Friday, July 06, 2007

The Ivory-billed debate

Louis Bevier (here and here) has just launched a new Website, Ivory-billed debate. In it, he provides an overview as to what the debate is and is not about, and what is at stake (i.e., “the credibility of observational evidence”). He also ponders the philosophical question, “Is there hope?”

Next, he examines in fine detail the plumage features detectable in the bird shown in the Luneau video (the one that Fitzpatrick et al. claim shows an Ivory-billed Woodpecker, Campephilus principalis), compares them to the features one would expect to see in Ivory-billed and Pileated (Dryocopus pileatus) woodpeckers, and concludes that “it is almost certainly a normal Pileated Woodpecker.”

He then examines the wingbeat frequency of the bird in the Luneau video, compares it to those of the Pileated Woodpecker, and concludes:
Empirical evidence demonstrates that the bird in the Luneau video flaps at the same rate as a fleeing Pileated Woodpecker.
Finally, he provides a video analysis of three Pileated Woodpeckers video-taped in a flight cage in Maine. His finding:
Several launch sequences were recorded confirming precise wing and tail movements that match the Luneau video. Deinterlaced video fields match precisely launch sequence from Arkansas in terms of timing of wing movement and reduced or blurred out black training edge to underwing. These launch mechanics were identical to free-flying Pileated Woodpeckers videotaped elsewhere in Maine.
The Luneau video was the most persuasive evidence that Fitzpatrick et al. had to support their claim that at least one Ivory-billed Woodpecker was present in Arkansas in 2004. Bevier’s Website is still under construction and edits will continue, but it seems to me that his preliminary analysis has done considerable harm to the claims of Fitzpatrick et al. This is sure to elicit much additional public debate, one that will be interesting to follow in the weeks and months ahead. Will Fitzpatrick and others at the Cornell Lab of Ornithology respond to this challenge to their credibility?

2 Comments:

Anonymous Anonymous said...

Will Fitzpatrick and others at the Cornell Lab of Ornithology respond to this challenge to their credibility?

No, just as they did not seriously challenge Collinson. I think that at this point, they are simply hoping this whole thing dies down and goes away. Entering into a debate, especially with a losing hand, only raises their profile once more.

July 06, 2007 12:51 PM  
Blogger Bill Pulliam said...

Still interpreting edge artifacts as plumage, still ignoring the details of flight dynamics to focus just on wingbeat rate...

Suppose I shouldn't necessarily fault him too much, though, since Cornell have failed to bring up either of these lines of analysis in their repsonses, either.

July 06, 2007 3:51 PM  

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