Re: Science feather strength debate

[Jason Brougham <jaseb@amnh.org>]

Mr. Paul,

In your recent posts about the Nudds and Dyke Paper you have called their 
conclusions silly.  I wholeheartedly agree with you that they should have 
presented good figures for proximal rachises along with their conclusions and 
that this missing data weakens the paper. But on other points I fear you have 
seemed dismissive.

Correct or not, Nudds and Dyke have provided an explicit and empirical 
methodology and their conclusions can be supported or falsified on their own 
terms. In accomplishing this they have set a  high standard for scientific 
methods.

I would suggest that their method calls for a response in kind, and that you 
should recruit a team of eager young biologists and engineers to build 
aerodynamic models to test, for example, whether the overlapping feather vanes 
of Confuciusornis would strengthen the wing enough to prevent buckling.

You are free to analyze whether the proportionately long arms and short legs of 
Confuciusornis correlate in a statistically significant way with flying animals 
and do not overlap with non - flying animals.

You are also free to analyze whether there is a statistically significant 
correlation between flight abilities and the formation of abundant  lacustrine 
fossils.

All of these are scientifically valid responses, but I don't feel that 
categorical dismissals are.

You wrote that you were irritated that Nudds and Dyke (and "lots of folks") did 
not cite Dinosaurs of the Air. Speaking for myself, I feel that your book could 
have been far more persuasive and influential if its methods had been explicit 
and if it had proposed methods by which your hypotheses could be falsified.

For example, I could not find the calculations that you used to estimate body 
mass for Archaeopteryx in either DA or Predatory Dinosaurs of the World. In the 
former you do mention Yalden's calculations, but then you state that his 
estimate is too high and you lower it without providing any mathematical reason 
for doing so. In your technical comment on Nudds and Dyke you show two 
elevation drawings: silhouettes of a pigeon and of Confuciusornis, as your only 
evidence that the pigeon weighs more. But a pigeon is a three - dimensional 
object, and riven with pneumatic air sacs. If the pigeon was more voluminous 
you did not calculate this, and you provide no evidence as to whether the 
pigeon is more or less dense than a more basal bird. Then you go on to say that 
the lower mass of the Munich Archaeopteryx makes the feathers "several times 
stronger" when you must have meant that they have several times less loading. 
But my point is that you are less persuasive when you simply write that this is 
so than you would be if you provided calculations that can be checked by your 
readers.

If we hypothesize that Confuciusornis was capable of powered flight, this 
hypothesis must be falsifiable in order to be scientifically valid, correct? So 
perhaps one day  an overwhelming body of evidence will demonstrates that it was 
a littoral scavenger that roosted in trees overhanging lakes, and parachuted 
down to the shoreline to forage. You and I think that this is highly unlikely, 
but that doesn't matter.  What matters is that we design experiments rigorously 
so that their results will be believable.


Jason Brougham
Senior Principal Preparator
American Museum of Natural History
jaseb@amnh.org
(212) 496 3544