"....The truth is out there."
-- Dr. Jerome Jackson, 2002 (... & Agent Fox Mulder)
“There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.”
"All truth passes through 3 stages: First it is ridiculed. Second, it is violently opposed. Third, it is accepted as self-evident."
-- Arthur Schopenhauer
Thursday, February 19, 2009
-- IBWO Researchers Forum --
Those who assiduously follow all-things-Ivorybill likely already know that one of the recent topics of discussion over at IBWO Researchers Forum has been potential drumming (or tapping) patterns for the Ivory-bill possibly heard in the field by searchers or recorded in Cornell's original (and only confirmed) soundtrack of Ivory-bills from the Singer Tract (1930s), available here:
Bill Pulliam weighs in with his thoughts on the matter here.
I'm all for pursuing all leads and forms of analysis. My only precaution being that the Cornell recording represents a single example from a miniscule sample of birds at one isolated location 70 years ago, and I'm not willing to assume that the tape is NECESSARILY technically representative of remnant birds left today in other parts of the country, separated by several generations from the birds recorded... BUT, that tape is all we got, so of course, by all means use it (and I think there is reason to believe that rapping or drumming patterns would change less over time than "kent" sounds might... still, very small sampling size). So have at it.
The other focus of attention lately over at the IBWO Forum has been a recent possible (brief) sighting claim for 2 Ivorybills in the Congaree (S.C.) by one of the independent searchers there. The Cornell search team is scheduled to be in S.C. in mid-March anyway; we'll see if the latest claim gets them there any sooner. S.C. remains near the top of everyone's list for best potential IBWO habitat in the entire Southeast; whether there are birds there to utilize it, time will tell.
Something we do know: that the Ivorybill had a loud fast double rap, apparently similar to that of the Pale-billed, that is not heard in this recording. A pair of Pale-billeds under similar circumstances would have probably been double-rapping at each other almost continuously; from this we might conclude that though the Ivorybill had a similar double rap, it might not have actually used it nearly as often as some other Campephilus species and this slower rapping might be the primary contact call, at least between members of a pair. This is significant, especially since the fast double rap has been a primary focus of contemporary audio searches for the bird. It's a hypothesis, based on a small sample, but it's based on simple observations and hard evidence.
But if the bird has become significantly warier, doesn't it seem likely it could also have modified other behaviors as well?
Most of the accounts of noisiness seem to pertain to vocalizations, and I would think that there's a difference between calling and drumming or rapping. I suspect that selection pressure would be greater with regard to the former than it would be with regard to the latter, especially (apparently) since no one has associated this rapping pattern with Ivory-bills until now. This take is purely intuitive.
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