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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






Tuesday, October 16, 2007

 

-- Extinction --

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I get emails....

...repeatedly, asking when, if ever, I'd consider the Ivory-bill extinct, so we'll cover this again:

First, it must be said that contrary to what sometimes is stated on the Web, Ivory-billed Woodpeckers were never and have never been declared extinct by any official Governmental agency. Only individuals and a few impatient non-governmental groups over the years took the liberty of labeling the species "extinct."

Now, the Moa and Dodo, yeah probably extinct --- I'd certainly be hugely surprised if any evidence to the contrary arose. On-the-other-hand, Passenger Pigeon and Carolina Parakeet, while certainly most likely also extinct, I would not be completely surprised if evidence to the contrary arose in either case, even if unexpected.

Declaring a species extinct is a serious matter, never to be done lightly, and can logically be based only on one of two things:

1. A truly lengthy lapse of time with no credible sightings for the species. And for a species with an extensive prior range like the Ivory-bill's, 60 years is not a long enough time even with no sightings, and certainly not enough time
when a continuous string of reports is involved (as further borne out by the number of species re-discovered after a 50-60 year absence, or even after 100 years).

or,

2. A thorough, systematic search of the remaining habitat that might harbor a species reveals no indication for its presence --- this can sometimes be accomplished for species with very small ranges (such as a single island), but again, in the case of the Ivory-bill it hasn't, and realistically can't, be accomplished.

What is necessary then in the case of the Ivory-bill is as thorough a search as practical of remaining habitat (which is finally underway) combined with a lengthy passage of time with no credible sightings. This may eventually come to pass, but it hasn't been achieved in the previous 60 years. Those who think it has, vastly overrate the precision of human foot-searches.

Instead, skeptics repeatedly equate a
'failure to confirm' a claim, to evidence that the claim is false, when it is nothing of the sort. Indeed, a lot of good science would be tossed aside if failures to confirm were all it took to falsify.
Moreover, skeptics assume that if 90% of IBWO claims are quickly demonstrated as mis-IDs, wishful thinking, illusions, mutated Pileateds, and the like, than ALL such claims must be assumed as such. But one cannot simply dismiss a sighting as 'mistaken' without specifying inaccuracies or falsehoods in the claim; nor does the invention of alternative explanations allow for the automatic dismissal of a stated claim. Generalizing from a set of specific cases (mistaken IDs) to ALL cases, instead of evaluating each one independently, is simply sloppy science, especially when involving different people in different places at different times. The fallacy of over-generalization is risky in all of science, but especially so here, where confirmation of but a single recent Ivory-bill report validates the species' existence for the entire 60 years prior, regardless of how many other claims prove false.

Over the last 40 years, and well before any news from the Big Woods and Choctawhatchee, my personal confidence in Ivory-bill existence ranged anywhere from about 85% to 98% probability --- and nothing that has happened in the last 3 years much changes that overall range for me.
But yes, if time passes with increased and wider searches, and still no photo, and fewer and fewer credible reports arising, then that percentage might easily fall well below the critical 50%. But, it isn't likely to reach the certainty level that so many skeptics already preach.

Certainty in life is rare and boring. Probabilities are the very stuff of life --- what make it interesting and worthwhile. And in the realm of the Ivory-bill, we can disagree over what those probabilities are, but in the end, probabilities and not certainty, are what we have to work with. For now, I continue to put my trust in the actual on-site reports of certain individuals who's knowledge and experience is such that they ought to know what they witnessed with their own eyes, and not in the conjectures, speculation, and denigrations cast out by others, often from afar.

....in the meantime, on the off-chance you think you spot a Dodo crossing your backyard... well, DON'T notify me.
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