Ivory-bill Season Wraps Up

Elusive ivory-bills leave more tantalizing clues, no hard evidence

By Pat Leonard

Mosquitoes and cottonmouths reign once again in the Big Woods of eastern Arkansas. Leafed-out cypress and tupelo, standing shoulder to shoulder, effectively put blinders on anyone hoping to see into their depths. So ended the 2005?06 field season and the search to relocate the Ivory-billed Woodpecker.

The crew posted this reminder on the door to the field house.

Photo by Bill Holiday

The bottom line is the old "good news-bad news" scenario. Yes, there were possible visual encounters and sounds that could have been made by an ivory-bill. No, there is no new video or photograph showing the bird in all its glory.

"We're pretty sure that there is not a resident pair of ivory-bills, as we were hoping, in the Bayou de View region," said Ken Rosenberg, the Lab's director of Conservation Science. With more than 550,000 acres of forest, however, ivory-bills could still be elsewhere in the Big Woods. "We had enough tantalizing sounds and possible encounters that we still have a lot of hope that there might be a pair—especially in the White River area," said Ron Rohrbaugh, director of the Lab's Ivory-billed Woodpecker Research Project. The ivory-bill, he said, is a highly mobile species, and the area is sizeable. About 72,000 acres have been searched—just 13 percent of the total habitat available in the Big Woods.

Volunteer Andrew Mackie from New York Audubon listens for the ivory-bill.

Photo by Sara Barker/CLO

The search team ranked each possible encounter with an ivory-bill according to its quality. There were 14 possible encounters from November 2005 through April 2006. Ten of them were glimpses of birds that witnesses said gave them an impression of something different from the superficially similar Pileated Woodpecker. These were ranked as "low probability" because no field marks were identified. The remaining four encounters were reported by a volunteer and three members of the public. In each case they saw one field mark: a broad band of white on the trailing edges of the bird's wings while it flew (two observations) or a broad band of white on the lower part of the folded wings of a perched bird. Such encounters, with one field mark clearly observed, are strongly suggestive of Ivory-billed Woodpecker but still cannot be considered definitive.

On a number of occasions, searchers heard possible kent calls and double raps that are characteristic of the ivory-bill. Some of the double-raps were recorded on videotape and are being analyzed now to confirm whether or not they match ivory-bill sounds.

"It's not as straightforward as you might think," said search team scientist Martjan Lammertink. "We have to exclude other sounds. We also do not have a confirmed recording of an ivory-bill double knock so we have to make inferences from recordings of other related woodpeckers. It's a complicated process." The team also found 28 cavities that are the right size and shape for an ivory-bill nest or roost hole.

Search efforts will continue next season but will be scaled down, relying heavily on volunteers. Remote time-lapse digital still cameras will continue to be part of the arsenal, along with autonomous recording units to capture sounds in the forest. The Lab's team will work closely with other states to search 18 priority sites within the historical range of the ivory-bill, providing training, equipment, technical expertise, and staff to help conduct these first-ever systematic surveys.

Volunteer Martin Piorkowski helped search the Cache River area.

Photo by Larry Newman/CLO

More than 130 volunteers and professional staff joined the search last season—some of the best field biologists and birders in the nation. They were unfailingly focused, enthusiastic, and dedicated. Much good conservation work has been accomplished by The Nature Conservancy, Audubon Arkansas, and others. Welcome attention has been focused on saving the unique ecosystem of the Big Woods and the many birds and animals that inhabit its green corridors. As Rohrbaugh notes, "We're still in high gear, we're still going to keep searching."

For more information about the search for the ivory-bill, please visit www.birds.cornell.edu/ivory.

For permission to reprint all or part of this article, please contact Laura Erickson, editor, Cornell Lab of Ornithology, 159 Sapsucker Woods Rd., Ithaca, NY, 14850. Phone: (607) 254-1114. email: lle24@cornell.edu