The ivory-billed woodpecker is back from the dead ... again. A team of scientists has chosen to withdraw a paper that would have challenged the rediscovery of the long-thought-extinct bird, first reported 28 April in Science (ScienceNOW, 28 April).
The paper, in press with the Public Library of Science (PloS) Biology, had argued that video evidence presented in the Science paper was not convincing enough to warrant such an extraordinary claim. It would have been the first public statement of doubts about the strength of the evidence that have been quietly harbored by many ornithologists and birders since an initial wave of euphoria greeted the Science study.
The paper was withdrawn yesterday after its first two authors, ornithologists Richard Prum of Yale University and Mark Robbins of the University of Kansas in Lawrence, listened to recordings of the woodpeckers' calls. The recordings--clipped from 17,000 hours of tapes from automatic recording units placed in Arkansas's White River National Wildlife Refuge--were provided Sunday by ornithologist John Fitzpatrick of Cornell University, lead author of the Science paper. "They're stunning," Prum said. Robbins agreed, saying he considers the recordings "irrefutable evidence" of the existence of at least two individual ivory-bills.
According to Prum and Robbins, the recordings feature a series of distinctive "kent" vocalizations lasting at least 15 seconds, and a pair of "double-raps" that are diagnostic for woodpeckers of the ivory-bill's genus, Campephilus. On the tape, one distant double-rap is followed several seconds later by a nearby double-rap. Both Robbins and Prum have extensive experience hearing Campephilus species in the Neotropics, and Robbins says "the timing of the response was perfect." Prum agrees, saying the social interaction apparent from the tape eliminates other possibilities such as the similar-looking pileated woodpecker, gunshots, or creaking trees. Robbins said the two birds could be either a mated pair or two territorial birds of the same sex.
Prum says his team "still stand[s] by every word of the manuscript," but that in light of the new acoustic evidence, he and his colleagues have chosen to refrain from publishing their critique. The team also says its decision was influenced by concerns that a battle in the literature would hurt conservation efforts in Arkansas, where the Nature Conservancy continues to purchase crucial habitat for the woodpecker.