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RE: Yet more on pterosaur quad arm posture






>Right, a lot of the physics here depend on what kind of roost you picture.
>
>From the sources I've read tinamous roost pretty low, especially at first,
>when the chicks can only scamper up a meter or so off the ground.
>
>Dr. Kenneth Dial has a film of a 1 day old hatchling Chukar climbing an
>incline mostly just with its feet, no hallux gripping, and with just
>short pin feathers on its wings, just sort of pushing with them.
>
>http://dbs.umt.edu/flightlab/wairontogenyhalfres.mov
>
>I've also found evidence of pinioned (distalmost phalanx and primary
>follicles surgically removed) carinate birds reaching high roosts,
>including a Pochard that climbed a chain link fence and escaped.
>
>Jason Brougham
>Senior Principal Preparator
>American Museum of Natural History
>jaseb@amnh.org
>(212) 496 3544
>
>
>
>
>
>On 7/11/13 10:08 AM, "David Marjanovic" <david.marjanovic@gmx.at> wrote:
>
>>> We agree that animals that are not scansorial do roost in trees.
>>
>>...if they can fly there. (WAIR probably counts, too.)
>>
>>If they climb there instead -- if they do what practically no bird ever
>>does today: start on the ground and climb into the crown --, they're
>>scansorial: natural selection for climbing ability kicks in, and they
>>evolve adaptations to climbing.
>>
>>Lots of terrestrial or semiaquatic birds roost in trees _because_ they
>>can do so without climbing.
>