Emu Emu Society
Journal of BirdLife Australia
RESEARCH ARTICLE

Patterns in the abundance of White-bellied Sea-Eagles (Haliaeetus leucogaster) in Jervis Bay, south-eastern Australia

Jennifer A. Spencer A C and Tim P. Lynch B
+ Author Affiliations
- Author Affiliations

A Centre for Environmental Restoration and Stewardship, Australian Catholic University, PO Box 968, North Sydney, NSW 2059, Australia.

B Jervis Bay Marine Park, PO Box 89, Huskisson, NSW 2540, Australia.

C Corresponding author. Email: j.spencer@mackillop.acu.edu.au

Emu 105(3) 211-216 https://doi.org/10.1071/MU04030
Submitted: 31 May 2004  Accepted: 10 August 2005   Published: 12 October 2005

Abstract

Between 2001 and 2003, we undertook 137 boat surveys for White-bellied Sea-Eagles, to investigate the abundance and distribution in Jervis Bay, New South Wales, Australia. Adult sighting rates differed between years, being highest in 2003, and both adult and sub-adult Sea-Eagle numbers differed between seasons. High sighting rates of sub-adults each autumn (April) were thought to reflect not only the appearance of locally fledged juveniles but also an influx of immature birds (2–4 years old) from outside the study area. Although it was common to observe single adult birds and pairs throughout the year, influxes of sub-adults in autumn generally led to an increase in observed group size. The largest group of Sea-Eagles observed contained eight individuals and most groups larger than two contained both adults and sub-adults. Observability was related to age-class and behaviour, with perching behaviour common in adults but relatively rare for sub-adults. The density of Sea-Eagles, and sub-adults in particular, was highest on the undeveloped northern and southern headlands, which are military and conservation reserves, compared with the urban settlements on the western shore of the study area. Furthermore, Sea-Eagles were only observed perching in forest reserves interspersed between urbanised areas, despite the appearance of suitable perches throughout the coastal suburbs. In view of these results, we discuss the possible implications for management of Sea-Eagle habitat.


Acknowledgments

The authors thank the NSW Marine Parks Authority; R. Norriego for her assistance in developing the project in April 2001; boat drivers F. Clements and J. Brown; numerous volunteer field assistants who generously gave up their time; P. Olsen, G. Bryon, D. Breen, B. Creese, C. Gray, M. Byrne, J. Shephard, N. Mooney and one anonymous reviewer for their invaluable advice on draft manuscripts. We also thank V. Mansbridge and L. Finch for providing GIS support and data layers, and NPWS Library staff and the Macquarie University Graduate School of the Environment for assistance with literature.


References

Bilney, R. J. , and Emison, W. B. (1983). Breeding of the White-bellied Sea-Eagle in the Gippsland Lakes Region of Victoria, Australia. Australian Bird Watcher 10, 61–68.


Burgman M. A., and Lindenmayer D. B. (1998). ‘Conservation Biology for the Australian Environment.’ (Surrey Beatty: Sydney.)

Cho G., Georges A., Stoutjesdik R., and Longmore R. (1995). ‘Jervis Bay – A Place of Cultural, Scientific and Educational Value.’ (Australian Nature Conservation Agency: Canberra.)

Dennis, T. E. , and Lashmar, A. F. C. (1996). Distribution and abundance of White-Bellied Sea-Eagles in South Australia. Corella 30, 93–102.


Emison, W. B. , and Bilney, R. J. (1982). Nesting habitat and nest site characteristics of the White-bellied Sea-Eagle in the Gippsland Lakes Region of Victoria, Australia. Raptor Research 16, 54–58.


Favaloro, N. (1944). The White-Breasted Sea Eagle along the Murray Valley. Emu 43, 233–242.


Fortescue M. E. (1995). Biology of the Little Penguin Eudyptula minor on Bowen Island and at other Australian colonies. In ‘The Penguins: Ecology and Management’. (Eds P. Dann, I. Norman and P. Reilly.) pp. 364–394. (Surrey Beatty: Sydney.)

Fowler J., Cohen L., and Jarvis P. (1998). ‘Practical Statistics for Field Biology.’ 2nd edn. (John Wiley and Sons: Chichester, UK.)

Fraser, J. D. , Frenzel, L. D. , and Mathisen, J. E. (1985). The impact of human activities on breeding bald eagles in North-central Minnesota. The Journal of Wildlife Management 49, 585–592.


Garnett S., and Crowley G. (2000). ‘Action Plan for Australian Birds 2000.’ (Environment Australia: Canberra.)

Heinsohn, T. (2000). Predation by White-breasted Sea-Eagle Haliaeetus leucogaster on phalangerid possums in New Ireland, Papua New Guinea. Emu 100, 245–246.
CrossRef |

Hoenig, J. M. , Robson, D. S. , Pollock, C. M. , and Jones, K. H. (1993). Scheduling counts in the instantaneous and progressive count methods for estimating sportfishing effort. North American Journal of Fisheries Management 13, 723–736.
CrossRef |

Hollands D. (1984). ‘Eagles, Hawks and Falcons of Australia.’ (Thomas Nelson: Melbourne.)

Lane, S. G. (1979). Summary of the breeding seabirds on New South Wales coastal islands. Corella  3, 7–10.


Lehner P. D. (1996). ‘Handbook of Ethological Methods.’ 2nd edn. (Cambridge University Press: Cambridge, UK.)

Lintermans, M. (1988). The distribution and breeding of the Little Penguin on Bowen Island Jervis Bay. Corella 13, 123–125.


Lynch, T. P. , Wilkinson, E. , Melling, L. , Hamilton, R. M. , Macready, A. , and Feary, S. (2004). Conflict and impacts of divers and anglers in a marine park. Environmental Management 33, 196–211.
CrossRef | PubMed |

Marchant S., and Higgins P. J. (Eds) (1993). ‘Handbook of Australian, New Zealand and Antarctic Birds. Volume 2. Raptors to Lapwings.’ (Oxford University Press: Melbourne.)

Mooney, N. , and Brothers, N. (1986). Sea eagles’ greatest problem is nest disturbance, says NPWS. Fintas 9, 39–41.


Newton I. (1979). ‘Population Ecology of Raptors.’ (Buteo Books: Shipman, VA.)

Pollock K. H., Jones M. C., and Brown T. L. (1994). Angler survey methods and their applications in fisheries management. American Fisheries Society Special Publication Series25. (American Fisheries Society: Bethesda, MD.)

Savory, R. (1989). Prey remains from Osprey and White-bellied Sea-Eagle nests on North Keppel Island. Queensland Naturalist 29, 76–77.


Shephard J. M. (2003). A multi-scale approach to defining historical and contemporary factors responsible for the current distribution of the White-bellied Sea-Eagle Haliaeetus leucogaster (Gmelin, 1788) in Australia. Ph.D. Thesis, Griffith University, Brisbane.

Shephard, J. M. , Catterall, C. P. , and Hughes, J. M. (2005). Long-term variation in the distribution of the White-bellied Sea-Eagle (Haliaeetus leucogaster) across Australia. Austral Ecology 30, 131–145.
CrossRef |

Smith, G. C. (1985). An analysis of prey remnants from Osprey Pandion haliaetus and White-bellied Sea-Eagle Haliaetus leucogaster feeding roosts. Emu 85, 198–200.


Stalmaster M. (1987). ‘The Bald Eagle.’ (Universe Books: New York.)

Stalmaster, M. V. , and Kaiser, J. L. (1997). Flushing responses of wintering bald eagles to military activity. The Journal of Wildlife Management 61, 1307–1313.


Steidl, R. J. , and Anthony, R. G. (1996). Reponses of bald eagles to human activity during the summer in interior Alaska. Ecological Applications 6, 482–491.


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