Movements and Genetics of
Grey Falcons
Falco hypoleucos Gould, 1841.
ID hints
Grey Falcon adult Falco hypoleucos, central southern Queensland, June.
Photo © Richard Fuller.
Identifying raptors in the field can be challenging, especially when light is poor, viewing angles are less than desirable, and encounters are brief. Typically however, all three come together.

Richard Fuller's wonderful shot (above) is one of a series. It would be quite ambitious to identify the bird by that one photo, let alone if the observed had only caught a glimpse like that.

Nankeen Kestrel Falco cenchroides, Gluepot Reserve, South Australia, November.
Photo © Kay Parkin.
A Nankeen Kestrel. Long-tailed, the black tailband just discernible, wings narrower and more to the front of the body than in the Grey Falcon in the photo below:
Grey Falcon adult Falco hypoleucos, SW Queensland, October.
Photo © Jonny Schoenjahn.
Another common suspect is the Brown Goshawk. When seen from below, the best fieldmark is that its wings grow narrower towards the base. In general, the Goshawk does not appear quite as stocky, and there is no conspicuous bright orange-yellow colour visible on the head or on legs and feet.
Beware of calling your bird a Grey Falcon on the basis of black wingtips, they are not diagnostic of Grey Falcon. Check out the nest photo.
Brown Goshawk Accipiter fasciatus, near Pine Creek, Northern Territory.
Photo © David Hartland.
In flight, Grey Falcons have broad wings that are broadest at the base, a solid body, and a comparatively short tail with no distinct terminal or sub-terminal band.
All in all the Grey Falcon has a rather stocky appearance.

Black wingtips are an obvious feature from above, even under poor viewing conditions; see Richard Fuller's photo at the top of this page. From below however, black wingtips are not diagnostic of Grey Falcon and may not be discernible at all, as Chris Field's stunning shot proves:

Grey Falcon adult Falco hypoleucos, central southern Queensland, November.
Photo © Chris Field.
The identification of juvenile birds has also led to some confusion and consequently, false conclusions. In May, young Grey Falcons - i.e. birds in their first year - look like the one below. The most conspicious feature is the black 'blotching' of the white underparts. On the youngster on Stephen Knights' photo you can see the first grey adult feathers with the faint black centre line emerging on the breast. One or two of the juvenile feathers, white with the large black streak, may soon be one of the last bits of evidence of that individual's young age. Cere and orbital ring are not yet of the bright orange-yellow of the adult bird, and the bases of upper and lower mandible as well are not as yellow as in the adult. Only legs and feet have almost acquired the adults' bright orange-yellow.
Not quite discernible on this photo are the brownish 'shoulders', i.e. the upper outer feathers of the folded wing. Just exactly when the birds acquire those brown 'shoulders' and when they moult out of them I don't know yet.

In May, typically the Grey Falcon family is still together, a behaviour quite unlike other falcon species. Whether the young are then still truly dependent on their parents or whether they only enjoy free food and the company is difficult to find out.

Plenty of scope for further research.

Grey Falcon juvenile, southwestern Queensland, mid May.
Photo © Stephen Knights.
For a broader discussion of identification hints, please see
Schoenjahn, J. (2010). Field identification of the Grey Falcon Falco hypoleucos. Australian Field Ornithology 27: 49-58.
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