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Re: Gansus Bird-Dino Connection - Penn Press Release
That's essentially what I meant, yes. Other good examples would actually be
pelicaniform birds (yes, I know, the group is polyphyletic) which all have
totipalmate feet (and thus a non-reversable hallux). Cormorants,
frigate-birds, and tropicbirds can (and do) all land in trees. Frigates can
nest in trees, actually, despite not being able to 'perch' in the technical
sense of the word.
Galliform birds also run (via WAIR) or fly into trees, and they do not have a
perching foot, either. Again, I'm speaking in the technical sense of having
the toes wrap the branch fore and aft, not the vernacular sense of 'perching'
which implies merely standing on a branch.
That said, I also agree that most modern birds that are truly arboreal would
have trouble being so without a true perching foot. The original reference (if
I remember correctly) was to Mesozoic birds, however, which could have climbed
quadrapedally like modern hoatzins, and thus could have been arboreal with or
without a reversed hallux.
> Climbing hoatzin chicks aren't perching...at least while climbing.
> Cassowarys are reported to occasionally scale trees, and I doubt
> much that they perch. If a bird is arboreal without wrapping its
> around the branch I assume that would be a non-perhcing bird. That
> said, I share Tim's general opinion that modern birds would have a
> difficult time being arboreal non-perchers.
> Scott Hartman
> Science Director
> Wyoming Dinosaur Center
> 110 Carter Ranch Rd.
> Thermopolis, WY 82443
> (800) 455-3466 ext. 230
> Cell: (307) 921-8333