Today, re-running an entry I posted here over 10 years ago!
Recently Mark Michaels linked to an older Geoff Hill review of a Noel Snyder monograph where he [Snyder] argues that hunting played a much greater role in the demise of the Ivory-bill than generally recognized (definitely worth reading):
http://www.bioone.org/doi/pdf/10.1525/cond.2008.8658
I made the same essential argument here a decade ago (in a different post), and to give people their due, Mike Collins made a similar argument as far back as 1997. At the time I utilized this quote from T. Gilbert Pearson, one of the foremost naturalists of his day:
"The reduction in abundance of this species [IBWOs] is due most probably to persecution by man, as the species has been shot relentlessly without particular cause except curiosity and a desire for the feathers or beaks." (National Geographic Magazine, April 1933)The reason I bring it up now is to again reiterate my belief that very little that is concluded in the literature about the behavior or needs of Ivory-billed Woodpeckers, based on Tanner's work, can be assumed true for currently surviving IBWOs. I don't even believe Tanner's conclusions for the Singer Tract birds automatically generalizes to any Ivory-bills that then survived in Texas, Florida, South Carolina, or elsewhere -- we just don't know -- the sample size, studied largely by a lone individual, is simply too small to be very meaningful (p.s., I DON'T blame Tanner for this; it is common practice in field biology to draw over-reaching conclusions from inadequate sample-sizes -- nor do I mean to imply that the historical studies lack any merit, but only that they must be viewed cautiously, instead of as gospel fact).
Anyway, here's what I wrote, more generally, back in 2005, in the post "Science and Sample Size":
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One of the fundamental tenets of science methodology concerns having adequate sample sizes from which to draw conclusions/generalizations. In the years since James Tanner's dissertation on the Ivory-bill (based on but a handful of birds), notions that Tanner himself often recognized as tentative became hardened into unchallenged dictums without a good basis for doing so. There is in fact little that can be stated with certainty about the Ivory-bill's diet, behavior, habits, or requirements for survival, even though such statements are rife in the literature. (If one were to intensely study a dozen people and then write a report generalizing to the entire human species the weakness would be readily apparent.) This is all especially true given that any Ivory-bills still around today may in fact have survived specifically BECAUSE they came from individuals with significantly DIFFERENT characteristics/behavioral traits from their brethren, which increased survivability for themselves and their offspring. At least Tanner got it right at the end of his original introduction:
"The chief difficulty of the study has been that of drawing conclusions from relatively few observations... My own observations of the birds have been entirely confined to a few individuals in one part of Louisiana... the conclusions drawn from them will not necessarily apply to the species as it once was nor to individuals living in other areas. The difficulty of finding the birds, even when their whereabouts was known, also limited the number of observations. Especially was this true in the non-breeding season. With these considerations in mind, one must draw conclusions carefully and with reservations." (italics added)The problem with our knowledge of Ivory-bills is not simply how little we know, but rather how much we think we know that might just be utterly wrong for any birds remaining today...
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