Coping with heat in the arid interior – what can feather structure reveal about the ecology of Australia’s desert-living Grey Falcon Falco hypoleucos?

ABSTRACT

The Grey Falcon (Falco hypoleucos) is a desert-living species restricted to the dry centre of Australia. These falcons have a number of unique life-history adaptations that may be crucial for their survival in this harsh environment, but these may, conversely, confine them to these arid regions. In this study we investigated what Grey Falcon feather structure can reveal about the ecology of the species. Specifically, we tested UV reflectance and structural waterproofing of Grey Falcon feathers, and compared these properties across other Australian Falco species. Grey Falcon feathers did not reflect unique UV peaks, nor show any significant difference in structural waterproofing when compared with closely-related sympatric falcon species. This suggests that Grey Falcon feathers have no specific adaptations to prevent the impact of UV or water on their plumage, so feather structure evidently does not help explain the persistence of this species in arid Australia. We suggest that an exploration of the physiological and behavioural thermoregulatory capabilities of this species should provide further insights in understanding how these birds cope with their extreme environment and are confined there.

KEYWORDS:

• Australia
• raptor
• bird of prey
• arid zone
• structural waterproofing
• UV reflectance

Acknowledgements

Kaspar Delhey kindly provided reflectance data, independently measured from museum specimens. Justin Cappadonna assisted with statistical analysis, while Karen Cheney, Naomi Green and Cedric van der Berg kindly assisted with spectrophotometry. The following kindly contributed feathers for analysis: Andrea Calvin (Raptor Rehabilitation Association of Western Australia), Gina Neeson (Gladstone Wildlife, Queensland), Martin Scuffins (Leigh Valley Hawk & Owl Sanctuary, Victoria), Myra Christine (former interim manager at Eagles Nest Wildlife Hospital, Queensland), Phil Pain (Eagles Heritage, Western Australia), Steve Debus (University of New England, New South Wales) and Yvonne Sitco (Western Australian Bird of Prey Centre). For permit information see Supplement 3.

Disclosure statement

No potential conflict of interest was reported by the authors.

Geolocation information

Sample collection sites are not given, so as to protect the birds of this rare species.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

JS was supported by an Australian Government Research Training Program Scholarship, and by grants from Western Australia’s Department of Parks and Wildlife, DBP (Dampier to Bunbury Natural Gas Pipeline), and The Peregrine Fund, Boise ID, USA.