The air smells like a bowl of pet turtles, funky and ripe. It is a lovely spot, if you're a venomous serpent. They own the place. The water moccasins are as fat and sassy as house cats, as thick around as a toddler's thigh, lounging around like throw pillows. Locals call this primordial ooze the Big Woods, but the flooded forest feels more like Big Swamp, covered with greasy brown water that flows through the tupelo and cypress trees. The beavers, bullfrogs and mosquitoes are loving it.

For 216 days, Tim Barksdale, a world-class nature photographer and pursuer of birds, sat quietly here in his canoe, watching, waiting. Sometimes, he'd get out and stand in the muddy waist-deep water, dressed head to toe in camouflage, peering into the forest with his binoculars or high-definition video camera. In 2,600 hours in the swamp, he never saw the ivory-billed woodpecker, though he is pretty sure he heard the bird -- its staccato double-knock (POP-pop) -- once.

Barksdale is a rugged, bearded mountain man type from the wilds of Montana, no stranger to discomfort, happy to spend his nights sleeping in his truck, his days up to his armpits in mire. But hearing those milliseconds of woodpecker drumming, just that one taste, he says, "was electric." A hit of pure delight. It brought him, literally, to tears, and afterward? He says, "I felt weak."

It is for Barksdale, and his tribe of woodpecker hunters, a kind of beautiful obsession.

The announcement in late April of the rediscovery of the ivory-billed woodpecker in the Big Woods of eastern Arkansas -- the first confirmed sighting in the United States since 1944 -- made headlines around the globe. "It is the most exciting news of my lifetime," said Steve Runnels, president of the American Birding Association.

But even for those who wouldn't know a house sparrow from a painted bunting, there was something amazing about it.

Lost species of obscure slugs and drab lichen get rediscovered all the time. But this was different. The ivory-billed woodpecker was living, very, very on the q.t., in our own back yard.

What's weird: It is a hulking, big bird, larger than a raven, dressed in a flashy black-and-white tuxedo and sporting a pointed red hat like Jacques Cousteau, a bird that defends its territory by screaming kent-kent-kent! a call compared to blasts from a child's toy trumpet.

And this bird has been hiding out in a national wildlife refuge, unseen for 60 years? It's crazy.

Perhaps that's why the code name chosen by the search team for the woodpecker was Elvis.

"This species just has this nasty habit of disappearing," says Phillip Hoose, author of "The Race to Save the Lord God Bird." Lord God Bird is one of the dozen common names for the ivory-billed woodpecker because those who saw one in the late 19th century were often supposed to exclaim, "Lord God, what a bird!"

"It's just been so spooky, how hard the bird is to find," says Barksdale, floating in his canoe through the murk of Bayou de View, not too far from the spot where the ivory-billed was sighted, the last time in February. "Somewhere Elvis is out there doing his thing, sitting on a dead branch, preening and calling, and we cannot find him."

It seems the natural world still holds mysteries for those who tune in, and a delicious one is this: Why is the ivory-billed woodpecker so wonderfully, so maddeningly elusive?

Elvis Lives!

On a bright sunny Saturday at the end of May in the little town of Clarendon, about halfway between Little Rock and Memphis, the locals hosted their annual Big Woods Birding Festival. But this year, with the rediscovery, it was all about the woodpecker. They were selling ivory-billed posters, books and T-shirts that read "Got Pecker?" Penny Childs would cut your hair to look like a woodpecker for 25 bucks. There was an Elvis impersonator crooning "don't be cruel." Federal and state wildlife agents set up tables piled with information about woodpeckers and how to identify the ivory-billed from its cousin, the relatively common pileated woodpecker, as phone calls were coming in from around Arkansas from people who thought they spied an ivory-billed at their bird feeders (which they almost assuredly did not).

There are high hopes among the Chamber of Commerce types that the woodpecker rediscovery would draw throngs of bird nuts carrying telescopes on tripods and fistfuls of cash to the poor Arkansas Delta. The U.S. Fish and Wildlife Service was concerned enough about a birder invasion that the refuge manager posted a couple armed officers at the Highway 17 bridge, the closest put-in for a canoe and smack dab in the middle of the two-mile stretch where the sightings have occurred, to keep the hordes out of the restricted area. Alas, it was not to be: The birders have (mostly) stayed away.

There are a couple of reasons why: The ivory-billed remains the rarest of the rare. Incredibly difficult to glimpse in the best of seasons -- the winter months, when the trees are bare of leaves -- and in the spring and summer, when the swamps explode with green, it is nearly impossible to find. That, and the consensus among responsible birders is that the wary woodpecker might need quiet time after its return to the world stage. The researchers still are not certain whether there is just one male bird out there -- the last of his species -- or, at best, a few adult pairs and their young.

'Too Beautiful'

The Birding Festival was a good excuse for the ivory-billed woodpecker search team to reunite and tell their stories -- a crack SWAT-style team composed of some of the best birders in the world, under the auspices of the Cornell University Ornithology Laboratory and the Nature Conservancy. The Conservancy, a nonprofit environmental organization, has been working for years to preserve Big Woods habitat, along with state and federal wildlife agencies, long before anyone even suspected that an ivory-billed might be lurking out there in 500,000 acres of forest.

Over at the American Legion Hall, the room was packed to the rafters. On a table at the front, enclosed in a glass case, was a stuffed ivory-billed woodpecker, perched on a branch by its taxidermist. It is the closest to the living bird most people will ever come. The bird's long bill is a wickedly powerful weapon that it employs, as one naturalist put it, "to hammer like an angry man with an ax" at the dead and dying trees while searching for the beetle grubs that live beneath the bark. The dead bird's eye is big and egg white, and there's a Z-shaped swoosh of white that runs from its cheek to back, like a flamboyant mark of Zorro. But there is no vibrancy in the museum specimen, a kind of sad mummy.

Hoose, author and Nature Conservancy staffer, explains to the audience that the ivory-billed woodpecker has been elusive from the beginning of scientific enquiry. The tale he tells makes you feel by turns hopeful and depressed. Early in the 1800s, John James Audubon, who painted two portraits of the bird, was already worried about its survival. Indians coveted its feathers and beak for ceremonial dress, and early settlers used its body for gunshot pouches. "It was too big, too bold, too beautiful," Hoose says, for its own good.

But the real end times for the woodpecker began in the post-Reconstruction era, from the 1880s to the 1940s, when a nation hungry for timber logged the old woods and everything else along the rivers of the American Southeast. Once the Mississippi Delta bottomlands ran from Memphis to the Gulf of Mexico, 60 miles across and many hundreds of miles long. Gone, gone. Only the seeds and stems remain. But that is an old story.

Less known is the role that science and fashion played -- as collectors for amateur naturalists and the nation's foremost museums sought the last of the last woodpeckers, shooting them for their skins, and hunters gathered the feathers for the hat trade for the haute couture of ladies from Boston to Savannah (the so-called Plume Wars, which gave rise to today's Audubon Society, which was formed to fight the slaughter).

By 1920, the ivory-billed woodpecker was thought to be toast -- a goner after the extermination of the passenger pigeon (1914) and the Carolina parakeet (1918). But in 1924, Cornell ornithologist Arthur Allen found a pair in Florida. After he and his wife left camp, somebody shot the creatures.

Later, the final redoubt was thought to be a tract of remnant wood in northeast Louisiana owned by the Singer sewing machine company, where the "last" population was studied, first by Allen in 1935, and then by his protege, the young and dogged James Tanner, who did the intensive fieldwork that today forms almost the entire corpus of knowledge about the bird and its lifestyle. (Turn-ons: beetle larvae and fast flight. Turn-offs: lumber companies and swamp drainers.) The Singer Tract was so wild and woolly and the woodpecker there so precious that earlier conservationists appealed to Congress to turn the place into a national park. It was not to be. The Chicago Mill and Lumber Co. mowed it down to make ammunition crates and caskets in World War II.

In April 1944, Don Eckelberry, who illustrated the early Audubon field guides, trekked to the Singer Tract and saw what the scientific community long assumed was the last bird, a lone female, calling for a mate that was no longer there. Eckelberry nailed the essence of the bird in his description: "She came trumpeting into the roost, her big wings cleaving the air in strong direct flight, and she alighted with one magnificent upward swoop. Looking about wildly with her hysterical pale eyes, tossing her head from side to side, her black crest erect to the point of leaning forward, she hitched up the tree at a gallop."

One of the kids who had accompanied Eckelberry to the site later returned. The roost tree, he recalled, had blown down in a wind storm. And the curtain went down on the ivory-billed. Or so we thought.

Knock, Knock

Of course, there were rumors, glimpses, mirages. They thought the bird might have reappeared in the Big Thicket woods in east Texas, but reports were never substantiated. On April Fool's Day in 1999, a 20-year-old forestry student said he saw the bird while out hunting in the Pearl River Wildlife Management Area north of New Orleans, which sparked a widely publicized search there in 2002, sponsored by the binocular manufacturer Zeiss, and . . . nada.

Encouraging double-knocks picked up by researchers' sophisticated microphones on the Pearl were later shown to be not woodpecker drums but rifle blasts. "It was like chasing a ghost," says David Luneau, an expert birder and obsessed ivory-billed chaser, as well as a professor at the University of Arkansas, who participated in the Zeiss hunt and later, the successful one in the Big Woods.

And so it went -- chasing ghosts -- until the afternoon of Feb. 11, 2004, when a shiitake mushroom farmer from Hot Springs named Gene Sparling was slipping through the Bayou de View woods in his kayak. By his own admission, Sparling is a novice at bird identification. "It was just a wonderful sublime moment of contentment, just in awe, feeling like I was the luckiest person in the world, for just being there," Sparling recalls. "And just then this large woodpecker came into view. My god, that's the largest pileated woodpecker I've ever seen. Flared its wings, landed on the base of a tree. Sixty feet away. Long neck, red crest with a particularly fine point. Thing I noticed most was that the back was white, parchment white, and he seemed particularly animated. He gave several quick jerks, and flew away, his profile was long and straight, rather than undulating. I thought, could that be the ivory-billed woodpecker? But no, they were extinct. And have been all my life."

But Sparling posted an obscure note on a canoe Web site, which wound its way to the odd couple of Tim Gallagher, editor of Living Bird magazine at the Cornell Lab of Ornithology, and Bobby Harrison, a photography professor at Oakwood College in Alabama. Gallagher, lean and Yankee, and Harrison, Falstaffian and as Southern as grits, had been traveling around the swamps for years, tracking down rumors of ivory-billeds. After speaking with Sparling, they were back with him in the Big Woods on Bayou de View within the month. On their second day out, eureka. "We both cried out simultaneously, IVORY BILL!" Gallagher writes in his book "The Grail Bird."

Under the auspices of the Cornell bird lab and the Nature Conservancy, a search was launched in April 2004 to document the finding. Absolute secrecy was required, they felt, or the place would be inundated with thousands of birders, or worse, they would be laughed out of academe as just another false report. Members of the team (which would number about 50 part-timers and 30 full-time) were required to sign confidentiality agreements. Once on site at Brinkley, they even moved out of their motels, fearful that the locals would suspect something was up (after all, it was duck season, and nobody in the Elvis search team was carrying shotguns; the Nature Conservancy bought them an old house).

Some of the best birders in the world went after the ivory-billed equipped like a NASA mission to the moon, slogging through the swamps of the Cache and White River national wildlife refuges and state lands, loaded with cameras, telescopes, recordings of the bird calling (made in 1935 and used to entice a response). They placed super-sensitive listening devices in the trees and recorded thousands of hours of swampy blurps and cackles and groans. They hunted for nests and roosts and signs of stripped bark. They were up in airplanes and used satellite data, searching for what they thought (from the Tanner papers of the 1940s) would be prime habitat.

Showing a reporter around the swamp, Martjan Lammertink of the University of Amsterdam and Cornell, a recognized authority on large woodpeckers (the extinct Imperial in Mexico and the living Great Slaty in Indonesia), came back to the same puzzle: How can Elvis be so elusive?

Lammertink never saw one. Lord God, he tried.

Neither did the head of the expedition, John Fitzpatrick of Cornell. Neither did any of the members of Cornell's crack birding team known as the Sapsuckers. In all, the searchers, drawn from across the country, were out there 240 days, which equals more than 3,000 "person days" of observation.

What did they get? Seven sightings.

There were no recordings of the kent call. Maybe a couple of double-knock drummings (other woodpeckers also peck bark, and the woods here contain not only ivory-bills, but hairy, red-bellied, pileated, red-headed, downy and sapsucker woodpeckers).

Lammertink estimates that in 2005 the chances of a trained observer seeing an ivory-billed woodpecker on any given day is 1 in 1,013.

So, good luck.

They did get four seconds of blurry video, which was shot almost by accident by Luneau and had to be analyzed for months, in slow-motion and freeze-frame, like the Zapruder film of the Kennedy assassination, but which is the best documentation so far and was used to support their paper in April in the journal Science. (In an ideal world, there would be a crisp photo or clear video, but nobody's been able to get either yet.)

"I don't know why we can't find the bird more consistently," Lammertink says. His best guess: the ivory-billed woodpecker is flying long commutes, looking for its dead trees stuffed with beetles, and they're seeing him, and maybe her, as they make their way back and forth, through a narrow stretch of swamp. There's 500,000 acres out there. The team has searched only a fraction of it. But even so, Lammertink says the whole Big Woods might be able to support only a dozen adult pairs and their young, which would explain how they remain the rarest of the rare.

But there is some good news. The wildlife refuges of the Big Woods are growing; each year there are more acres set aside and the trees grow older, bigger, more beetley. The habitat improves, ever so slowly. So the ivory-billed woodpecker, with its hysterical eyes, maybe has a shot. Or not. It has fooled us before.

Birders enter Papaw Lake in Arkansas, where the woodpecker was sighted for the first time in six decades but remains elusive. "It's just been so spooky, how hard the bird is to find," says one birder.Scott Simon, right, director of the Nature Conservancy in Arkansas, hopes for a rare sighting of the ivory-billed woodpecker on the Cache River. Gene Sparling, left, had one in the Bayou de View woods on Feb. 11, 2004. "It was just a wonderful sublime moment of contentment, just in awe," he says.A 1937 photo of two ivory-billed woodpeckers in the trees on Singer Tract, La.Penny's Family Hair Care appeals to the birding aficionados in Brinkley, Ark.