Addendum to RE: Longer Tails in Birds: Functional "Re"Evolution

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

I forgot to mention that, of all modern flying birds, the most
"front-heaviest" species is probably the hoatzin (_Opisthocomus hoazin_),
which has a very capacious gut for digesting large amounts of leaves.
("Alimentary, my dear hoatzin", as a certain very clever British
paleontologist once said...)

Hoatzins perch in trees; but they don't have a long or heavy tail to
counterbalance the front part of the body.  Instead, they rest their sternum
on the branch for additional support, which has developed a special callus
for this purpose.  I don't know of any other bird that employs this method
of "sternal perching"; but I've wondered if it might have been used by
Mesozoic birds (or their relatives) that had poor "foot-perching"
capabilities.  Impossible to prove of course...


Tim



------------------------------------------------------------ 

Timothy J. Williams 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 3163