Re: Gansus Bird-Dino Connection - Penn Press Release

[Tim Williams <twilliams_alpha@hotmail.com>]

Scott Hartman wrote:

> Climbing hoatzin chicks aren't perching...at least while climbing.

Their parents have a strange form of perching.  Aside from the anisodactyl 
feet, the sternum is also used to help support the body ("sternal 
perching"), probably because adult hoatzins are so front-heavy due to the 
huge crop.

> Cassowarys are reported to occasionally scale trees, and I doubt very much 
> that they perch.

I've heard that seriemas (Cariamidae) can do the same thing, and they use 
their enlarged inside claws.  I didn't know about this behavior in 
cassowaries - but I also doubt that they perch.  :-)  However, humans are 
advised to climb a tree should they ever be chased by a cassowary, 
suggesting that the climbing abilities of cassowaries are not very good.  
;-)

I've yet to see anything in the literature on *how* cassowaries and seriemas 
climb trees.  Do they use branches, or the trunk, or both?

> If a bird is arboreal without wrapping its toes 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.

Yes, that's exactly what I was driving at.  Aside from Dan's examples of 
cavity nesters, that is.

Cheers

Tim