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Thursday, March 15, 2007

Ivory-billed Woodpecker Video in Question

These are various digital images of Pileated Woodpeckers in flight that I photographed in Florida.






A paper in the BMC Biology journal puplished today concludes that the Ivory-billed Woodpecker captured in the 2004 Arkansas video by David Luneau, which was used as proof of its existence by Cornell Laboratory of Ornithology, might really be a Pileated Woodpecker.

Scientist Martin Collinson of the University of Aberdeen in Scotland looked at videos of Pileated Woodpeckers in flight and compared them with the Luneau video, analyzing both wing beat speeds and pattern of the wings in flight. The conclusion in the abstract of his paper is:

"The identification of the bird filmed in Arkansas in April 2004 as an Ivory-billed Woodpecker is best regarded as unsafe. The similarities between the Arkansas bird and known Pileated Woodpeckers suggest that it was most likely a Pileated Woodpecker."

"Collinson says he is disappointed by his finding. He still wants to believe that the Ivory-billed Woodpecker exists but says the evidence does not support that conclusion", according to USA Today. Cornell stands by their original opinion, that the bird in the Luneau video is an Ivory-billed Woodpecker.

You can see the abstract and the whole paper, including images from the Luneau as well as the Pileated videos, here.

The paper says that some of the "Key findings of the video analysis are:

“1. Pileated Woodpeckers flying near-horizontally away from the observer show much more white in poor-quality video than would be expected from their general plumage pattern. They present an appearance of a black-bodied bird with largely white wings and black wingtips, very similar to the bird in the Luneau video ....The expected appearance of the upperwing of Pileated Woodpecker – mostly black with a small white patch at the base of the primaries – is often not seen, and is only clearly resolvable when birds are flying near-vertically before landing on a tree trunk; something the bird in the Luneau video did not do.

2. The black trailing edge to the underwing of Pileated Woodpecker is often very inconspicuous and may disappear completely. Due to motion and flexion of the wing, the black trailing edge is much more obvious towards the wingtips. This produces an apparent plumage pattern that matches the patterns shown by the Luneau video bird."

It is interesting to look at some of my various digital photos of Pileated Woodpeckers in flight in light of this information. My fourth photo, in which the bird was flying directly away from me, does show a lot of white on the right wing, with a black wing tip and the black trailing edge almost disappears.

It seems to us that continued study of Pileated Woodpeckers, ranging from their flight, behavior, habitat, scaling evidence, etc., is important and will help in distinguishing them from potential Ivory-billed Woodpeckers.

Photos @ Lillian Stokes, 2007

2 comments:

Liza Lee Miller said...

It seems clear that data, data, data and an open mind to whatever answer that data provides is the only way to answer the question of whether or not the Ivory-bill still exists. Thanks for continuing to look at the debate with that open mind.

Sara said...

Thanks for the interesting post and I certainly agree with Liza Lee's comments. One issue about the Luneau video which impresses me, is that even in frame by frame review, there does not appear to be any red color about the head of the bird. Anyway, all the press attention does indirectly highlight the need for habitat preservation. So, I hope the discussion continues loud and long.