The number of reports on Birding-aus would certainly indicate that white
morph Grey Goshawks associate with white cockatoos but is this why they are
white or is it just an association that has occurred because they are white?
Greg
Dr Greg. P. Clancy
Ecologist and Birding-wildlife Guide
PO Box 63 Coutts Crossing NSW 2460
0266493153 0429601960
-----Original Message-----
From: Dick Jenkin
Sent: Sunday, January 13, 2013 9:39 AM
To: 'Greg and Val Clancy'
Cc:
Subject: RE: [Birding-Aus] [canberrabirds] Why are the C. Sparrowhawk &
B.Goshawk so similar?
Hi Greg and all
Not sure on any scientific basis either but I have seen a white morph Grey
Goshawk flying with a group of Sulphur-crested Cockatoos around the Dungog
area. The presumption being they are using the cockatoos as camouflage to
"sneak" up on unsuspecting prey. Maybe other people have had similar
experiences.
Cheers
Dick Jenkin
Dungog ( 70kms north of Newcastle NSW )
-----Original Message-----
From:
On Behalf Of Greg and Val
Clancy
Sent: Sunday, 13 January 2013 9:27 AM
To: Jeremy O'Wheel; Rosemary Royle
Cc: COG line; Birding Aus; Denise Goodfellow
Subject: Re: [Birding-Aus] [canberrabirds] Why are the C. Sparrowhawk &
B.Goshawk so similar?
Whether there is any scientific basis for the ‘cockatoo theory’ or not I am
sure that the white underparts would assist in camouflage in the sky.
Greg
Dr Greg. P. Clancy
Ecologist and Birding-wildlife Guide
PO Box 63 Coutts Crossing NSW 2460
0266493153 0429601960
From: Jeremy O'Wheel
Sent: Sunday, January 13, 2013 12:09 AM
To: Rosemary Royle
Cc: COG line ; ; Greg ; Denise Goodfellow ; Birding Aus
Subject: Re: [Birding-Aus] [canberrabirds] Why are the C. Sparrowhawk &
B.Goshawk so similar?
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
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