Below is a photo by Martjan Lammertink, "the world expert on large woodpeckers," of a tree which "has bark peeled in typical Ivory-billed fashion. The birds use their large, chisel-like bills to pry the bark away and get at the beetle grubs underneath." [Source: www.birds.cornell.edu/Publications/LivingBird/Summer2005/press_conference.html .]
Julie Zickefoose relates her conversation with ornithologist Don Eckelberry, who had observed living Campephilus principalis in 1944: "I may be the last ornithologist to have seen them in the States... It was in April, 1944. This is northeast Louisiana, the Tensas River bottom... It isn't really a woodpecker; it's a bark peeler. When she was peeling bark, her head was turned back to the side and went under the bark. Down at the base of the tree you'd find big strips of bark, not little chips. She'd start and hitch down and keep peeling it down and eating the grubs in the cambium layer, between the bark and the wood." [Source: www.juliezickefoose.com/writing/ibw.php?id=4]
The following image shows the "chisel-like" bill of Campephilus principalis:
[Source: Wikipedia entry for the Ivory-billed Woodpecker.]
Julie goes on to say: "It's clearer to me now that the chances of these big tree-peelers hanging on in the face of full-scale forest exploitation are slim. While ivorybills could use their great chisels to advantage in digging nest cavities, they were not, by nature, true excavators, as are pileated woodpeckers. The smaller birds do peel bark, but they also dig deeply into the wood, from living to decades-dead, finding a great variety of insect food along the way. Pileated woodpeckers inhabit a wider niche; they're closer to being generalists in their food requirements and foraging strategies. Even in the Singer Tract, Tanner estimated a density of 36 pileateds inhabiting the foraging territory of a single ivorybill!"
It is becoming clearer to me that any searcher for Campephilus principalis must be familiar with the signs of bark peeling mentioned above. Until now, I have mainly looked for large tracts of forest that include many dead and dying trees. I recently read somewhere (I will attribute it when I recall) that Ivory Bill needs, more specifically, trees that are either dead or within a year or two of dying. But the telltale sign is the peeling. Now I must train my eyes to look for it.
EDIT: It would seem that Audubon's illustration depicts this behavior, with the object of the bark-peeling -- a wood-boring beetle -- the center of attention:
EDIT: Here I must give mention to my suspicions regarding wildlife populations in the 81,000-acre Singer Tract (compare to the Leaf River Wildlife Management Area, at 42,000 acres). From what little I have read of it during Tanner's stay (I have not yet read Tanner's account, but it is coming), the place was teeming with wildlife of all kinds -- it had every species there that would have also been there during Audubon's time, excepting only the Passenger Pigeon and Carolina Parakeet (Paroquet). Wolves, bears, and panther were fairly common. But considering that the Singer Tract was an island of primeval wilderness in a region largely logged over, it may have become a last refuge for many of the area's species of birds and mammals: populations, therefore, may have become artificially inflated due to human activity outside the bounds of the Tract in the previous decades, as the wildlife with mobility fled logged-over areas for the relative safety of the Singer. Thus it is possible, for example, that while Tanner's estimation of 36 pileateds for every ivory-bill might have been accurate (as accurate as tidy mathematics may be in sprawling, untidy Nature), the number may only serve as an indicator of the unnaturally high animal and bird populations of the Singer Tract as a whole. This aspect, at least, of Tanner's observations may make them unreliable as a guide to present-day population dynamics of Dryocopus pileatus, and of Ivory Bill.
Julie Zickefoose relates her conversation with ornithologist Don Eckelberry, who had observed living Campephilus principalis in 1944: "I may be the last ornithologist to have seen them in the States... It was in April, 1944. This is northeast Louisiana, the Tensas River bottom... It isn't really a woodpecker; it's a bark peeler. When she was peeling bark, her head was turned back to the side and went under the bark. Down at the base of the tree you'd find big strips of bark, not little chips. She'd start and hitch down and keep peeling it down and eating the grubs in the cambium layer, between the bark and the wood." [Source: www.juliezickefoose.com/writing/ibw.php?id=4]
The following image shows the "chisel-like" bill of Campephilus principalis:
[Source: Wikipedia entry for the Ivory-billed Woodpecker.]
Julie goes on to say: "It's clearer to me now that the chances of these big tree-peelers hanging on in the face of full-scale forest exploitation are slim. While ivorybills could use their great chisels to advantage in digging nest cavities, they were not, by nature, true excavators, as are pileated woodpeckers. The smaller birds do peel bark, but they also dig deeply into the wood, from living to decades-dead, finding a great variety of insect food along the way. Pileated woodpeckers inhabit a wider niche; they're closer to being generalists in their food requirements and foraging strategies. Even in the Singer Tract, Tanner estimated a density of 36 pileateds inhabiting the foraging territory of a single ivorybill!"
It is becoming clearer to me that any searcher for Campephilus principalis must be familiar with the signs of bark peeling mentioned above. Until now, I have mainly looked for large tracts of forest that include many dead and dying trees. I recently read somewhere (I will attribute it when I recall) that Ivory Bill needs, more specifically, trees that are either dead or within a year or two of dying. But the telltale sign is the peeling. Now I must train my eyes to look for it.
EDIT: It would seem that Audubon's illustration depicts this behavior, with the object of the bark-peeling -- a wood-boring beetle -- the center of attention:
EDIT: Here I must give mention to my suspicions regarding wildlife populations in the 81,000-acre Singer Tract (compare to the Leaf River Wildlife Management Area, at 42,000 acres). From what little I have read of it during Tanner's stay (I have not yet read Tanner's account, but it is coming), the place was teeming with wildlife of all kinds -- it had every species there that would have also been there during Audubon's time, excepting only the Passenger Pigeon and Carolina Parakeet (Paroquet). Wolves, bears, and panther were fairly common. But considering that the Singer Tract was an island of primeval wilderness in a region largely logged over, it may have become a last refuge for many of the area's species of birds and mammals: populations, therefore, may have become artificially inflated due to human activity outside the bounds of the Tract in the previous decades, as the wildlife with mobility fled logged-over areas for the relative safety of the Singer. Thus it is possible, for example, that while Tanner's estimation of 36 pileateds for every ivory-bill might have been accurate (as accurate as tidy mathematics may be in sprawling, untidy Nature), the number may only serve as an indicator of the unnaturally high animal and bird populations of the Singer Tract as a whole. This aspect, at least, of Tanner's observations may make them unreliable as a guide to present-day population dynamics of Dryocopus pileatus, and of Ivory Bill.
