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Re: hovering diversity (was Re: Ornithurine diversity)

----- Original Message ----- From: "Mickey Rowe;893-2446" <mrowe@lifesci.ucsb.edu>
To: <dinosaur@usc.edu>
Sent: Tuesday, July 15, 2008 7:45 AM
Subject: hovering diversity (was Re: Ornithurine diversity)

Dann Pigdon (dannj@alphalink.com.au) wrote:

I once watched a small falcon [...] It literally hung in the air
without beating it's wings at all by facing into the wind

And Jim Cunningham (jrccea@bellsouth.net) responded:

Facing into the wind will not help the animal to maintain altitude.
Something else must have been going on as well, in order to provide
energy for hovering at constant altitude.

I fear that either your misunderstanding Dann or the birds know something you don't. The phenomenon is called "kiting", and I see it all the time on the bluffs above the beaches near Santa Barbara.

You just proved my point. They are using orographic lift (the updraft caused by the wind blowing against the bluffs). That's a common hovering mechanism where available. Where some form of atmospheric energy is not available (wind alone does not provide such energy), the birds usually have to resort to the 'flutter' stroke to hover at constant altitude, by making use of full alternating momentum reversal generated by the wings (looks quite different from the more conventional flapping stroke).