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Re: Orenstein's pedestrian arguments.



From: Ronald Orenstein <ornstn@inforamp.net>
 > 
 > Later in his message Mr Bois refers to what I think may be the real
 > critical difference between small terrestrial bipeds and quadrupeds.

Good point. I know of no likely true fossorial archosaurs, with the
one - maybe - exception of _Mononykus_.

[And I have doubts even about that one].

 > As noted, flightlessness does not mean defenselessness even for small
 > forms.  A number of flightless or near-flightless birds can reach quite
 > high in trees by strong leaps (eg lyrebirds, which are very poor
 > flyers and may be incapable of flying upwards to any degree).

Hmm, you reinforce my judgement that many small dinosaurs could be
at least partly arboreal.  This example even helps counter some of the
objections based on the stiff tails of advanced coelurosaurs.  A more
unlikely tree-dweller than a lyrebird I can hardly imagine.

 > Highly important as I suggest.  Other burrowers include some petrels,
 > motmots, some swallows, some parrots (eg the Burrowing Parrot or
 > Patagonian Conure of southern South America), some kingfishers,
 > a few woodpeckers and probably others that I have forgotten.

I belive the pygmy owl of the Sonoran desert may be a (limited)
burrower.

 >- there may have
 > been (am I right on this, folks?) whole communities of forest
 > creatures of the period whose existence has entirely escaped us.

I would say "there likely were".  Between the cladistic and fossil
evidence for considerable Late Cretaceous bird diversity, and the
lack of intermediates between the majot pterosaur groups, I would say
there is good evidence for much hidden diversity.

[I also suspect a rather greater diversity of early mammals than
we currently know of].

 >  Are we to assume, for
 > instance, that Anurognathus was the ONLY pterosaur of its type, or
 > the tip of the iceberg?

At a guess - closer to the tip of the iceberg than otherwise.
 > 
 > Guam rails are flightless, but this is not the best example as the Brown
 > Tree Snakes that got loose on Guam have devastated ALL the native land
 > birds, both flying and flightless - the Guam Flycatcher, for instance, a
 > perfectly good arboreal flyer, is now extinct.  ...

Which just shows that general anti-predator adaptations are more
important than flight per se.  So this is actually good support for
*your* position on the (relative) unimportance of flight in this
regard.
 > 
 > Frankly, I doubt that the information exists - these are notoriously
 > difficult birds to study.  However, given the way the Handbook is put
 > together I suspect that if the authors had meant to restrict the
 > statement to marsh birds they would have done so.

Indeed by casting a wider net than just rails I can cite an
example of a brushland bird that tends to avoid flight - the
locally common brown thrasher. It is noisier than rails, but
that doesn't matter, as it is very agile in the branches of the
dense chaparral.  It tends to fly only to cross open spaces, or
perhaps to go to its nests (I have not seen their nests, so I do
not really know *where* they nest - they are hard enough to see
when foraging).

swf@elsegundoca.ncr.com         sarima@ix.netcom.com

The peace of God be with you.