDGs)
This output has contributed to the advancement of the following goals:
Metrics
153 File views/ downloads
423 Record Views