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>Not as important as escaping predators, because the animals cannot know in
>advance that food will be found in new regimes. 

Please, George, Lamarck's been dead a long time! :)

No animal expanding into a new niche "knows in advance" what itvis going to
find - but a tendency to expand into an area with new food sources and fewer
competitors is clearly advantageous.

And I think flight evolved
>first in insectivorous forms, not carnivorous forms, even in the case of
>avian dinosaurs.

I include insectivory within carnivory - insects being animals, after all.

 I might just buy the evolution of avian flight as enhancing
>the pursuit of flying insects--although many insects are caught while resting
>rather than flying--but what other sources of food could be reached by flying
>that couldn't be reached by other, less energetically costly means?

It may be easier to get from one tree canopy to another by flying than by
any other method, especially if this involves trees on islands, rocky
outcrops etc.  As I have said gliding animals do this regularly, as do fruit
bats who certainly don't need flight to "capture" their prey!  Also flight
may make it easier to feed in one area and roost or breed in another
(consider the Nutmeg Pigeons, that breed on offshore islets but fly to the
Ausdtralian mainland to feed, at times covering as much as sixty or more
kilometers a day).
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
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