Re: Again: origin of bird flight

[Ronald Orenstein <ornstn@home.com>]

At 06:37 PM 17/03/01 +0100, David Marjanovic wrote:
> True, but I disagree with the "Pouncing Proavis" hypothesis:
> 1. It's mantra time: There Were No Trees At Solnhofen. (I don't think 3 m
> high bushes are suitable for such pouncing.)

Further mantra: so what?  Just because Archaeopteryx happened to live in 
the Solnhofen ecosystem does not mean that (a) it evolved there, (b) flight 
evolved in that type of ecosystem or (c) Archaeopteryx really is the First 
Bird so anything about how it lived apples directly to how flight 
evolved.  There are plenty of closely-related living birds today that 
occupy quite different habitats (not to mention other groups of animals - 
if baboons were the only fossil primates would we be forced to conclude 
that primates did not evolve in trees?).  Archie just happened to be the 
one that fossilized - it could have had very close relatives in tall forest 
elsewhere.

> 2. *Archaeopteryx* (and *Microraptor*, and even the larger
> *Sinornithosaurus* whose skull is only 13 cm long) surely didn't hunt prey
> that could be hunted this way. Insects, or, in the case of Archie, fish seem
> more probable (and *small* tetrapods in the case of *Sinornithosaurus*).

Or small frogs, lizards etc - which (in forests) probably lived in trees 
too, just as they do today, and sat on leaves or thin limbs (I still think 
pouncing up, rather than down, followed by parachuting, makes more sense).

> Or for steering underwater... just like pelicans do today with their stiff
> tail feathers. (c) Ebel 1996

I'm afraid I can see not the slightest resemblance between Archaeopteryx 
and any swimming bird.  The limb and body proportions are about as wrong as 
they can be - I would be utterly astonished if it could, or did, swim 
underwater.

Fits underwater flight, too.

Underwater flyers today are highly specialized in ways Archaeopteryx simply 
is not.  For one thing, birds that do this today (alcids, penguins, 
scoters) have long bodies and short limbs - quite unlike Archaeopteryx.

> Just a question here -- is there still anyone on this list who thinks that
> the abovementioned groups are not secondarily flightless? :-)

Well, I for one think that the matter is far from proven, though suggestive.


--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
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