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Re: feather symmetry

Bill Adlum wrote:

>Tracy Ford wrote:
>>>That makes the *symmetrical* feathers on _Protoarchaeopteryx_ a bit
>>>difficult to fathom, doesn't it?
>>>Ilja Nieuwland
>>Not if it was a swimmer...
>Wouldn't asymmetrical feathers be just as useful for hydrodynamics as they
>are for aerodynamics?  Anyone know if penguin feathers are symmetrical?

Feather asymmetry is a bit of a red herring.  Asymmetry is an adaption to
power flight (take-off from a standing start, flying at low air speeds),
thus it is present in most, if not all, modern flying bird.  However,
having symmetric feathers does not mean that a bird cannot fly.  Provided
it takes a long enough runn up (and has long enough legs) or if it leaps
out of a tree, flight is possible.  It just cannot take off from a standing
start nor manoeuvre at low speeds