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Re: Marsupial forelimbs... or rather hindlimbs

On Mon, 26 Nov 2007, T. Michael Keesey wrote:
On 11/26/07, Dann Pigdon <dannj@alphalink.com.au> wrote:

Also; perhaps live young have an advantage over eggs in some circumstances? Most birds have specific requirements for nesting sites, whereas viviparous bats can breed just about anywhere there is a surface for their young to cling to.

Come to think of it, avians are basally ground nesters -- when did tree-nesting begin? (And which clade is it limited to?)

Well, not to be a smart ass, but when suitable trees and nesting material were available. As in, I'm not sure a tree fern would be suitable. By the late cretaceous, there were representatives of current species (like oaks) as I understand. Conifers are very old, tho, so surely some of these would be suitable and tree nesting could have happened very early on.