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Re: Science feather strength debate



Don Ohmes <d_ohmes@yahoo.com> wrote:

> That said, doesn't the issue of limited upstroke due to to skeletal
> constraints short-circuit the usefulness of extant bird analogs?


Yes, definitely.  Flightless birds such as the kakapo and kagu, which
use their wings for gliding, are capable of flapping their wings.  In
both these birds, the supporting musculature is too weak to sustain
flight.


The kakapo flaps its wings to extend the length of glides when
descending from trees.  This is discussed in GSP's 'Dinosaurs of the
Air', as a possible analog for incipient flight behavior in the
theropod ancestors of birds (p.122).  However, this hypothesis depends
on the ability to raise the humerus above the horizontal.


The kagu also uses its wings during gliding descents, but I don't know
if it flap its wings kakapo-style to increase the horizontal range of
the glide.  However, it is my understanding that the kagu flaps its
wings when running over uneven terrain and/or to boost running speed.




Cheers

Tim