Re: Flight capablities of Archie & Confucius? Not so good...

[evelyn sobielski <koreke77@yahoo.de>]

> > So what business did _Archaeopteryx_ have evolving in
> the first place?  It's something I've been wondering about
> quite a lot...
> 
> Didn't it live on islands?

Actually, that's where it gets complicated. All we know is that what seems by 
all accounts to be *immature* individuals were drifting around near the shore 
of islets.

The adults *might* have lived on what larger islands were in the vicinity - and 
which also had something that might be called "forest" IIRC -, and which are 
more likely to have had Archie-predators than the islets where the carcasses 
wound up.

In any case, there are still the about as (in)capable East Asian taxa, which 
seem to have done just fine against terrestrial predators (and may actually 
have evolved in a decidedly predator-rich environment), but which disappeared 
when fully powered ocean-crossing "birds" became plentiful.

But as I said, it just takes an accessible lookout point, and even marginal 
unpowered flight capability becomes a definitive winning ticket. Under such 
circumstances, it might even be so useful as to make any significant step 
towards truly *self-powered* flight a *dis*advantage (energy-wise).

A major factor to remember: no grass, and generally sparse ground-cover. Enough 
stuff to get in the way of both your feet and your vision, if you're a small 
bipedal theropod; hardly ever enough to hide in.

It is perhaps significant that kakapos are effectively flightless, but still 
use their wings to parachute to safety from trees etc without getting hurt. For 
all that can be said, Archie had a better wing loading than a kakapo. Also 
consider _Threskiornis solitarius_, which was becoming neoflightless but used 
downhill glides to escape when pressed. It was (as evidenced by its remains) 
more capable of flight than Archie.

We cannot infer Archie's behavior very well, but at least the raw physical 
constraints are very much in favor of it having been capable of attack- or 
escape-glides from whatever marginally elevated spot it could reach. And it is 
remarkable that such behavior is the last vestige of flight capability that is 
lost as modern theropods become neoflightless. _T. solitarius_ is a 
particularly notable case, but unfortunately the information about is is very 
fragmentary. In any case, escape glides seem to have been the only flight 
behavior ever recorded for it, but anatomically it would still have been 
capable of much more.


Regards,

Eike