CHOCTAWHATCHEE RIVER, Fla., Oct 10 - The skeptics say it can't be done.

Obtaining conclusive evidence that the legendary ivory-billed woodpecker survives in an American swamp may be as hard as proving that string theory explains everything in the universe.

But that will not stop true believers who revel as much in the search as in the discovery.

Photo by Glynn Wilson

Could there be a pair of shy, elusive ivory-billed woodpeckers hiding and watching from the tree tops?

Upon hearing recently that a research team led by Auburn University Professor Geoff Hill published audio evidence that a population of ivory-billed woodpeckers survives in a remote river basin in the panhandle of Florida, I just had to see this river and attempt to meet these woodpeckers myself.

I loaded up the Chevy van, put the canoe on top, and made the long drive east down Highway 90, past Crestview, Florida, until the Choctawhatchee River (pronounced Choct-a-hatchee) bridge came into view.

It is named "the river of the Choctaws" because it was once home to that native band of Indians, ran out of the territory by the U.S. Army under Gen. Andrew Jackson just as my ancestors the Cherokee were ran out of north Alabama.

Floating along as quietly as possible, hoping for a lucky encounter, it's not hard to imagine hearing the high-pitched, trumpet-like call of the ivory-billed woodpecker while straining for a glimpse of this magnificent bird amongst the tree tops.

There are woodpeckers of every variety along the way, calling their mates, issuing warnings, tapping on trees to find the grub worm and "betsy-bug" larvae they love to eat.

Professor Hill, an ornithologist at Auburn's College of Science and Mathematics, reported his findings in Avian Conservation and Ecology, an electronic scientific journal. He claims to have seen an ivory-bill in flight on 14 occasions and heard its signature double knock, while kayaking on the river in May 2005. He was leading two research assistants on a search in the remote part of the panhandle so unexplored that few bird records of any kind exist for the area.

"These swamps are very rarely visited," he said. "I think this area has barely ever been visited by somebody with book knowledge of birds."

The team captured 300 recordings consistent with the sounds of the ivory-billed woodpecker. Cornell University researchers stunned bird-lovers last year by announcing that the ivory-bill had been rediscovered in the Big Woods of Arkansas, although the evidence in that discovery is still subject to debate and controversy. A concerted search based on another alleged sighting was conducted in the upland cypress swamps of the Pearl River basin in Louisiana in 2002.

With a wingspan of three feet and a height of 21-inches tall, the ivory-bill is the world's second largest woodpecker next to the imperial woodpecker of Mexico. The last survivors who confirmed a sighting of the ivory-bill were so impressed with it they dubbed it the "Lord God bird," because the first thing they said when encountering it was, "Lawd Gawd."

The ivory-bill is black with large white stripes. It has a long, ivory-colored bill and a tall crest on its head. The male's crest is red and the female's is black. Researchers say it requires large tracts of unbroken hardwood swamp, territory that is vanishing in the American South as the population grows and the suburbs sprawl.

Photo by Glynn Wilson

This tree on by the river north of Highway 90 shows signs of some very large woodpeckers nesting in the trunk...

Spotting an ivory-bill would be to birders what finding the holy grail would be to pilgrims searching for the cup of Christ.

The ivory-bill is listed as an endangered species but thought to be extinct since the early 1970s. But on April 1, 1999, Louisiana State University forestry student David Kulivan says he spotted a pair on a water oak while sitting under a tree, camouflaged, stalking turkey.

He insisted it was not an April Fools Day joke, and a panel of experts gave his story enough credence to mount an organized search. Dr. James Van Remsen conceded then that the odds were heavily against the expedition coming away with pictures or video of the ivory-bill, or even sound recordings of its unique nasal call. It would be like finding a dodo bird long after it was declared extinct.

No evidence of ivory-bills turned up in that search, but the researchers in Arkansas last year came up with a few seconds of low quality, shaky video, which many scientists say is inconclusive.

The date of the last ivory-bill sighting is the subject of dispute among scientists and birders. Many media reports date the last ivory-billed sightings to the 1930s, to a tract of land owned by the Singer Sewing Machine company near Tallulah, La., across the Mississippi River from Vicksburg, Miss.

In his Birds of Louisiana, the late Dr. George H. Lowery Jr., one of the world's most renowned bird experts, tells of watching four ivory-bills feed there on a dead snag on a rainy Christmas morning in 1933.

But Dr. Remsen is in possession of three photographs of an ivory-bill couple taken in 1971, which could represent the last confirmed sighting before the grand and rare woodpecker disappeared into extinction.

"Those photographs are disputed by some as fakes," Dr. Remsen said. "I happen to be 100 percent confident that those are good photographs, but that doesn't do any good for the people who think those are mounted ivory-billed woodpeckers in a tree. If that's not a real bird, I'll turn in my ornithology credentials. And I talked to the guy who took the pictures, so I'm convinced."

The photographer's name and the exact location of the sighting in northeast Louisiana are closely held secrets. Another search is underway in Cuba, where there are unconfirmed sightings as well.

Loggers clear-cut much of the area where the ivory-bills lived before World War II during the massive timber harvest of the early 20th century. Working with giant cross-saws, then shipping the trees out by rail to feed the needs of a growing, industrial population, they felled Southeastern forests from North Carolina to Texas, taking the rest in the 1950s and '60s.

A mating pair of ivory-bills would need at least a six-square-mile area of virgin bottomland forest habitat to survive, experts say. Why should people care if the ivory-bill or other species survive or die? Isn't extinction part of nature?

Yes, says the theory of evolution and natural selection, adaptable species survive while the weak perish. The recent problem of biodiversity loss has to do with the intervention of Homo sapiens, say experts such as Edward O. Wilson of Harvard. In his 1992 Pulitzer Prize-winning book The Diversity of Life, he estimates only 4.3 percent of the earth's land surface is legally protected, a critical factor in dooming about 27,000 species each year.

Even the dodo's extinction can be blamed on Portuguese and Dutch explorers who fed on the flightless bird in the 1500s and 1600s while exploring islands in the Indian Ocean.

All of this information runs through my head as I listen and look for the ivory-bill for the better part of an afternoon.

The flicker, also known as the yellow-hammer, goes "Wick wick, kee-you, flicka, flicka."

The red-bellied woodpecker sings "Chirr-r-r-r, chaw, chaw."

Further into the dark woods came the "kuk-kuk, kuk-kuk" of the pileated woodpecker, a close cousin of the irovy-bill.

If there is a place where there are a sufficient number of ancient trees to support ivory-bills, the Choctawhatchee River basin may be it. This is a metropolis of serious woodpecker habitat, so just being here is enough to give one hope of a sighting, enough to stir the imagination at the strangest, most distant call.

Searching for another few hours turned up no sign of the shy and elusive ivory-billed woodpecker, but the trip and the float was worth it anyway. Chances are I'll come back at it again this winter, when the foliage dies down and the snakes are fast asleep in their holes.

If there is a pair of mating ivory-billed woodpeckers out there somewhere, what a unique thrill it would be to see them - and be the first to get a definitive picture.

Photo by Glynn Wilson

A view up the Choctawhatchee River from Oct. 10, 2006.