Apparent Ivory-billed Woodpecker sighting may be a mistake
Ivory-billed Woodpecker sighting may be a mistake
mongabay.com
March 14, 2007
A new study casts doubt on the apparent rediscovery of the Ivory-billed Woodpecker in Arkansas.
J. Martin Collinson, a researcher at the University of Aberdeen in Scotland, says that the sighting of the thought-to-be-extinct bird is a case of mistaken identity. Using video analysis, Collinson argues that ornithologists have confused the Ivory-billed Woodpecker (Campephilus principalis) with the similar Pileated Woodpecker (Dryocopus pileatus).
“Video analysis of Pileated Woodpeckers in escape flights comparable to that of the putative Ivory-billed Woodpecker filmed in Arkansas shows that Pileated Woodpeckers can display a wingbeat frequency equivalent to that of the Arkansas bird during escape flight,” he wrote. :The critical frames from the Arkansas video that were used to identify the bird as an Ivory-billed Woodpecker are shown to be equally, or more, compatible with the Pileated Woodpecker.”
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Hopes that the ivory-billed woodpecker survived extinction were renewed last September along the Florida Panhandle when another team of scientists from Auburn and Windsor universities reported sightings and retrieved a number of audio recordings of the bird’s distinctive double knock. Still, none of the evidence to date has provided the definitive proof of the bird’s existence that skeptics demand. Caption text courtesy of University of California – Berkeley. Image courtesy of Larry Chander/Cornell Lab of Ornithology |
Collinson notes that “as Pileated Woodpeckers fly away from the camera, their plumage is hard to distinguish from the Ivory-billed Woodpecker’s,” according to a release from BioMed Central. “He suggests that the Pileated Woodpecker’s distinctive black trailing wing edges can be spotted in the Luneau video as the wings stroke downwards. Previous analysis suggested these were the black wingtips of the Ivory-billed Woodpecker.”
Original sighting set off twitching frenzy
A group of ornithologists caused a stir in April 2004 when they claimed they had spotted the Ivory-billed Woodpecker (Campephilus principalis), a species that had been believed to be extinct since 1944. The apparent rediscovery triggered a bird-watching frenzy in areas once inhabited by the conspicuous bird but has so far not turned up any conclusive evidence of the existence of the species. Researchers have even enlisted the help of NASA and installed robotic cameras in hopes of spotting the bird.
Collinson says these efforts may be in vain.
“The identification of the bird filmed in Arkansas in April 2004 as an Ivorybilled 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.”
“With no verified reports in the USA for over 50 years, it seemed impossible that a crow-sized black, white and red bird should have eluded the nation’s ornithologists, hunters and conservationists in heavily populated South-eastern USA for so long.”
John Wall, an avid birder who runs WorldTwitch.com, a birding web site, expresses similar sentiments.
“There is no credible evidence that the North American subspecies of Ivory-billed Woodpecker Campephilus principalis survived after the demise of the Singer Tract birds in the 1940s after the last substantial patch of old-growth habitat was destroyed,” he states on WorldTwitch.com.
“Further, Campephilus are noisy, conspicuous, and relatively tame. From the reports of Audubon, Tanner and Dennis (in Cuba), it is clear that the same was true of principalis,” Wall told mongabay.com. “I have encountered Campephilus species on numerous occasions while birding in forest and never have had any difficulty seeing them well.
“What can only be another routine case of misidentification of the common Pileated Woodpecker Dryocopus pileatus in good Pileated but poor Ivorybill habitat in Arkansas has been promoted as the latest Ivorybill ‘rediscovery'” concluded Wall.
Nevertheless the tale of a real-life phoenix has spurred interest in conservation efforts of the Ivory-billed Woodpecker’s habitat — hardwood swamps and pine forest in the southern United States — which was largely destroyed by logging in the early part of the 20th century. The reported sighting has also sparked tourism in east Arkansas.
The paper, titled “Video analysis of the escape flight of Pileated Woodpecker Dryocopus pileatus: Does the Ivory-billed Woodpecker Campephilus principalis persist in continental North America?”, is published today in the open access journal BMC Biology.
