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.