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Re: Thou Shalt Not Climb!
So, what I'm wondering, is how did selection take place for pre-perching
birds that were landing in trees with zero adaptations for such?
Many modern birds alight upon objects without having 'perching' feet. Gulls
and pelicans can certainly perch *upon* things (but don't have much of a
grip). I suspect that webbed bird feet in general are not very 'perchy'
(depending on exactly how you define the verb 'perch' - I can perch upon a
stool without using my feet to grip it :) ).
As far as early birds went, grasping feet could have been used first to grap
prey, which later proved useful for perching upon branches. That's not to
say that earlier non-grasping feet prevented birds from alighting on objects
though - or that early volant predators necessarily used their raptorial
feet to do a lot of tree perching either.
GIS / Archaeologist geo cities.com/dannsdinosaurs
Melbourne, Australia heretichides.soffiles.com