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Re: Life of Birds (vertical running)
----- Original Message -----
From: "Tim Williams" <firstname.lastname@example.org>
Sent: Wednesday, October 10, 2001 10:45 PM
> I was referring to gross morphology. _Archaeopteryx_ and _Rahonavis_
> more in common than any other bird.
> (Except perhaps that "Proornis" thing.)
Isn't that probably a confuciusornithid?
> >*Rahonavis* seems to have been the better secretary bird. [...]
> The secretary bird (_Sagittarius serpentarius_), like most (?all) extant
> birds of prey, has a pes designed for grasping and holding prey. I don't
> think the pes of _Rahonavis_ is specialized for this purpose. The
> claw of _Rahonavis_ may have been useful for *subduing* prey already
> but (as in _Archaeopteryx_) the pes seems to have had little utility in
> initially siezing the prey. The flexor tubercles are very weak, and the
> hallux is too high.
True. Well, I think while the secretary bird catches its prey with a foot
and kills it with its beak AFAIK, *Rahonavis* is likely to have killed its
prey with its sickles claws immediately rather than catching it. Just
landing/stepping on the prey and <tchac>.
> This is the easy part. The little chickadee is helped down by a
> known as "gravity".
So they simply jump down? Might an extensively fused sacrum/pelvis, as seen
in pygostylians (the more the closer to Neornithes), be required, or does it
> >Are there such steep dunes?
> "Steepness" may not have been the primary problem. [...]
I see. Thanks! :-)