Wednesday, December 06, 2006

-- Of Ivory-bills and Vegans --


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Over the years I've known several people who became vegetarians or even vegans after eating and enjoying meat for 30-40 years and even thinking meat was necessary for their health. In actuality, many things that we think of as necessary in life are in fact little more than ingrained preferences, that we can easily live without.

In biology much is made of the notion of specialist versus generalist species. But this is just a human construct and a false black-and-white dichotomy. ALL creatures are specialists in some sense, it is only a matter of degrees. Indeed, pigeons and starlings may in fact be "specialists" just as much as Ivory-bills, even if we humans haven't yet perceived or categorized their particular specializations.

Following Tanner, writers came to blindly repeat the notion that Ivory-bills REQUIRED certain foods, certain size trees, certain amount of space for survival, but without evidence to support such definitive claims. No amount of repetition by itself validates such statements. Tanner showed only that a pitifully small sampling of Ivory-bills preferred certain foods... when available, preferred certain trees... when available, and utilized a certain number of square miles... when available. That Ivory-bills could NOT survive without bark beetle larvae, without large first-growth trees, and on less than 6 square miles simply has never been shown, and is actually quite a leap of logic (Ivory-bills, being 15-20% larger than Pileateds, could likely make do with trees 20% larger than those used by Pileateds, and such trees are plentiful.) To truly know the needs/requirements of a creature one must know its physiology and cognition --- behavioral cues/observations by themselves are not enough to base such firm conclusions, and yet that is principally what we have for the Ivory-bill (there are possible physiological reasons why the IBWO species might be unable to survive without beetle larvae, but these are rarely discussed).

Maybe time will show that Tanner, or his interpreters, got it right from the start, but I'm still waiting for the evidence, not mere regurgitation, that would validate that. And in the meantime, 1000's of acres of land that do meet Tanner's requirements await searching.
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