RE: Yet more on pterosaur quad arm posture

[Jason Brougham <jaseb@amnh.org>]

According to Sick, H. (1984) Ornitologia Brasiliera, Translated Belton, W. 
(1993) Princeton University Press, Tinamus solitarius chicks can fly to a 
height of 1 meter at 5 days old. They fly to a perch about that high with their 
father, and they roost together there.

Dr. Habib assures us that, even in arboreal gliders, all aerodynamic animals 
get their initial velocity from jumps, and nothing just falls to gain speed. He 
cautions us, however, that Microraptor probably could not gain enough altitude 
to reach the top of a tree. But I assert that, even without wings, it could 
leap to a 1 meter tall perch and brood its chicks there. Scrambling up a tree 
fallen at a 45 degree angle should be no problem either. Could it have gained 
enough altitude to reach a 2 meter perch? That should be testable by 
biomechnical models, and nature shows that many animals expend effort to roost, 
even that low.

Getting themselves and their hatchlings off the ground seems to be something 
many basal birds try to do, especially if there are mammalian predators in 
their habitats, and trees to climb, and basal paravians had both. Apteryx, 
Xenicus, and many extinct island birds had the luxury of not doing so until 
humans arrived and brought rats.
________________________________________
From: owner-DINOSAUR@usc.edu [owner-DINOSAUR@usc.edu] on behalf of Thomas R. 
Holtz, Jr. [tholtz@umd.edu]
Sent: Thursday, July 11, 2013 7:20 PM
To: david.marjanovic@gmx.at
Cc: dinosaur@usc.edu
Subject: RE: Yet more on pterosaur quad arm posture

Ah, I see.

Yeah, not buying that...

On Thu, July 11, 2013 5:59 pm, David Marjanovic wrote:
>> > > they climb up there
>> >
>> > I bet this refers to WAIR. A seriema walking up a tree trunk like a
>> nuthatch is really hard to imagine.
>>
>> But as I was saying, this referred to the mammalogist's definition. So
>> climbing (with claws or with prehensile feet or what have you) is the
>> way to get up in the trees.
>>
>> So again: to mammalogists, arboreal vs. scansorial is more about WHERE
>> the animal lives & feeds v
>> about how they get there.
>
> ...Not what I'm saying. I'm not talking about whether seriemas should be
> classified as arboreal, scansorial or anything; I'm expressing incredulity
> at the explicit claim that they climb up low trees instead of flying
> there.
>


Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
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                        University of Maryland
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