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Re: Brooding over dinos



At 09:14 PM 18/08/98 -0700, you wrote:
>Tom Hopp wrote:
>
><< highly engineered for BROODING >>
>
>Dinogeorge wrote:
> 
><All you need, basically, is some kind of cover. 

A point that occurs to me about the brooding scenario:  if wings are so vital
for brooding, why is it that many flightless birds have greatly reduced their
size?  This is even true for a species like the Flightless Cormorant of the
Galapagos, a hot, dry area where one would thing the ability to shade the
young
would be vital.

Instead, the flightless birds that have retained large wings, like the Ostrich
and Kagu, use them in display and carry ornamental wing plumes (ostrich) or
striking wing-patterns not visible when the wings are closed (Kagu).  I might
have expected that if wing-brooding were that important birds like rheas and
emus would have retained large wings too - their behaviour is not that
different from, that of an ostrich.

Again, I remain unconvinced based on living birds that brooding is likely to
have been a major driving factor in the evolution of large wings; the evidence
suggests display as a more likely explanation if locomotion is not to be
involved.
--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@inforamp.net