(Apologies to BirdForum readers who've already seen me discuss this...)
I've argued for several years that hunting may have been a more important factor, and habitat loss a less important factor, in the Ivory-bill's demise than the standard literature portrays (at least I can find no evidence to refute the possibility), but I thought I was the only one making such a case. Thus, I was pleasantly surprised when one of my readers sent along a 1933 article on the IBWO by no less than T. Gilbert Pearson which ends with this conclusion:
"The reduction in abundance of this species 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)This is written almost a decade before Tanner published his conclusions which would become unchallenged gospel. The point once again is that most everything we commonly believe today about Ivory-bills stems from one man's study. If he got it 100% right, there'd be no problem... but what are the chances of that. There's simply too much we don't and can't know with certainty. Or putting it a different way, it's not even what we don't know that creates the biggest problems, it's what we think we DO know that's simply wrong that generates the greatest errors. The point is, birds DIE when they are shot; they DON'T die when their habitat is destroyed -- they fly off looking for new habitat -- they may die later or fail to reproduce due to lack of habitat, but there is NO IMMEDIATE effect as there is with hunting; the effect of habitat loss is drawn out and indirect; still very powerful in the long term, but very different from hunting/collecting in the shorter term.
To whatever degree hunting played a major role in the IBWO's decline, its cessation gave the remaining IBWOs the opportunity to stabilize and recover their population -- I can't stress this point enough. Even Tanner concluded that in many specific locales after habitat loss had its effect, it was hunting/collecting that really drove the final nails into the IBWO's coffin. It is also possible that other factors of disease, in-breeding, and predation, could have played greater roles in the decline of certain IBWO populations than realized. In short, the incessant chant of "habitat-loss, habitat-loss, habitat-loss" may be convenient, but way too simplistic (although I don't want this in any way taken as belittling the overall drastic consequences of habitat destruction around the globe today).
--- As a sidenote I just recently learned that writer/ornithologist Noel F.R. Snyder is currently completing a paper on this very subject of the causes of the Ivory-bill's demise. Something to look forward to.
-----------------------------------------------------------------------------------
1 comment:
An abstract of Snyder's presentation on this subject at the Ecology of Large Woodpecker Symposium is available here: http://www.nature.org/ivorybill/files/symposium_abstract.pdf#search=%22large%20woodpecker%20symposium%20brinkley%20abstracts%22
Post a Comment