The Worldtwitch Ivory-bill page has recently been updated with a new, skeptical headline. New doubts are also expressed in the wording of the text, such as this addition: "Those claiming that [the] Ivory-billed Woodpecker still exists have thus far failed to meet their burden of proof."
For comparison, here is the same page from Google's cache.
Subscribe to:
Post Comments (Atom)
Posts
2 comments:
I believed and continue to believe that the best evidence produced thus far for the continued existence of Ivory-billed Woodpecker consists of the tapes of double rap drums made by unmanned recording devices in the White River National Wildlife Refuge in February 2005. However, Jackson has revealed for the first time that the automatic recorders were in some cases located near roads and developed areas. Someone playing back tape of another Campephilus drum either in the hope of locating Ivorybills or in an attempt to fool the searchers might be responsible. Another possibility that I initially had rejected is that another species of woodpecker could be responsible for the double raps, but Jackson, a leading expert on North American woodpeckers, believes that another species could have given the drums. With the double rap tapes cast in doubt, that leaves only substantially weaker evidence supporting the claim that Ivory-billed Woodpecker somehow survived for more than 60 years in a patch of marginal habitat.
The video is of such poor quality that it is difficult to form a definitive opinion. It could be typical, non-leucistic Pileated Woodpecker that simply appears to show too much white for a Pileated due to lighting conditions. A partially leucistic Pileated, as hypothecated by some, seems to me to be almost as remote a possibility as Ivory-billed.
As Jackson notes, the "kent" calls recorded in White River NWR might be attributable to Blue Jays or people.
As for sight records, see Stuart Keith's humorous article in the Auklet, in which he demonstrated based on sight records that the Ivory-billed Woodpecker is a common bird throughout the U.S., including Central Park. "The Little-known Status and Distribution of the Ivory-billed Woodpecker" by Strix nebulosa, The Auklet, Centennial Issue, New Yauk, 1983.
One unexpected consequence of the Arkansas Ivory-billed Woodpecker search is that the calls taped by Dennis in Texas around 1970 finally were analyzed. The results, published in the recent special issue of North American Birds, show that in all likelihood they were given by a different species. As the photos furnished to Lowrey were obvious fakes, that leaves no undisputed physical evidence since the demise of the birds on the Singer Tract in the 1940s.
I hope that Ivory-billed Woodpecker does in fact continue to exist in Arkansas, but I become more skeptical as time goes by with no concrete proof. The neotropical Campephilus are noisy and quite easy to locate and see. From historical reports, it's clear that the Ivory-billed Woodpecker was similarly very conspicuous.
Should the Arkansas search fail, perhaps there will be sufficient interest to mount a search in remote Cuban pine forests where the Cuban subspecies might have survived. The well-publicized search in Cuba a few years ago that produced only highly questionable sight records was in suboptimal, second growth habitat where Ivory-billed Woodpeckers are unlikely to occur.
Imperial Woodpecker is more likely to survive than Ivory-billed, as the last bits of old-growth forest in the highlands of western Mexico have only recently been logged. While there may no longer be sufficient prime habitat for breeding, a few birds may still exist and could wander for considerable distances in search of food. Thus, I find the recent sight record from Barranca del Cobre to be more plausible than Ivory-billed Woodpecker sight records.
The WorldTwitch Ivory-billed Woodpecker page began as a response to the highly-publicized and well-funded search for birds in the Pearl River area of southeastern Louisiana. I wrote in 2002:
"The fact that the [same] observer 'saw' them on two widely separated occasions in the same unsuitable habitat increases my skepticism from 99% to 100% minus epsilon. Yet much time, money and effort are being devoted to this ridiculous goosechase, now in its third year (2002), particularly since a corporate sponsor (Zeiss) has emerged. The searchers are as likely to find Judge Crater as Ivory-billed Woodpeckers.
"The site of the purported observations is in second growth forest close to I59 at the Louisiana/Mississippi border northeast of New Orleans (Map). In 1938 James Tanner found the area completely cut over and devoid of C. principalis. It seems highly improbable that birds would have moved there when their last stronghold in old growth hardwood forest on the Singer Tract in northern Louisiana was logged. Indeed, there have been no undisputed observations in the US since the 1940s, although Campephelis woodpeckers (at least the Neotropical species) are quite easy to locate at considerable distance from their distinctive double raps. Furthermore, they often drum from the same hollow tree day after day."
Jackson reveals that some of the ARUs were thusly situated. He does not state tht the ARUs that made the recordings were so located. The exact locations of those recordings have not been made public.
Post a Comment