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IVORY-BILLS  LiVE???!  ...

=> THE blog devoted to news and commentary on the most iconic bird in American ornithology, the Ivory-billed Woodpecker (IBWO)... and... sometimes other schtuff.
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"....The truth is out there."

-- Dr. Jerome Jackson, 2002 (... & Agent Fox Mulder)

“There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.”

-- Hamlet

"All truth passes through 3 stages: First it is ridiculed. Second, it is violently opposed. Third, it is accepted as self-evident."

-- Arthur Schopenhauer






Sunday, July 24, 2005

 
-- SOME HISTORY --

James Tanner wrote the “definitive” study of Ivory-billed Woodpeckers in N. America in 1942 as a doctoral thesis at Cornell. His is a meticulous and wonderful study of... the half-dozen-or-so Ivory-bills he specifically observed over time at the Singer Tract in Louisiana. While he gathered information and anecdotes on Ivory-bills from throughout the Southeast, Tanner’s actual observations were retricted to a small sample of birds at a single La. location, making the generalizability of his findings and conclusions somewhat suspect. Conclusions about Ivory-bill behavior, and dietary and habitat needs are based largely upon what the birds at the Singer Tract appeared to utilize and enjoy, which is NOT NECESSARILY the same as what the species REQUIRED for survival.
As Tanner himself stated, so accurately,

“The chief difficulty of the study has been that of drawing conclusions from relatively few observations... entirely confined to a few individuals in one part of Louisiana... The conclusions drawn from them will not necessarily apply to the species as it once was nor to individuals living in other areas.”

Yet, in ensuing years these words were largely ignored as ornithologists turned Tanner’s doctoral work into gospel criteria for all Ivory-billed Woodpeckers.

At the time of his studies, Tanner concluded that fewer than 30 Ivory-bills remained in the entire Southeast scattered amongst just three states: Louisiana, Florida, and S. Carolina. In fact, some believe there may have been 200+ Ivory-bills left in the 30’s dispersed across far more locales in very small groups. Further, Tanner believed a single pair of the birds needed a minimum of 6 square miles of forest tract for survival even though the only slightly smaller-sized Pileated could reside on far less territory. Almost certainly non-breeding, juvenile Ivory-bills could make do with much smaller tracts of land while biding time. It is simply difficult to tease out what the bird merely ‘preferred’ from what it truly ‘needed’ to survive.

Since the late 1940’s hundreds of Ivory-bill “reports” have come in, the vast majority being cases of mistaken identity or outright hoaxes. Still, several dozen sightings over the years bear enough credibility as not to be easily dismissable. Moreover, one must wonder how many other sightings have been made over time by people (non-birders) who didn’t have a clue what they were seeing, nor that it was worth reporting... OR, by people who knew EXACTLY what they were seeing and deliberately chose NOT to report it for fear of the dismissive judgments that would be cast their way? My guess is we would be stunned if we knew the actual number of Ivory-bill encounters that occurred in recent decades, while “experts” were cavalierly pronouncing the species extinct!

(material originally published in Chapel Hill Bird Club Bulletin 'Special Edition' 2005)

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