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Re: Gregory S. Paul on Confuciusornis

The mass does not change the feather strength itself, but alters the strength 
relative to body weight, which is the key variable in question.  

--Mike H.

Sent from my iPhone

On Oct 14, 2010, at 3:46 PM, Mark Pauline <markpauline@rocketmail.com> wrote:

> In the new Science out this afternoon:
> Comment on âNarrow Primary Feather
> Rachises in Confuciusornis and
> Archaeopteryx Suggest Poor
> Flight Abilityâ
> DOI: 10.1126/science.1192963
> Science 330, 320-b (2010);
> http://www.sciencemag.org/cgi/content/full/330/6002/320-b
> I had two questions about Paul's text.
> 1) "Nudds and Dyke (Reports, 14 May 2010, p. 887) reported that the primary 
> features of the early birds Archaeopteryx and Confuciusornis were too weak to 
> power flight"
> What are these "primary features" that Paul describes? How do these features 
> confer weakness on the animals in question?
> 2) "the shallow-bodied basal bird was intermediate in mass to the 
> Munich Archaeopteryx and the deep-bodied pigeon, so the feathers were a 
> number 
> of times stronger than calculated by Nudds and Dyke (Fig. 1, A to C)."
> How does changing the mass make the feathers stronger or weaker? Isn't 
> strength 
> an inherent quality that depends on the structure of the feather?