Uh, technically, Dan, that's an example of wing-warping, not ailerons.
Bird wings are enormously complex structures. Heck, FEATHERS are
incredibly complicated - look at one under a good lens sometime, or
look up some photomicrographs. Very clever design.

Ailerons are mechanically MUCH simpler. Nature doesn't always choose
simple over efficient.

(B2431) wrote in message ...
If ailerons are so great then why don't birds have them?

They don't? Look at a hawk's wing in flight. See the long feathers on the
trailing edge of the wings? They function as ailerons.

Dan, U. S. Air Force, retired