Re: Birds as dino-killers

["David Marjanovic" <david.marjanovic@gmx.at>]

> When you finish laughing, hear me out.  Leigh Van Valen says that causes
> of

_BACKGROUND_
Sorry for shouting, and I don't know what he actually said, but if he didn't
include that word, he has overlooked something very important.

> extinction are often a matter of taste, that complex synergy is usually
> the rule.

"Usually"? True IMHO :-)

> So...if it is true that pterosaurs suffered a gradual decline
> toward the K/T, it is likely that this was caused by birds--because birds
> were the only creatures able to reach inaccesible nesting and hiding
> places of winged pterosaurs.

Azhdarchids, however, were apparently plentiful very late in the
Maastrichtian.

> If birds could do this to pterosaurs, they
> must also be able to cause trouble for small to medium-sized non-avian
> dinosaurs.

which were able to hide their nests in dense forest undergrowth, something
the large LK pterosaurs were unable to do.

> If it is true that there was a reduction in the diversity
> of these size ranges among dinosaurs,

Yes, if... any numbers available? :-)

> birds must be considered prime
> suspects.

In which case we need a LK bird capable of opening eggs. What could that be?
*Ichthyornis*? :-/

> Small-medium dinos were the agents of the
> "lawn-mower" Cretaceous ecology (large predators probably did not bother
> with shrew-size mammals).  Once they disappeared, this enabled the
> evolution of slightly larger mammals.  These mammals then crossed the size
> threshold for preying on the small offspring of very large parents.

Which, of course, assumes that there was a size increase among
end-Maastrichtian mammals of the world, and that *Gobiconodon* and
*Repenomamus* somehow failed to have similar effects.

> And a new dawn...
> Thankyou.  Thankyou, very much.

No problem. =8-)