March 16, 2006
Experts Argue Over Ivory-Billed Woodpecker
WASHINGTON -- Was it or was it not an ivory-billed woodpecker? Experts are still arguing a year later, while bird fanciers flock to the part of Arkansas where the bird in question was said to have been seen and heard.
The issue takes wing again in the Friday's issue of the journal Science, with one set of researchers arguing that the bird videotaped last year was probably a common pileated woodpecker and another group stoutly defending the identification as an ivory-bill.It's an important distinction because the ivory-billed woodpecker had been thought extinct. And if one is still alive, there probably are more.
Identification of the bird in the videotape as an ivory-billed woodpecker "rests on mistaken interpretations of the bird's posture," according to a research team headed by David A. Sibley of Concord, Mass.
In addition, they contend that "several features visible in the video contradict identification as a typical ivory-billed woodpecker, and that other features support identification as a pileated woodpecker."
Not so fast, say John W. Fitzpatrick and colleagues, responding that their critics are misinterpreting the underwing pattern of a pileated woodpecker, are using inaccurate models of takeoff and flight behavior and are mistaking "video artifacts" as feather patterns.
Sibley, a bird illustrator, said he was at first excited by the announcement that the ivory-billed woodpecker had been sighted and even went to Arkansas hoping to see one for himself.
After returning home he looked again at the video and "It struck me, watching it then, it could be a pileated woodpecker. I felt like I'd been kicked in the stomach," he said in a telephone interview.
He then analyzed the video closely along with audio tapes and other sighting reports with his co-authors and concluded that the evidence wasn't sufficient to prove the bird was an ivory-billed woodpecker.
The quality of the video is not good enough to clearly see the white stripes on the bird's back that would mark it as ivory-billed, and the large amounts of white seen while it is flying can be accounted for by the underside of the wings of a pileated woodpecker, they wrote.
Ivory-billed woodpeckers may well exist in the area, they said, but the available evidence doesn't yet prove it.
Fitzpatrick, of the Cornell Laboratory of Ornithology in Ithaca, N.Y., responded that the angle of the video shows white plumage on the upper surface of the wings that is unlike the pattern on a pileated woodpecker, and the black trailing edge of the pileated wing is absent from the bird they found.
In addition, Fitzpatrick and colleagues said data on the wingspan and flight characteristics of the bird point to it being an ivory-billed woodpecker.
The identification of the bird also was questioned last year, prompting the Cornell researchers to provide audio tapes of the bird for a group of ornithologists in California. The recordings included the unusual double-rap sounds that ivory-bills produce as well as distinctive nasal sounds they have been known to make.
Whatever the outcome of the debate, the search for the woodpecker has been a boon for the Big Woods section of Arkansas with tourist business up an estimated 30 percent and shops selling woodpecker memorabilia. Indeed, Brinkley, Ark., even held a woodpecker celebration in February.
On the Net:
Cornell Ornithology Laboratory http://www.birds.cornell.edu