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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