Long Slog for the Ivory-Billed Woodpecker
Efforts to create a suitable habitat for a striking bird that may or may not be extinct continue a half decade after its reported but uncorroborated resurrection.
Against all odds, the critically endangered ivory-billed woodpecker may still be hanging on in a desolate handful of bottomland swamps in the American Southeast.
Depending on who's asked, the last putative sighting of the large black-and-white bird occurred in early 2007 in the Florida Panhandle or the spring of 2008 in a Louisiana bayou. And there hasn't been an undisputed report of ivory-bills for nearly 70 years, more than twice the bird's maximum lifespan.
The putative rediscovery of the bird in 2005, announced with much fanfare at a Washington, D.C., press conference that included two U.S. Cabinet secretaries, garnered the most attention outside of the birding world.
Prompted by a paper appearing in the journal Science announcing the bird's rediscovery in an Arkansas bottomland forest, the conference saw lead author and Cornell University ornithologist John Fitzpatrick proclaim, "Amazingly, America may have another chance to protect the future of this spectacular bird and the awesome forests in which it lives." The federal government subsequently announced plans to fund $10 million in Arkansas habitat restoration for the long-suffering woodpecker.
Thus, in making pronouncements about its possible extinction, it's easy to understand why the mainstream ornithological community remains as wary as the bird, even as they have harnessed robotic cameras, computer modeling and help from NASA to the traditional birding tools of binoculars and patience. But a few respected researchers are convinced that it may remain in numbers viable enough to survive.
"If no further observations are made, it could be another 30 years before the species is declared extinct," said Chuck Hunter, a biologist with the U.S. Fish and Wildlife Service in Atlanta. "But within the U.S. Fish and Wildlife community, we are not ready to declare it extinct. I have not seen compelling evidence to suggest it's extinct."
Even so, its survival as a species is critically dependent on the bird's swamp forest, bottomland hardwood habitat that is today found in the Big Woods of Arkansas, the bayous of eastern Louisiana and the cypress-dominated swamp forests of northwest Florida.
In the six years since the 2005 announcement that the bird had resurfaced, there has been a continual effort, particularly in Arkansas' lower Mississippi Valley, to restore the woodpecker's native habitat. The efforts include practicing better forest management, reclamation of previous bottomland forests from agriculture as well as pre-emptive purchases of habitat under threat of encroachment.
Ivory-billed woodpeckers need a forest big enough so that a few old trees — trees injured by lighting, wind, disease or old age — are always dying and therefore filled with tasty insects.
With its unusually strong beak, the bird can strip bark from dead or dying trees like no other woodpecker, thus exposing its preferred prey — larvae of the wood-boring longhorned beetle. These beetles only attack dead or dying trees.
"When ivory-billed woodpeckers are breeding and having chicks, there's great demand for protein," said Doug Zollner, a conservation biologist at The Nature Conservancy in Arkansas. "When trying to feed their young, these bugs are their protein."
A mated pair needs an estimated six square miles of uncut forest to feed a small family.
And while there are efforts afoot to restore some habitat for the bird, the hope is that its friends won't turn out to be its enemies this time.
"Although the demise of the ivory-billed woodpecker is attributed to habitat loss, there are compelling arguments now that that is not why the bird disappeared," said Geoffrey Hill, an ornithologist at Auburn University. "The museum guys wanted them for their collections, so they were pretty much shot out between 1905 to 1910."
Why would people go out and shoot birds that they knew were endangered?
"For a biologist at the turn of the 20th century," said Hill, "the focus was on documenting life's diversity; extinction wasn't viewed in the same way it is now."
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Its historical range covered much of the Southeast, including the whole of Florida, Louisiana, most of east Texas and Mississippi. Today, less than 20 percent of the Mississippi Valley's historical forest remains. The toll on the woodpeckers was even greater: By the end of World War II, collectors and lumbermen had obliterated the species, reducing the historical population of perhaps as many as tens of thousands by an estimated 99.9 percent.
In 1939, Jim Tanner, a Cornell ornithologist who spent much of his professional career documenting the last remaining populations of the bird, estimated that about 25 ivory-billed woodpeckers remained in four or five large areas in Florida, Louisiana and South Carolina. The last well-documented population dates from the 1930s and occupied a stand of old-growth bottomland hardwood forest in the privately owned 81,000-acre Singer tract in northeastern Louisiana.
The area was by no means pristine. The Chicago Mill and Lumber Company — which specialized in making wooden boxes and caskets – logged that habitat of sweetgum and oak, tapping it hard to rebuild Chicago after the great fire of 1871. But World War II, with its insatiable need for supplies delivered in wooden boxes, put the final nail in the Singer tract's coffin.
By 1944, the tract's ivory-billed population had been reduced to a lonely female seen flying over remnants of its once untamed forests. Subsequent reported sightings of the bird became few and far between.
"It doesn't take a rocket scientist to identify this ivory-billed woodpecker," said Michael Collins, a self-taught ornithologist and an MIT-educated mathematician at the Naval Research Lab's Stennis Space Center facility in Mississippi. "It's a very striking bird, but it does takes determination to find it."
In truth, the ivory-bill is often confused with the more common pileated woodpecker, but experienced observers like Collins can easily distinguish between the two. Typically 1.5 feet tall with a 2.5-foot wingspan, the ivory-bill can weigh more than a pound. A characteristic white stripe extends down the sides of its neck and back.
"It's a pretty fantastic thing, that a bird could exist in the U.S. and be so hard to document," Hill said. "But the bird has got this combination of extreme wariness and tough [swamp forest habitat]." Plus, the bird's keen sense of hearing and eyesight enable it to detect people before they detect it.
Still, his group of Auburn University researchers spent five months along the Florida panhandle's Choctawhatchee River in 2006 and claimed seven ivory-billed sightings.
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Renewed hope for the bird came in 2004 with expert analysis of a four-second video of a sighting a couple of miles north of I-40 in east-central Arkansas' Cache River National Wildlife Refuge. Late in the afternoon, amateur ornithologist David Luneau had just turned off his boat's trolling motor in order to get up into the woods to check his eighth and final remote camera.
"That's when the bird flew off," said Luneau, a computer and electronics engineer at the University of Arkansas at Little Rock. "I saw it going directly away from me. There was just so much white, which you don't see when a pileated flies away from you.
The subsequent 2005 refereed paper on the sighting (Luneau was a co-author) made the cover of the journal Science. "I think it's conclusive," said Luneau, "but my sighting is in dispute."
Martjan Lammertink, a Cornell University ornithologist, says the hope was that there was an indication of a small Arkansas population. But since then, he says, it's clear there's no population there. (He's also pessimistic about finding the bird in ranges outside of the U.S.)
Thus, when Hurricane Katrina slammed into Louisiana who would have ever dreamed that a Category 5 storm would also have a potential silver lining?
But Collins used the serendipity of Hurricane Katrina to search the back bayous of eastern Louisiana. He began looking for ivory-billed woodpeckers in November 2005, shortly after Hurricane Katrina passed through Louisiana's Pearl River.
"When I arrived in the Pearl River area in the fall of 2005, there were huge numbers of dead and dying trees," says Collins. They made it much harder to access remote areas. Blackberry thickets have taken over the openings created by the fallen trees, which he says makes such areas even more attractive to a reclusive species.
His first sighting was nearly three months later on a sunny, mild winter's morning on Louisiana's English bayou. Drifting down the channel in his kayak, the bird flushed from the right bank and flew into the woods.
Since that February, Collins has claimed nine sightings in the Pearl River area. He wrote a March 2011 article in the Journal of the Acoustical Society of America detailing his 2008 video recording of the woodpecker's putative double-knock.
The woodpecker uses its double-knock drumming sound on a resonant dead or hollow branch as a means of demarcating its territory, or for keeping in contact with its mate. Such double-knocks are so loud that they can be confused with the pounding of an ax.
Collins recorded a single double-knock event. While Lammertink argues such knocks are only convincing if a woodpecker does it 10 or 15 times, Fish and Wildlife's Hunter says Collins may have captured the real thing.
If so, what can be done to protect the bird's potential remaining habitat in northwest Florida, eastern Louisiana and the Big Woods of Arkansas?
"It's a combination of using more appropriate wildlife-oriented forestry practices," said Hunter. "It's also taking areas that had been converted to agricultural land or pine plantation and trying to convert it back to bottomland hardwoods."
Even so, Lammertink says it will take 20 to 30 years to have the kind of forest that the ivory-billed woodpecker would again find to be a good breeding and foraging habitat.
"In the Florida Panhandle, there's vast habitat for the bird," said Hill. "In the Choctawhatchee, they took out mostly cypress, but otherwise the forest was left intact."
The Nature Conservancy's Zollner says that while the Singer tract is being restored, that process is only halfway complete. Although significant acreage has been bought up by forest restoration groups, much of the area still remains in soybeans.
But some 26,000 acres of forest in the Big Woods/Cache river wilderness region has already been restored or is in the process of being restored.
"We have very young forests [in the Cache River area]," said Zollner. "But we're missing the historically mixed-age component of the forest, of older trees that are dying at the same time the young ones are growing up. That's the component that would provide the food source for ivory-billed woodpeckers."
One means of providing remaining woodpeckers with a fresh source of foraging habitat is via "mortification," a technique in which healthy trees are intentionally killed by having foresters chainsaw a 4-inch-wide strip (or girdle) all the way around the tree.
Death is caused by the interruption of the flow of water and nutrients to the crown of the tree. Once a double-girdled tree starts dying, it will attract beetles and other boring insects within a few months.
"Since 2005, in the Cache river area, we've girdled several thousand trees," said Zollner, who notes that morticulture treatments are continuing on a small scale along Arkansas' Bayou DeView.
If an ivory-billed population were located, Lammertink says the primary goals would be to protect older forest habitat in the region while increasing the amount of deadwood. He also recommends putting in some sort of structure at the tree bottoms to prevent the woodpeckers' nests from being preyed upon by rat snakes.
"We're not very optimistic about the bird at this point," said Lammertink. "We've stopped systematic searches, but we still think small numbers, a dozen or less, may still be in some surprising corner."
But Collins argues that if there had only been that small a number since 1950, there is no way they could have survived until present. With potential imbalances between males and females, inbreeding, infertility, sickness and old age, as well as the inability to find mates, he says the bird would have become extinct very quickly.
Collins says the maximum number that could still exist is more realistically about a hundred. "There couldn't be a thousand because someone would have found an active nest," said Collins, "but a hundred birds could have hidden out."