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IVORY-BILLS  LiVE???!  ...

=> THE blog devoted to news and commentary on the most iconic bird in American ornithology, the Ivory-billed Woodpecker (IBWO)... and... sometimes other schtuff.
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"....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.”

-- Hamlet

"All truth passes through 3 stages: First it is ridiculed. Second, it is violently opposed. Third, it is accepted as self-evident."

-- Arthur Schopenhauer






Monday, May 19, 2008

 

-- Tanner Redux --

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While awaiting summary info from this season's searches, may be worth reviewing some old quotes from James Tanner's 1942 monograph on the species (all italics added):

"The chief difficulty of the study has been that of drawing conclusions from relatively few observations, necessary because of the extreme scarcity of the bird. 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."

"The dominance of cypress in the bird's [Florida] habitat is a condition not found outside of the Florida region. Another difference is that Ivory-bills in Florida frequently fed in the pine woods bordering the swamps, something that has never been recorded in the region of the Mississippi Delta and only rarely elsewhere."

"There is no one type of forest that is the habitat of the Ivory-billed Woodpecker; it varies greatly in different sections of the bird's range."

"Hunting for localities where Ivory-bills were, and in those localities trying to find the birds, was like searching for an animated needle in a haystack."

"Winter and early spring are the only good seasons for investigating Ivory-bill habitats. Leaves are then off the trees, allowing good visibility and hearing, the birds are quite active and noisy, and the cooler weather makes work in the woods pleasant. Work in the summer is practically a waste of time because of the dense vegetation, silent birds, and depressing heat."

"Ivory-bill sign shows as bare places on recently dead limbs and trees, where the bark has been scaled off clean for a considerable extent. Pileateds do some scaling too, but it is usually confined to smaller limbs and to those longer dead. Freshness of sign can be judged by any appearance of weathering, which will soon turn bare wood a grayish color. Extensive scaling of the bark from a tree which has died so recently that the bark is still tight, with a brownish or reddish color to the exposed wood showing that the work is fresh, is one good indication of the presence of Ivory-bills."

"All the Ivory-bills that I have ever seen I located first by hearing them call and then going to them."

"Considering the maximum abundance of the Ivory-bill to have been one pair per six square miles, of the Pileated to be six pairs per one square mile, and of the Red-bellied to be twenty-one pairs per one square mile, the relative abundance of these birds would be one Ivory-bill to thirty-six Pileated to 126 Red-bellied Woodpeckers."

"Considering all the evidence, I believe that Ivory-bills were not sedentary birds, but sometimes wandered considerable distances....
Furthermore, the Ivory-bill is well adapted to traveling for long distances. It is a strong flier with a fast flight for a woodpecker, and individuals have been observed feeding over several square miles."

"The Ivory-bill's habit of feeding and living almost its whole life in and near the tops of trees makes it very unlikely that any mammal could prey on one."

"The flight of the Ivory-bill... is strong and usually direct, with steady wing-beats. They can take flight quickly either from a perch or from a hole, springing into the air with very little descent before getting up to speed. They often fly above the tree tops, dodging the trees with very little deviation from their course. In the thick woods it is ordinarily difficult to tell how far the Ivory-bills fly, but I am quite sure that their flight is often extended for half a mile or more... They end their flights with a quick upward swoop and a few braking wing-beats, usually landing on a vertical tree trunk or slightly inclined limb."

"The wing-feathers of Ivory-bills are stiff and hard, thus making their flight noisy. In the initial flight, when the wings are beaten particularly hard, they make quite a loud, wooden, fluttering sound, so much so that I often nicknamed the birds 'wooden-wings'; it is the loudest wing-sound I have ever heard from any bird of that size excepting the grouse. At times when the birds happened to swoop past me, I heard a pronounced swishing whistle."

"The notes of the nuthatches are the only bird calls I know that sound like the voice of an Ivory-bill; the Ivory-bill's calls are much longer and pitched higher than the calls of a White-breasted Nuthatch, are more in the range of a Red-breasted Nuthatch."

"Ivory-bills are not social or gregarious birds; they have apparently always lived in solitary pairs, and as long as the birds can mate, they are capable of reproduction and increase. With small numbers, inbreeding could occur, but there is no evidence that this would be harmful. Large numbers are not necessary for the continued existence of the Ivory-bill. Even though it would be better and more promising if the birds were more abundant, still they are not, and if we are to make any attempt to save the species, we must be satisfied in starting with a few individuals."

--- May it be so. . . .
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Comments:
Thanks for sharing this compilation; much appreciated!
 
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