[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Gliding kakapos



GSP1954@aol.com wrote:

> In the Attenborough bird series, was there a scene showing New Zealand
> kakapos climbing trees and then gliding?

No.  The first episode showed the kokako, or "blue-wattled crow," from the
dense forests of New Zealand's North Island, behaving in a "squirrel-like"
fashion, scampering along branches and leaping horizontally from branch to
branch in search of food.  Their actions closely resemble the horizontal
interbranch leaping that you proposed for protobirds on page 215 of
_Predatory Dinosaurs of the World_ (as opposed to the traditional trees
down vs. ground up hypotheses for the origin of avian flight).  On the
other hand, these extant birds were shown to be quite capable of flying
from tree to tree; they are not flightless.

The same program, "The Life of Birds With David Attenborough," episode
one, also showed footage of New Zealand's rare flightless kakapos, (the
largest parrots in the world), clambering through the forest, feeding
among the branches of trees, and a male puffing up its air sacs and
booming to attract a female.  But this bird was not seen gliding on this
program; I don't know if it does, although I _suppose_ that it would
flutter down a few feet to the ground rather than hopping down, seeing as
its wings are of good size, albeit rendered rather useless by the
degenerate flight muscles and sternum.  (Episode one also featured a
pterosaur, a kiwi, a seriema, an ostrich, _Dinornis_ and moa).

Episode two, "The Mastery of Flight," opens with a nocturnal procession of
Japanese shearwaters ascending a bent tree in order to initiate flight by
falling into the air.  Sir David Attenborough explains that this
particular tree is of a most desirable configuration, having a horizontal
"takeoff" limb 40 feet in the air, so the birds on view had walked from as
much as 30 to 40 yards away to climb this one tree.  It was amazing to me
how adept the shearwaters were at climbing the tree with their webbed
feet.  Once airborne, the shearwaters were quite competent fliers; it is
their takeoff which required the assistance of a suitable launch
platform.  Mr. Attenborough explained that other shearwaters, which do not
live in the forest, take off from cliffs.  (This episode, by the way, also
shows an albatross "taxiing," or getting a running start to become
airborne, and includes slow motion footage of a pigeon leaping into the
air to commence flying).

Best always,

-- Ralph W. Miller III       gbabcock@best.com

"You say 'kakapo,' I say 'kokako'..." (with apologies to Fred Astaire).