Ecology of the Grey Falcon Falco hypoleucos – current and required knowledge

Australia’s endemic Grey Falcon is an iconic but elusive bird of the arid interior. Whilst reviews of its ecology and status are more than 25 years old, new targeted studies include a population size estimate that is considerably lower (<1,000 individuals) than the one previously advanced (<5,000 individuals). According to this revised estimate, the Grey Falcon’s national conservation status should be considered to be ‘Vulnerable’, but the species is not declared threatened under Australian national legislation. A ‘threatened’ listing could, however, be expected if support for the lower population size estimate becomes available. A prerequisite for investigations aiming to test that estimate, and to determine what may threaten the future of this species, is a more comprehensive understanding of the species’ ecology. Our analysis of the relevant literature on the species’ ecology shows that the Grey Falcon is unique among its congeners in persisting exclusively in a hot arid/semi-arid environment, and in its strong dietary restriction. Further, young Grey Falcons may live in the close company of their parents up to a year after fledging, and this would be unique among raptors of that size if correct. Finally, the species’ environment is characterised by extreme, unpredictable climatic events, and understanding how these birds interact with these environmental features is key to assessing their possible responses to climate change.