John W. Fitzpatrick said there have been several independent sightings of a bird that appears to be an ivory-billed woodpecker.
A video clip of one bird, though blurry, shows key features, including the size and markings, Fitzpatrick reported.
"The bird captured on video is clearly an ivory-billed woodpecker. Amazingly, America may have another chance to protect the future of this spectacular bird and the awesome forests in which it lives," Fitzpatrick, director of the Cornell Laboratory of Ornithology, said in a statement.
Once prized by Indians who believed that its bill possessed magical powers, the ivory bill was also hunted in the late 19th and 20th centuries for its feathers, popular on ladies hats. Loss of habitat was its main threat, however.
The ivory-billed woodpecker, one of the largest such birds in the world, is one of six North American bird species thought to have become extinct since 1880. While somewhat rare, the bird ranged widely across the southeastern United States until logging eliminated many forests between 1880 and the 1940s.