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Re: Birds vs. the pterosaurs



A striking bias appears in many posts on this subject: unwillingness to
consider mundane causes--such as predation and competition--for
extinction (i.e., forces that are routine in modern ecologies)because 
of a lack of paleo evidence; and a willingness to embrace fantastic
causes--such as bolide--despite a lack of evidence connecting extinctions
to such an event.

To add balance, I think it was Tom Holtz who noted that there simply isn't
enough evidence to argue one way or another about the timing of pterosaur
extinction.  And this is also true, certainly, of birds (whose record is
very poor), marsupials (whose extinctions cooincide with placental
radiation and immigration thus making competition an equal/better
contender), and even non-avian dinosaurs for whom a record of their
extinction only appears in one (?) place--North America.  

And, it may well be that forces at work on land were different from those
operating at sea.  After all, terrestrial extinctions are not known to be
synchronous with marine extinctions.  Indeed, rough synchronicity between
these biome-level events may be cooincidental or indicative of
causation--unfortunately there is, as yet, no way of knowing which.  With
all deference, we just have to suck it up.