[canberrabirds] Why are the C. Sparrowhawk & B.Goshawk so similar?

["Jeremy O'Wheel" <>]

The problem with the cockatoo theory is that in Tasmania there is good
reason to think Sulphur-crested Cockatoos are recently introductions, but
all the Grey Goshawks are white morph. Also Grey Goshawks have a white
underside regardless of morph, and that's the side prey would normally see.
I suspect the underside is white for sky camouflage (like the
White-breasted Sea-eagle and a number of other diurnal birds of prey),
while the upper surface possibly represents genetic drift, or sexual
selection.

Jeremy
On 12/01/2013 11:56 PM, "Rosemary Royle" <> wrote:

> During our latest trip to Australia, up above Gunlom Falls in the NT we
> spotted a dead branch laden with Sulphur-crested Cockatoos plus what
> appeared to be a smaller white cockatoo. It wasn't, it was a white-morph
> Grey Goshawk, and it had obviously chosen to perch with the cockatoos. .
>
> Only on reading this thread does that sighting make sense.
>
> Rosemary
>
> Rosemary Royle, Wales, UK
>
>