August 2, 2005
Ivory Bill’s Doubters Convinced by Tapes
LITTLE ROCK, Ark. -- Audio recordings of the ivory-billed woodpecker's distinctive double-rap have convinced doubting researchers that the large bird once thought extinct is still living in an east Arkansas swamp.
Last month, a group of ornithologists had questioned the rediscovery of the ivory-billed woodpecker, last sighted in 1944. They said blurry videotape of a bird in flight wasn't enough evidence. So a Cornell University researcher who was part of the team that announced the bird's rediscovery last spring says his group sent the doubters more evidence.
"We sent them some sounds this summer from the Arkansas woods," said John W. Fitzpatrick, director of the Cornell ornithology lab. "We appreciate their ability to say they are now believers."
The doubters had prepared an article for a scientific journal questioning whether the bird had really been found. They now plan to withdraw the article, according to a news release from Yale University, where ornithologist Richard Prum was one of the doubters.
"We were very skeptical of the first published reports, and thought that the previous data were not sufficient to support this startling conclusion," Prum said. "But the thrilling new sound recordings provide clear and convincing evidence that the ivory-billed woodpecker is not extinct."
And, the audiotape evidence seems to indicate that there is more than one ivory-billed woodpecker in the area.
"The bird that we saw had to have a mommy and a daddy," said Scott Simon, director of the Nature Conservancy in Arkansas. "We have solid evidence for one. We believe there are more."
Ornithologists announced in late April that an ivory-billed woodpecker was living in a swamp in the Cache River National Wildlife Refuge in eastern Arkansas. A Hot Springs kayaker had seen the bird a year earlier.
But bird experts at Yale, Kansas and Florida Gulf Coast universities last month questioned the evidence, saying it was only strong enough only to suggest the possibility that the bird was present, not proof. Telephone messages left for them Monday were not immediately returned.
Fitzpatrick said the audio was enough to convince them.
Using audio equipment set out in various places near the Cache and White rivers in Arkansas last winter, the Cornell ornithologists made 17,000 hours of recordings. "Some sounds were explainable only by being an ivory-billed woodpecker," Fitzpatrick said.
One portion of the tape includes a distant double-rap, followed closely by a double-rap that is very close.
"It's communication typical of the ivory-billed. It's one of the more exciting cuts from the tape," Fitzpatrick said. The communication indicates there is likely more than one bird.
He said the audio had only recently been discovered on the tapes, which are being analyzed with computer assistance. When the ornithologists announced in April that the bird had been found, the audio had not been reviewed closely enough, Fitzpatrick said.
"One of the cases they were making in their article was that we had not presented acoustic evidence," Fitzpatrick said. "We thought it was premature in April to publish the analyses."
The Cornell researchers plan to release the audio publicly at the American Ornithologists Union in Santa Barbara, Calif., Aug. 23-27.