In Latest Challenge, Researchers Stand by Ivory-bill Evidence

March 17, 2006

By Pat Leonard

In addition to sightings and possible audio recordings of Ivory-billed Woodpeckers in the Big Woods of Arkansas, the now-famous “Luneau video” has been a key element supporting the assertion that at least one Ivory-billed Woodpecker was present in  April 2004. A peer-reviewed article challenging that conclusion has been published in the March 16 issue of Science. A response by Cornell Lab of Ornithology director Dr. John Fitzpatrick and colleagues is included in the same issue.

The challenge is led by David Sibley, renowned author of The Sibley Guide to Birds. In the article, Sibley and three coauthors claim the features of the bird in the Luneau video do not eliminate the possibility of its being a normal Pileated Woodpecker.  For example, they argue that the white seen on the bird in the video as it flies away from the viewer is the large white patch on the underwing of a pileated. They suggest that the wings twist in such a way that the bottom surface of both wings are visible and the top surface largely hidden. Fitzpatrick et al. interpret this same footage as showing extensive white on the top side of the bird, conspicuous black wingtips, and the absence of black along the rear edge of the wing—characteristic of an ivory-bill. They state that the "wing-twisting" hypothesis contradicts all models and photographic analyses of flapping flight in birds.

Sibley et al. also claim that the perched bird, seen just before launching into flight, is a Pileated Woodpecker with its wing opened and extended vertically, thus also showing its large white underwing patch. However, Fitzpatrick et al. interpret this same portion of the video as a side view of an ivory-bill's wing as it begins to open. The underwing of a Pileated Woodpecker, they say, would show a broad black border of feathers, which isn't seen in the image from the video. They also point out that the flying bird in the video shows a significantly greater wingbeat frequency than is normal for a Pileated Woodpecker but matches the known wingbeat frequency for the Ivory-billed Woodpecker.

Despite the divergent viewpoints on how the Luneau video should be interpreted, all parties agree that it is vital to continue the conservation efforts begun in Arkansas, to restore habitat that is essential not only to the ivory-bill but to the many other species that rely on this unique ecosystem. Read more in the Cornell Chronicle.

Click on the links below to read either the abstracts or full text of the articles published in Science. These links are provided courtesy of Science magazine.

Comment on "Ivory-billed Woodpecker (Campephilus principalis) Persists in Continential North America," by David A. Sibley, Louis R. Bevier, Michael A. Patten, and Chris S. Elphick


Full text

Response to Comment on "Ivory-billed Woodpecker (Campephilus principalis) Persists in Continental North America," by John W. Fitzpatrick, Martjan Lammertink, M. David Luneau, Jr., Tim W. Gallagher, and Kenneth V. Rosenberg


Detailed analysis of the Luneau video.