RE: Bambiraptor complete!

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

James R. Cunningham wrote:

> I don't know
>b-raptors wingspan or ground speed, so I'll leave you to draw your own
>conclusions about the actual b-raptor wing drag -- but it ain't much.

The argument is centered not so much on whether forelimb feathers would
reduce the *ground-running* speed for the predator, but whether the forelimb
feathers would unduly effect the rapid motion of the forelimbs - such as
when they were rapidly deployed against prey.  But I would agree that, in
either case, the effect would be minimal.


>Some birds can still fly with 30% of their feathers gone.  

But wouldn't it depend upon exactly what *part* of the body the feathers
were lost from?  If the 30% loss of feathers all came from the wing tip, it
would be much more serious to the bird's aerodynamic performance than if it
that missing 30% were contour feathers from the body or along the humerus.

Similarly, if a parachuting proavian, using the feathers attached on its
hands to guide its "flight path" to the ground, were to lose those feathers,
then it could have a serious impact on the predator's behavior.  

These are all hypotheticals; but I think they're germane to some of the
current models that seek to explain how theropods came to fly.




Tim