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Re: Senter 2006, Confuciusornis, and humeral mobility



> So let's just stick to your original suggestion that we
> just consider
> steady flight for now. We know that there are many modern
> birds, such as
> Shearwaters (http://www.youtube.com/watch?v=Cjmtt_B_i4A) and
> condors, that
> have great difficulty getting airborne yet they may still
> live much of
> their lives on the wing.

Different reasons although it is fundamentally the high wing loading. Both use 
different kinds of soaring and have optimized winds for each purpose. 
Procellariiform (and generally pelagic birds') wings are optimized for 
prolonged flight above (and bouncing on, sort of) ground effect; they are too 
narrow in take-off but overall such birds are not particularly heavily built 
(even albatrosses). Their wingspan evolved beyond a point where takeoff is 
easily possible/their body mass couldn't follow suit.

Condor wings and generally any "slab-of-wood" looking wing shape is optimized 
for utilizing thermal convection over land. This is usually in birds which are 
large-bodied and heavily built. Their body mass evolved beyond a point where 
takeoff is easily possible/their wingspan couldn't follow suit.

In short, _Diomedea exulans_ on average clocks just above _Vultur gryphus_ in 
wingspan, and just below it in weight, and I think the wing area of the latter 
is noticeably larger.

_Confuciusornis_ was presumably closer to the first, but not really comparable. 
Its limited takeoff skills were mostly limited by its plesiomorphies, not 
apomorphies.


Regards,

Eike