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Mark Michaels has newly-posted a retrospective of Ivory-bill sightings (and other info/commentary) from 1944 - 2003 at the Project Coyote site:
http://projectcoyoteibwo.com/2015/02/13/948/
Nice job Mark. Makes for a good adjunct-read to Chuck Hunter's historical review of the evidence in Appendix E of the "Recovery Plan For the Ivory-billed Woodpecker" from USFWS (starting on pg. 66):
http://www.fws.gov/ivorybill/pdf/IBWRecoveryPlan2010.pdf
And I agree with most of Mark's points, especially regarding scantiness of valid information, certain flawed analyses and assumptions, and the circularity of various arguments (though he's probably more favorably-disposed towards certain bits of evidence than I am). The bottom line for me still remains:
There have been a significant, even if rare, number of sightings over time (not always highly-publicized) from individuals (birders, wildlife officers, park rangers, etc.) who should be able to reliably recognize an IBWO apart from similar species. To which skeptics will frustratedly opine, "Yeah, yeah, yeah, so get a #$%@*^%!!! photo!" ...and I DO sympathize with them and several of their arguments. But the possible habitat of the IBWO is remote, dense, and neither visited by birders in great numbers nor with great frequency. My only excuse for the lack of a definitive photo by now, even when areas producing credible claims are scoured, is, as previously noted, the combination of the species' sparseness with a lifestyle, I think, spent mostly in the upper tree canopies, out of easy or good view. So while hope fades, it is far from gone. And while I wish I had enough faith in the practice of science to draw a conclusion of extinction based on the evidence so far collected... I don't.
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6 comments:
Thanks!
At what point does the lack of any evidence mean something for you?
Hi David, several things:
1) First, it's a sliding scale, I don't suddenly go from believing a species exists to believing it's extinct, but rather my confidence level simply diminishes over time (so where I felt 95+% confident of IBWO survival several years ago, I might be down to 50% or less in a few more years).
2) "Evidence" is a very subjective term... I accept several sightings over the decades, and also the Luneau video as good evidence for the species, obviously others do not and have in fact, by their own admission, raised the level of necessary evidence quite high, to the level of "extraordinary evidence" -- "extraordinary claims require extraordinary evidence" (customary evidence no longer applies). Cornell (and for that matter Mike Collins) feel they have plenty of evidence that the species was around a few years ago.
3) As the other old aphorism runs (and demonstrated virtually every year by the discovery of new species, including so-called "extinct" species), "absence of evidence (by itself) is not evidence of absence."
But if you want a very rough rule-of-thumb to go by, I've always used the century-mark as a general guide: i.e. when a species hasn't been observed/confirmed for 100 years than I may begin to feel comfortable with the designation "extinct." If you regard the 1940s as the last confirmation of the IBWO than it takes me to around 2040 to feel some certainty of extinction (on the one hand, the sheer amount of effort put into finding this species might allow an earlier decision; on the other hand the repeated sightings from credible people every decade could extend the 2040 date).
4) Lastly, this species has been repeatedly called "extinct" in the past, only to be re-discovered each and every time -- that is a damning statement of the prior weakness of ornithology and conservation; it's a mistake I'm just not willing to risk yet again.
"absence of evidence (by itself) is not evidence of absence."
Yes it is. It's how we know species are extinct.
People are so arrogant in asserting what they think they know. As cyberthrush noted there is plenty of evidence, albeit controversial by some standards. These aren't scientific standards, however, as evidence such as Mike Collins' data has yet to even receive a proper response. Meanwhile, folks like the poster above continue to religiously check this site and share their irrelevant declarations for some reason.
I check because I keep hoping one of y'all will find the bird. I was very hopeful, ten years ago. I thought, how could Cornell possibly be wrong?
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