Greg,
I wouldn't know the answer to that one.
In my two sightings of the birds perched in the vicinity of each other, the
cockatoos were at one end of the outlier while the goshawk perched several
metres away by itself.
Denise
On 13/1/13 8:30 AM, "Greg and Val Clancy" <> wrote:
> 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: > [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: > [canberrabirds] Why are the C. Sparrowhawk &
B.Goshawk so similar?
Whether
> there is any scientific basis for the ?cockatoo theory¹ 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: [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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