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Re: Science feather strength debate



Jason Brougham <jaseb@amnh.org> wrote:

> I would like to see how the humerus of Geococcyx stacks up. Meinzer (The
> Roadrunner, 1993, Texas Tech U. Press) reports that they usually ascend to
> their nests in trees by leaping upward to a series of branches, and not by
> flying. I've been imagining similar behavior in an animal like Anchiornis
> or other small troodontids - with long legs and probably somewhat
> underpowered flight apparatus.


The roadrunner (_Geococcyx_ spp.) has a zygodactyl foot that is
adapted for perching, as is the case with all cuckoos (Cuculidae).
Apparently the zygodactyl pes, with two toes pointing forward and two
toes of almost the same length pointing back, does not interfere with
the ability of roadrunners to run fast on the ground.  Roadrunners and
other ground-cuckoos have shorter wings and longer distal hindlimbs
than arboreal cuckoos, but they retain excellent perching abilities.

Thus, I'm not sure it's a good idea to use roadrunners as analogs for
troodontids.  Troodontids, as well as dromaeosaurids and
_Archaeopteryx_, do not have a pes that is adapted to perching.

It is possible that non-ornithothoracine paravians could climb trees
using all four limbs, which obviated the need for a perching foot.
But this is merely speculation.



Cheers

Tim