Re: Avian extinction ref.

[MICHAEL HABIB <habib@jhmi.edu>]

> And Carolina parakeets, and great auks...

Again, these are good thoughts, and may in fact be straight-up overkill 
extinctions.  However, has this been shown with any degree of confidence?  I 
was under the impression that Carolina parakeets, for example, were a 
multiple-factor extinction.  Great auks might be a good example of a predation 
kill.

Since oceanic birds are so important to this thread, here is an additional line 
of questioning that might be interesting to pursue:

Oceanic birds are prevalent on islands (for obvious reasons, the main one being 
they can reach them).  This means that many oceanic species have restricted 
ranges (at least breeding ranges, the actual range of an albatross is 
practically unbounded at sea).  However, it also means that they are among the 
predators most likely to make it to oceanic islands and prey on isolated 
populations of other seabirds.

So here's the question: do extant seabirds show up as being polarized towards 
very rare and very common, with few species in between?  We could take a look 
at the IUCN redlist and make a tally to see.  Could be interesting (or maybe 
not at all).  This wouldn't actually demonstrate cause, but the speculation 
above at least makes me curious what the pattern of threat is in groups like 
Alcids, Larids, and Procellariiforms.

--Mike Habib