Re: large fossil birds

[Tim Williams <twilliams_alpha@hotmail.com>]

Patrick Norton wrote:

> > But on all three accounts, I don't think we'll find any Mesozoic bird 
> > that's heavier than _Dromornis_ <
>
> And why not? What's so magical about the 500 kg limit for a ground dwelling 
> bird?

What I meant to say was "I don't think we KNOW of any Mesozoic bird that's 
heavier than _Dromornis_."  In theory, there's no reason why a terrestrial 
bird couldn't have exceeded 500 kg.  Or an aquatic bird, for that matter.  
I'm reminded of those giant whale-like penguins in "After Man".  :-)

> > or has a broader wingspan than _Argentavis_.>
>
> I might agree with this, since A. magnificens is probably about as large a 
> a feathered flapping vertebrate flyer can get.

I wonder why...?  Why couldn't birds get as large as the azhdarchids?

Mickey Mortimer wrote:

> The largest Mesozoic volant bird was Enantiornis leali, at about a meter 
> long.

Thanks, that's the one I was looking for.

> You won't find anything over the Cenozoic mass limit (~550 kg) for birds in 
> the Mesozoic without invoking Utahraptor, Deinocheirus or the larger 
> therizinosaurs.

Of course, using Ax's definition (followed by Olshevsky) ALL dinosaurs are 
birds, so _Argentinosaurus_ could be the largest avian.  :-)

Cheers

Tim