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Re: Advanced Features of Birds



Betty Cunningham wrote:

>Duh, if it 'rests' in trees, it's likely to live more of it's life in
>these same trees, if it 'sets' on the ground it's more likely to spend
>more time on the ground out of the trees.
> Thus indicating whether or not it's arboreal.  If early dino-birds
>perched, they were much more likely to live an arboreal existance,
>compared to ones that might have slept laying over on their sides like
>a dog, or 'setting' like a duck or emu.

This simply does not fit many modern birds.  Herons regularly roost and nest
in trees, but do all their foraging on the ground or in the water.  The same
is true to varying degrees for ibises, storks, whistling ducks and some
galliform birds.

There is nothing at all wrong with the idea of a semi-arboreal bird or bird
ancestor; there are many living birds that forage with equal ease in trees
or on the ground (chachalacas, flickers, Australian treecreepers, crows,
etc.).  The same is true for some small mammals (eg some of the smaller
cats, opossums etc) and reptiles; some lizards are more arboreal when small,
but spend more time on the ground later in life (when presumably predation
is less of a problem.)

There is no reason why Archaeopteryx or any of its predecessors had to have
been exclusively arboreal or exclusively terrestrial.
--
Ronald I. Orenstein                           Phone: (905) 820-7886 (home)
International Wildlife Coalition              Fax/Modem: (905) 569-0116 (home)
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