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Re: T.Rex Feather Skepticism
At 05:07 PM 9/15/2005, Michael Habib wrote:
Good point; though altriciality is the ancestral condition for
passeriform birds. The more useful question would be whether
passerine birds nesting on the ground tend to become more precocial
than those that nest in trees. There is variation within
passeriform altriciality, after all.
I'm not sure exactly what is meant by this, as I do not know of any
tendency towards precociality in Passeriformes. It is true that some
ground-nesting birds, like larks, develop extremely rapidly and
fledge at an early age - 8 or 9 days in some cases - probably to
limit the risk of predation, but they are still altricial. Also,
probably the longest nestling period of any passerine belongs to the
Superb Lyrebird, a highly terrestrial species that nests on the ground.
There are some other tricks here - one study showed that the begging
calls of ground-nesting wood warblers were higher-pitched and more
difficult to locate than the calls of arboreal-nesting warblers in
the same habitat.
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