Friday, November 10, 2006

-- Auburn Update... & Common Question --

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First, this update on the Auburn group's plans for the coming search season:

http://www.auburn.edu/academic/science_math/cosam/departments/biology/faculty/webpages/hill/ivorybill/Updates.html


Secondly,
John Trapp of Birdstuff blog recently sent me a question I hear a lot:
"I'm curious, cyberthrush. What would you consider to be compelling evidence for extinction" of the IBWO (or any other creature for that matter)?"
This is a simple, basic matter. "Extinction" is a very significant (maybe even extraordinary) claim and thusly requires very strong evidence. Theoretically, one should thoroughly search all likely potential habitat and find no sign of a creature in order to declare it extinct (is that so hard to comprehend?) This is occasionally possible for creatures residing on islands or very limited geography, but for most creatures, including the IBWO it is not very practical and is never fully accomplished. Thus, we usually accept some passage of time without reports as adequate. But too many creatures have been "re-discovered" after 50-60 years' absence. ~100 years with few or no credible reports is a far safer, scientifically-sounder criteria. If the Ivory-bill had truly gone even 60 years with no credible reports it would be discouraging, but it hasn't. There have been credible reports of Ivory-bills throughout its history --- since the 30's the species has probably never gone even five years without a credible report, i.e. a report that couldn't be quickly dismissed upon interrogation (though most of these reports aren't well publicized or written about unless there was significant follow-up). The fact that IBWOs, if extant, likely reside in difficult and sparsely (if ever) birded areas means even more caution is necessary in passing judgment.

As indicated in the previous post, if serious searches continue in several areas for the next few years, and 50 years pass with no credible reports from elsewhere, then I would find that, combined with the previous history, compelling evidence for the likelihood (much greater than 50/50 chance) of IBWO extinction. It's really pretty simple: to presume something extinct, look for it thoroughly, extensively, and without success, and/or let a truly significant amount of time pass --- I think that's a pretty minimal requirement, both scientifically and common-sensically. A declaration of "extinction" is essentially a declaration of (species) "death" --- how many of you would feel fine being declared dead and nailed inside a coffin based on the sorts of evidence (basically differences of opinion) thus far presented....

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