Ivory-billed woodpecker

The ivory-billed woodpecker (Campephilus principalis )is one of the rarest birds in the world and is considered by most authorities to be extinct in the United States. The last confirmed sighting of ivory-bills was in Cuba in 1987 or 1988. Though never common, the ivory-billed woodpecker was rarely seen in the United States after the first years of the twentieth century. Some were seen in Louisiana in 1942, and since then, occasional sightings have been unverified. Interest in the bird rekindled in 1999, when a student at Louisiana State University claimed to have seen a pair of ivory-billed woodpeckers in a wilderness preserve. Teams of scientists searched the area for two years. No ivory-billed woodpecker was sighted, though some evidence made it plausible the bird was in the vicinity. By mid-2002, the ivory-billed woodpecker's return from the brink of extinction remained a tantalizing possibility, but not an established fact.

The ivory-billed woodpecker was a huge bird, averaging 19–20 in (48–50 cm) long, with a wingspan of over 30 in (76 cm). The ivory-colored bills of these birds were prized as decorations by native Americans. The naturalist John James Audubon found ivory-billed woodpecker in swampy forest edges in Texas in the 1830s. But by the end of the nineteenth century, the majority of the bird's prime habitat had been destroyed by logging . Ivory-billed woodpeckers required large tracts of land in the bottomland cypress, oak, and black gum forests of the Southeast, where they fed off insect larva in mature trees. This species was the largest woodpecker in North America, and they preferred the largest of these trees, the same ones targeted by timber companies as the most profitable to harvest. The territory for breeding pairs of ivory-billed woodpeckers consists of about three square miles of undisturbed, swampy forest, and there was little prime habitat left for them after 1900, for most of these areas had been heavily logged. By the 1930s, one of the only virgin cypress swamps left was the Singer Tract in Louisiana, an 80,000-acre (32,375-ha) swathe of land owned by the Singer Sewing Machine Company. In 1935 a team of ornithologists descended on it to locate, study, and record some of the last ivory-billed woodpeckers in existence. They found the birds and were able to film and photograph them, as well as make the only sound recordings of them in existence. The Audubon Society, the state of Louisiana, and the U.S. Fish and Wildlife Service tried to buy the land from Singer to make it a refuge for the rare birds. But Singer had already sold timber rights to the land. During World War II, when demand for lumber was particularly high, the Singer Tract was leveled. One of the giant cypress trees that was felled contained the nest and eggs of an ivory-billed woodpecker. Land that had been virgin forest then became soybean fields.

Few sightings of these woodpeckers were made in the 1940s, and none exist for the 1950s. But in the early 1960s ivory-billed woodpeckers were reported seen in South Carolina, Texas, and Louisiana. Intense searches, however, left scientists with little hope by the end of that decade, as only six birds were reported to exist. Subsequent decades yielded a few individual sightings in the United States, but none were confirmed.

In 1985 and 1986, there was a search for the Cuban subspecies of the ivory-billed woodpecker. The first expedition yielded no birds, but trees were found that had apparently been worked by the birds. The second expedition found at least one pair of ivory-billed woodpeckers. Most of the land formerly occupied by the Cuban subspecies was cut over for sugar cane plantations by the 1920s, and surveys in 1956 indicated that this population had declined to about a dozen birds. The last reported sightings of the species occurred in the Sierra de Moa area of Cuba. They are still considered to exist there, but the health of any remaining individuals must be in question, given the inbreeding that must occur with such a low population level and the fact that so little suitable habitat remains.

In 1999, a student at Louisiana State University (LSU) claimed to have seen a pair of ivory-billed woodpeckers while he was hunting for turkey in the Pearl River Wildlife Management Area near the Louisiana-Mississippi border. The student, David Kulivan, was a credible witness, and he soon convinced ornithologists at LSU to search for the birds. News of the sighting attracted thousands of amateur and professional birders over the next two years. Scientists from LSU, Cornell University, and the Louisiana Department of Wildlife and Fisheries organized an expedition that included posting of high-tech listening devices. Over more than two years, no one else saw the birds, though scientists found trunks stripped of bark, characteristic of the way the ivory-billed woodpecker feeds, and two groups heard the distinct double rapping sound the ivory-billed woodpecker makes when it knocks a trunk. No one heard the call of the ivory-billed woodpecker, though this sound would have been considered definitive evidence of the ivory-billed woodpecker's existence. Hope for confirmation of Kulivan's sighting rested on deciphering the tapes made by a dozen recording devices. This was being done at Cornell University, and was expected to take years.

By mid-2002, the search for the ivory-billed woodpecker in Louisiana had wound down, disappointingly inconclusive. While some scientists remained skeptical about the sighting, others believed that the forest in the area may have regrown enough to support an ivory-billed woodpecker population.

See also Deforestation; Endangered species; Extinction; International Council for Bird Preservation; Wildlife management

[Eugene C Beckham ]

RESOURCES

BOOKS

Collar, N. J., et al. Threatened Birds of the Americas: The ICBP/IUCN Red Data Book. Washington, DC: Smithsonian Institution Press, 1992.

Ehrlich, P. R., D. S. Dobkin, and D. Wheye. The Birder's Handbook. New York: Simon & Schuster, 1988.

Ehrlich, P. R., D. S. Dobkin, and D. Wheye. Birds in Jeopardy: The Imperiled and Extinct Birds of the United States and Canada, Including Hawaii and Puerto Rico. Stanford: Stanford University Press, 1992.

PERIODICALS

Gorman, James. "Listening for the Call of a Vanished Bird" New York Times, March 5, 2002, F1.

Graham, Frank Jr. "Is the Ivorybill Back?" Audubon (May/June 2000): 14.

Pianin, Eric. "Scientists Give Up Search for Woodpecker; Some Signs Noted of Ivory-Billed Bird Not Seen Since '40s" Washington Post, February 21, 2002, A2.

Tomkins, Shannon. "Dead or Alive?" Houston Chronicle, April 14, 2002, 8.