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Treatise #178 ;-) :
The seeming shyness and scarcity of sound from the Ivory-billed Woodpecker is often a subject of discontent among skeptical participants in this debate. At his blog, Jim McCormac (like others) worries over differences between the Ivory-bill and its Central American cousin, the Pale-billed Woodpecker, here:
http://jimmccormac.blogspot.com/2008/03/ivory-billeds-little-brother.html
But comparing behaviors of one species in one locale with a remnant population of a different species in an entirely different locale is always fraught with uncertainty. Moreover, what I believe commentators continually underestimate is the combined effects of natural selection, rarity, and large spaces. Species that come under heavy hunting pressure, over time, will naturally select for those individuals most wary of humans, leading to future generations that purposely avoid humans, as the wariest individuals survive and pass on their genes. When those future progeny are very scarce, inhabiting immense areas, and able to cover wide spaces, the scarcity of sound (and sightings for that matter) is not hard to account for.
Most readers have likely heard crows with some frequency in their area, but what if one could somehow distinguish the sounds of individual crows, and instead of simply listening for the presence of crows I asked you to listen for 'crow #12' and 'crow #38' ? --- that is more akin to the dilemma facing IBWO searchers listening for paltry few birds over wide distances. Some will argue that the Ivory-bill can't both be that scarce, yet also populous enough to be reproductively viable. But animals seeking mates do routinely find one another over huge distances, and a single IBWO pair could produce a couple dozen offspring in a lifetime, easily off-setting other losses and failures, and permitting a stable-state population to exist at low levels for decades across the southeast.
Purported Ivory-bill sounds and sightings will in fact likely continue to trickle in at a slow rate (whether any will be universally convincing or accompanied by a photograph/video, only time will tell) --- were they coming in at a far greater rate then, yes, one might more understandably expect definitive evidence of the species by now; but coming in at the rate they are, the difficulty of conclusive evidence is not so impossibly hard to fathom.
Somewhere in a comment below I wrote that "initial assumptions" are often the Achilles heel of science. It is indeed initial, ingrained, blind, and unproven assumptions that too many skeptics are married to (and don't even recognize having), that in large part this entire debate turns on. Having read a lot of the history and methods of the physical sciences, I'm not willing to be driven by initial assumptions; on-the-other-hand, I find that Ivory-bill skeptics, and frankly, biologists in general, are usually stubbornly unwilling to lay them aside.
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1 comment:
While we are on the subject of "shyness and scarcity" I am wondering if Tom Nelson's website might be a fitting analogy for the lack of IBWO audio. People used to post on Tom's blog all the time when it dealt with the IBWO. Now it could be called the "No Comment" blog since it mainly consists of Tom linking to whatever he can find that, in his eyes, demonstrates the stupidity and/or greed of those who are observing climate change, with essentially no one providing comments. One could assume that the large population of visitors to the blog are still present but left speechless by the change of topic - or one might think that the population of visitors to the site is now so low as to almost be extinct. I happen to believe the latter and assume the one or two people who comment there now are not likely to maintain their population very far into the future.
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