RE: Hell Creek (long)

[John Bois <jbois@umd5.umd.edu>]

On Sun, 2 Jun 2002, Allan Edels wrote:

> I want to remind everyone that nearly ALL THE ANIMALS THAT WEIGHED MORE
> THAN 30 KG DISAPPEARED!  I'm not sure of the numbers of small
> (non-avian) dinosaurs that existed in the late Maastrictian, perhaps
> someone can supply this info.  My current understanding is that dinosaur
> genera had reduced drastically prior to K-T - mostly the larger sized
> animals (_T. rex_, _Triceratops_, etc.).  It seems like all the small
> dinosaurs were birds!

If true, this is a startling fact!  Why, since species don't just
_surrender_ niche space, would there be fewer small non-avian
dinosaurs?  This is a smoking gun of sorts.  Were birds
outcompeting/preying on small non-avian dinosaurs?  Did birds do the same
thing to pterosaurs?