Grey Falcon
Falco hypoleucos Gould, 1841
A research project by
Jonny Schoenjahn, PhD
Perth, Western Australia.
This site was created on 30 May 2004.
Updated on 20 June 2022.
Adult Grey Falcon Falco hypoleucos.
Photo © Gary Porter.
The Grey Falcon is one of Australia's rarest birds of prey, and without doubt its least studied. Among the reasons for this deficiency are the remoteness of the locations where these birds live and the species' scarcity, making data collection slow and tedious. In 2003 I commenced an Australia-wide study with the aim to increase our knowledge of the species. The study is ongoing ever since. It focuses on key aspects of the species' ecology, including diet, reproduction, juvenile dependence, long- and short-term movements, and general behaviours.

Thanks to the wonderful help of many people who kindly reported their sightings to me I was able to collect sufficent data to support the Grey Falcon's inclusion (in 2020) in the list of threatened species under the Environment Protection and Biodiversity Conservation Act 1999, category ‘Vulnerable’. The identification of threats to the Grey Falcon is the next step toward recommending conservation measures for this enigmatic species.

Adult Grey Falcon Falco hypoleucos.
Photo © Chris Field.
The first free-flying Grey Falcon captured, an adult male. July 2007.
Photo © Jonny Schoenjahn.
Photo © Jonny Schoenjahn.
This bird was banded with a coloured metal band on each lower leg, the individual colour combination allowing future identification of the individual. The bands are well visible in flight and when the bird is perched.

Since then, a further twenty individuals where marked, including nine that were fitted with solar-powered satellite transmitters. The bird below is the male partner of a breeding pair; it was captured and tagged on 9 October 2010 while its two young were near fledging age. In 2011, the same male was again the partner of a pair breeding in the same nest. The position data generated by the satellite transmitters help to understand the ecology of the species because the data help to assess home range size and understand the movements between breeding seasons, nest site choice, the influence of weather (i.e. short-term) and climate (long-term), and much more.

Adult male Grey Falcon with satellite transmitter. 9 October 2010.
Photo © Jonny Schoenjahn.
In April 2014 in the Pilbara region of Western Australia, the juvenile female pictured below was captured and satellite-tagged. This bird and its transmitter produced unique location data over more than two years, revealing that this individual's movements were nomadic.
Ready to be released: Grey Falcon juvenile female. Western Australia, 4 April 2014.
Photo © Jonny Schoenjahn.
The main challenge for the fieldwork remains the task to find the birds, and in particular to locate active nests. Clearly this project would be impossible without the wonderful help of many people kindly reporting their observations to me. Importantly, all information and photos you may send me will be kept strictly confidential – my study would have got bogged years ago if I didn't.

Please please refrain from publicizing the location of your observation. This includes online bird record sites such as ebird, Eremaea birdlines, BirdLife Australia's ongoing bird atlas, etc. The species is so rare and hard to find that a nest site, once published, will inevitably be visited by birders and bird photographers and this may have detrimental effects on the breeding result. In the light of the extremely small population any disturbance will have a strong impact on the fate of the species as a whole.

This project is not possible without your help!

Please keep sending in your records.

Information will be kept strictly confidential.


I am also a member (adjunct staff) of the Walter-Furlong Lab , School of Biological Sciences, The University of Queensland.
The project is kindly supported by:
The Peregrine Fund, Boise, Idaho.
Dampier Bunbury Pipeline, Western Australia
Western Australia's Parks and Wildlife Services.
CSIRO - (Australian) Commonwealth Scientific and Industrial Research Organisation.
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If you experience difficulties with this page or have any comments or suggestions, or a photograph of a Grey Falcon which could be included here, please send me an e-mail.
Colour-band combinations used in this study.
This Web site is © Copyright 2004-2022, and owned by
Dr. Jonny Schoenjahn
Perth, Western Australia