Forshaw's Australian Parrots book describes Glossy Black Cockatoo as:
extremely buoyant flight with having slow, shallow wing beats, which differ
markedly from the full flapping wing beats of the ..... YTBC............ So
a different suggestion.
Neither does directly mean that speed of flight is different. If it does it
would not suggest that Glossy Black Cockatoo is the slower one, which was
the question posed by Mark. I wouldn't use slow flight as a feature to
identify a Glossy Black Cockatoo cf YTBC.
Philip
-----Original Message-----
From: Birding-Aus On Behalf Of
Sandy Gilmore
Sent: Friday, 13 June 2014 10:03 AM
To:
Subject: Black Cockatoos in flight
Hi everone,
A very timely question since I frequently get Yellow-tailed Black Cockatoos
flying over and infrequently get Glossy Cockatoos flying over.
While enjoying the sunset a few days back I had both species fly over a few
minutes apart and it was abundantly obvious that Glossy Cockatoos flap their
wings at twice or more the rate of Yellow-tailed Black Cockatoos.
This is in the situation where I presume both were returning to their night
time roosts and were flying high over a mixture of forest and cleared
paddocks.
Aerodynamics experts would be able to explain this inter-specific difference
based substantially on their relative body weights, and wing areas and wing
spans.
See http://jeb.biologists.org/content/150/1/171.full.pdf
On another matter I have increased my White-throated Needletail sightings
over summer by an order of magnitude, plus observing other interesting
birds, by taking time to observe the sunset as often as possible.
Cheers,
Sandy
Sandy Gilmore
Arid Zone Ecologist
Bush Heritage Australia
"Morinda" 240 Mafeking Road, Goonengerry NSW 2482.
Conservation Support Centre
Level 5, 395 Collins Street, Melbourne Vic 3000
www.bushheritage.org.au<http://www.bushheritage.org.au/>
T: +61(0)2 6684 9178
M: +61(0)427 686 985
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