[Nancy Tanner] brought a DVD which had clips of ivory-bills at the nest--a male and female. It was stunning to see the photo stills we all know so well, moving and even calling--the male's bill opening, that strange tooting call being given. They are shiny, shiny birds, so strong and vigorous. They looked nervous, and Nancy said they were--nervous about the grinding camera and the crew below their nest. Imagine!
Monday
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The abstract at the end of this cmment from the large woodpecker symposium can be found at http://nature.org/ivorybill/files/symposium_abstract.pdf
Snyder has some interesting ideas. It isn't mentioned in this abstract, but I've heard that during his talk, he brought up the point that the remaining Ivory-billeds in diminishing populations, such as Florida (according to Wayne's accounts, I believe) and Cuba, were in fact more wary.
The role of human depredations in the decline of the Ivory-billed Woodpecker
(Campephilus principalis)
Noel F.R. Snyder, Portal, Arizona, nfrs16426@vtc.net
In virtually all modern accounts, the endangerment of the Ivory-billed Woodpecker has been attributed
mainly to (1) extreme foraging specialization, leading to a crucial dependency of individuals on vast areas
of pristine woodlands to obtain sufficient food, and (2) the logging of nearly all virgin forests in the
species' original range. However, rigorously persuasive evidence for the ivory-bill being an extreme
foraging specialist appears to be lacking, and the numerous reports of early abundance of the species
across its original range are difficult to reconcile with a dependency of individuals on vast areas of mature
forests. Although the ivory-bill did exhibit sparse populations and a frequent close association with
remnant virgin forests as it approached extinction, these characteristics may have been due mainly to
factors other than food stress. In particular, direct human depredations may have been more important that
habitat modification and food scarcity in producing the species' decline. The loss of certain Florida
populations to zealous specimen collecting has long been acknowledged. But in addition, there are other
populations for which evidence plausibly suggests extirpation mainly due to subsistence, curiosity, and
sport killings. The high vulnerability of the ivory-bill to human depredations was often noted in historical
accounts, and no substantial regions are known that were free of such threats. In many regions major
ivory-bill declines clearly took place before logging operations were initiated, suggesting that habitat
destruction was at most a secondary stress, whatever the primary stress may have been. Logging must
surely have greatly lowered the carrying capacity of most woodlands for the species, but not necessarily
to the point where food supplies were inadequate to support any ivory-bills. Instead, logging's most
significant detrimental role may have been the facilitation of human depredations on remnant populations,
especially by providing much improved access to formerly remote regions, a role increasingly recognized
as crucial in the current disappearance of vulnerable wildlife species from tropical forests around the
world.
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