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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






Friday, July 13, 2007

 

-- Sustainability --



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When a species is in steep decline its numbers can fall from say 2000 to 1000 or 1000 to 500, much faster than from 40 to 20; the reason being 'sustainability' --- the fewer the number of individuals, the more likely the remaining habitat will be adequate for maintaining them; indeed a species may sustain or stabilize themselves at a low number for a significant amount of time, if hunting, predation, and other factors are held at bay --- the number of remaining individuals being lost each year, offset by the number being born/raised in what now becomes sufficient habitat for such low numbers.

Some skeptics would have it that ALL Ivory-bill habitat was at one point destroyed; of course if this had ever happened we would be facing many more extinct and endangered critters today from the 100's of species that shared that habitat. Critics contend that the Ivory-bill was a uniquely "specialized" creature, but all creatures are specialized, IBWOs, Pileateds, Northern Cardinals, Starlings, and cockroaches for that matter, only differing in degrees and forms. The specialist/generalist division is just another false and typically over-simplified black-and-white dichotomy set up after-the-fact to explain the IBWO's demise (no one called the IBWO a specialist prior to its decline). Except for Ivory-bills that were hunted, there's no indication that individual IBWOs died prematurely; rather they simply failed to reproduce adequately, and the factors impinging on that may or may not have related to specialization.

Tanner believed that less than 30 Ivory-bills remained at the time of his study, likely spread out across at least 3 locales. Many doubt his estimate, but even at that low-ball figure, 20 birds, if left undisturbed, could have maintained themselves at low numbers for many years until habitat began improving --- even in-breeding is often not as harmful to bird species as it is to mammals, and may not have been a hugely limiting factor; such low numbers could've been sustained with no necessary "bottleneck" at work. Again, despite what skeptics narrowly think, 60 years is not, not, NOT a long time for a couple dozen birds to hang on to existence in relatively remote areas, nor is it a long time for 100+ birds (if Tanner's estimate was waaaay off) to go unphotographed. What we have over those 60 years are possible IBWO cavities, possible sounds/recordings, possible foraging signs, and many purported sightings, and all we lack is an agreed-upon photograph --- and THIS is the evidence skeptics regard as a slam-dunk for proclaiming extinction --- quite remarkable!! (and potentially, quite shortsighted).
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In other Web news... they're not just for hunters:

http://www.fws.gov/duckstamps/Info/Stamps/stampinfo.htm

Duck Stamps can be purchased by anyone, and the proceeds go toward conserving/maintaining wetlands habitat including areas well-suited to the Ivory-billed Woodpecker. The Stamps get you free admission to many Wildlife Refuges and represent a good cause even if you don't actively bird or hunt. If not already familiar with them check out the above site for more info.
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