RE: From the ground up flight: anecdote

[Tim Williams <twilliams_alpha@hotmail.com>]

> IF birds evolved from the trees down - as flight got better, I would expect
> to see tree climbing abilities getting worse, as flight would become the
> prefered method of getting up 


Yes, but... this requires that the first flying theropods could both (a) launch 
from the ground and (b) land in trees.  


If microraptorans, _Archaeopteryx_, and confuciusornithids could climb trees at 
all, then all four limbs would have to be used in climbing.  As soon as flight 
abilities became decent enough, sure, then the bird could launch from the 
ground.  If the foot was capable of perching, the bird could also land on a 
tree-branch.  All of this would remove the need to involve the hands in 
climbing, so the manus (and carpus) could then be absorbed into the wing. 


The question that people like Feduccia, Martin, Olshevsky, and other 
"trees-down" diehards skim over is this: If the ancestors of birds were all 
exclusively arboreal, and flight evolution was exclusively "trees-down"... why 
are the arboreal abilities of _Archaeopteryx_ so piss-weak?  If birds had 
gliding and flying ancestors going all the way back to the Triassic, why does 
the Late Jurassic _Archaeopteryx_ show so few (if any) climbing or perching 
adaptations?


> (can any bird "climb" a tree now? the most I
> see is gripping on the side of a trunck one and moving a few inches
> inbetween flight)


I've seen footage of Japanese shearwaters climbing up tree trunks by bracing 
their wings against the trunk, and using their feet to push forward.  But the 
trunks are bent over at an angle, not vertical.


Cheers

Tim
_________________________________________________________________
See how Windows connects the people, information, and fun that are part of your 
life.
http://clk.atdmt.com/MRT/go/msnnkwxp1020093175mrt/direct/01/