Birds as dino-killers

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

When you finish laughing, hear me out.  Leigh Van Valen says that causes
of extinction are often a matter of taste, that complex synergy is usually
the rule.  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.  If birds could do this to pterosaurs, they
must also be able to cause trouble for small to medium-sized non-avian
dinosaurs.  If it is true that there was a reduction in the diversity 
of these size ranges among dinosaurs, birds must be considered prime
suspects.  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.  And a
new dawn...
Thankyou.  Thankyou, very much.