Monday, November 13, 2006

Redefining Extinction

In response to this post at Ivory-bills LiVE!!, which noted an alleged "paucity of evidence for extinction" of the Ivory-billed Woodpecker, I posed this question to cyberthrush:
I’m curious, cyberthrush. What would you consider to be compelling evidence for 'extinction' of the IBWO (or any other creature, for that matter)?
Here’s an excerpt of cyberthrush‘s response:
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 it’s 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 . . . .
Cyberthrush’s purported history of "credible reports" of Ivory-bills at least every five years is stunningly at odds with that generally accepted by scientists.

For example, from the Fish and Wildlife Service’s "official" history of the IBWO (also see here ([.pdf]), we learn that:
Following the inevitable decline of [virgin] forests [in the southeastern U.S. following the onset of World War II], the last confirmed ivory bill sighting was in 1944 [when artist Don Eckelberry sketched the last known bird in the Singer Tract].

For [the next] 60 years there were sporadic ivory bill sightings, none confirmed [until the 2004 sightings and video from the White River of Arkansas, which have been disputed by some experts].
In the end, I guess your willingness to accept reported sightings of Ivory-bills in the 60 years following the last universally accepted photograph depends on how you define "credible" and "confirmed" and how much you want to believe in your heart that Ivory-bills continue to exist.

In my opinion, the "compelling evidence" pointing to extinction of the Ivory-billed Woodpecker includes the following: (1) lack of physical evidence of any kind (carcasses, feathers, eggshells, or droppings that can be analyzed for DNA), (2) lack of indisputable photographic or video evidence, (3) lack of indisputable vocal evidence, (4) no indisputable evidence of breeding activity, and (5) no sight records reviewed and accepted by bird record committees of any State.

6 Comments:

Blogger Bill Pulliam said...

The heart of the matter here, John, is that while there may be no indisputable evidence for survival, it is not possible for there to be indisputable evidence for extinction because of that whole proving-a-negative thing. Thus, either conclusion remains a judgement call, and anyone who proclaims either position as fact is basing this statement on some measure of belief.

Extinction was "officially" proclaimed (pre-2004) by the ABA, Sibley, and Kaufman, none of whom are actually "official" to anyone but the birding community. The real "official" scientific and governmental bodies (AOU, USFWS) remained uncommitted on the extinction question.

November 13, 2006 10:57 PM  
Blogger Bill Pulliam said...

John, let me ask you this:

Are you confident enough in your beliefs that, if you had the power to do so, you would call for an end to all search efforts, the dissolution of the recovery team, and the termination of all IBWO-related funding? Would you aggressively discourage all NGOs and private individuals from allocating any resources to IBWO-related activities?

November 14, 2006 10:35 AM  
Blogger John L. Trapp said...

Bill Pulliam said, The heart of the matter here, John . . .

I was initially prompted to pose my question to cyberthrush exactly because of "that whole proving-a-negative thing," but didn't say that in so many words, either in my question to cyberthrush or in my follow-up blog entry.

According to the Wikipedia article on the IBWO, no less an authority than the august IUCN declared the Ivory-bill officially "extinct" in 1994. "This assessment was later [in 2005] altered to 'critically endangered' on the grounds that the species could still be extant."

November 14, 2006 6:52 PM  
Blogger John L. Trapp said...

Bill Pulliam asked, Are you confident enough in your beliefs . . .

Based on the scanty evidence produced to date, I don't believe that American taxpayers are being well-served by the Federal and State dollars being spent on this project.

I would not "aggressively discourage all NGOs and private individuals from allocating" their resources on a search for Ivory-bills. That's what private money is for. If NGOs can find wealthy donors to bankroll such a project (as in the Pearl River search funded by ZEISS), more power to them.

November 14, 2006 7:11 PM  
Anonymous Anonymous said...

Let's face it. If there was nothing else left to do in the world, then looking for the IBWO would still be stupid.

It's extinct, Bill. Get over it. Get over your psuedo-scientific nonsense.

November 16, 2006 2:43 PM  
Blogger Bill Pulliam said...

Ya know, I try to stick to the point and avoid insulting language when posting here, saving the mud for the mudpits. Fat lot of good it seems to accomplish.

November 17, 2006 4:53 PM  

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