Searching for the Ivory Bill

Searching for the Ivory Bill

Sara Barker and a team of researchers find conclusive evidence that brings the ivory-billed woodpecker back from 'extinction'.

By Gerry Boyle ‰78


 
The under-the-radar planning also included federal agencies, among them the U.S. Fish and Wildlife Service. In this case, an extinct species would suddenly become an endangered species, with all of the associated need for habitat protection and land-access management. Would land have to be closed to the public? If so, how much and where? "What we wanted was a chunk of time before the announcement to actually develop this plan with the agencies,— Barker explained.

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The ivory-billed woodpecker search team convenes at dawn for another day searching the swamps of the Cache River National Wildlife Refuge in Arkansas.
But all of this hinged on the strength of the team's case. Was this the irrefutable rediscovery of the ivory-billed woodpecker? Or was it just one more tantalizing but inconclusive glimpse?

Five months of intense searching (quantified by Barker as 21,000 searcher hours) had yielded seven well-supported sightings of the ivory bill, 15 sightings in all. The team had located several cavities similar to those made by ivory bills and dissimilar to those made by pileated woodpeckers. Though all of the 17,000 hours of digital recordings had not been analyzed as this story was being written, scientists had singled out what they think are three instances of the distinctive "double-rap— ivory-bill knocking heard on the 1935 tapes.

For a visitor to the Cornell lab in June, acoustics expert Russell Charif played both the original recordings (recently retrieved from storage and digitized) and the new recordings on a computer used for spectrography. On the monitor the sounds showed as blips amid flat stretches. Lab staff, including Barker, hunched around the computer in rapt silence as they listened to what could be the second known recording of an ivory-billed woodpecker. The file played, emitting a blur of insect noise, the calls of other birds. And then a nasal call sort of like the sound of someone holding their nose and saying the word "kent.— The call is thought to be the birds' way of keeping track of each other in the forest. And the 2004 calls, from two locations, sounded to a lay birder's ear just like the call of nearly 70 years ago. "They're pretty similar,— Charif said of the two sounds. "And they're pretty similar quantitatively when we measure it on the spectrogram.—

The Cornell experts have not completely ruled out the possibility—albeit slim—that the calls were those of jays, seen in the area where the sounds were retrieved. Jays are mimics, after all. "But then you have to say to yourself, they had to learn this from something,— Barker said. "So does that mean ivory bills are there [making the calls]? We just don't know.—

But downstairs, more conclusive evidence was waiting.

In a high-tech studio, lab staffer Ben Clock loaded a digital file into a studio computer. The video began to play, at first showing a man in the bow of a canoe moving slowly through the coffee-colored waters of a tree-filled swamp. The camera was mounted on the canoe's thwart. The canoe moved slowly, and suddenly a large bird came into view from the left. It veered away and remained in view as it flew off between the trees.

"You have the black primaries and the white trailing edge [of the wing],— Barker whispered, intently watching the video screen.

The video was played and replayed. It was blown up and slowed down. It was enhanced for clarity, and with each refinement it became more and more clear. Barker confessed that she was a doubter until she heard Gallagher's impassioned firsthand report, then convinced beyond a reasonable doubt when she saw the video. "Even the people who were the most skeptical said, 'What else could it be?'— Barker said.