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The life of birds



The first episode of Dave Attenborough's "The Life of Birds" aired
here in Australia on sunday. There were some nice pterosaur CGI/model
scenes (albeit a bit stiff), and even a CGI archaeopteryx (for once
not shown with gawdy parrot-like plumage). Nothing to get Spielburg
worried though.

Dave (or at least his researchers) makes a good argument on why
flight may have developed. He uses the fact that many birds have
become flightless in predator-free environments to suggest that
flight may have originally arisen to escape predation. Of course
it doesn't say anything about the ground-up or trees-down theories,
but it is interesting none-the-less.

My questions are thus:

Wouldn't the development of flight get you away from terrestrial
predators (out of the frying pan), but within convenient snatching
distance of pterosaurs (into the fire)?

What of ratites such as the ostrich, emu, rhea and cassowarie?
Did they develop on islands and eventually move to the mainland
when they had reached a certain predator-resistant size, or is the
flightlessness/non-predation relationship over simplifying the
situation?

Feel free to foster lively debate - or to ignore the questions 
completely. It's your call.

-- 
____________________________________________________
        Dann Pigdon
        GIS Archaeologist
        Melbourne, Australia

        Australian Dinosaurs:
        http://www.geocities.com/capecanaveral/4459/
        http://www.alphalink.com.au/~dannj
____________________________________________________