Audio Evidence of Ivory-Billed Woodpecker New evidence adds to hopes that the ivory-billed woodpecker, feared extinct, is alive in eastern Arkansas. Researchers have captured bird calls and rapping that reinforces video evidence of a bird in flight.
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Audio Evidence of Ivory-Billed Woodpecker

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Audio Evidence of Ivory-Billed Woodpecker

Audio Evidence of Ivory-Billed Woodpecker

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This is MORNING EDITION from NPR News. I'm Steve Inskeep.


And I'm Renee Montagne.

There's new evidence suggesting that the much-argued-about ivory-billed woodpecker is indeed alive in eastern Arkansas. The evidence consists of bird calls and woodpecker rapping. The ivory bill was thought to be extinct until scientists produced a videotape taken last year in an Arkansas swamp. The video was short and blurry and some experts weren't convinced it showed an ivory bill. The new sounds have persuaded at least some skeptics that the ivory bill is alive. In this NPR/National Geographic Radio Expedition, Christopher Joyce traveled to the laboratory of ornithology at Cornell University to listen to the new evidence.


The laboratory is on Sapsucker Woods Road in Ithaca, New York. There's a pond and a forest and enough birds around to fill the ark. Spotting scopes point out from just about every window. There's one room, though, with no windows. Here, computers and human experts are listening to more than 18,000 hours of recordings. The recordings were collected by devices planted on trees in the Arkansas swamp where the woodpecker was sighted last year. Ornithologist Russ Charif is in charge of this audio marathon. He recalls when a researcher heard the first hint.

Mr. RUSS CHARIF (Ornithologist): The ivory bill call, which has sometimes been described as sounding like a child's tin horn, `kent, kent,' we've fallen into the vernacular of calling them kent calls or kentlike calls, and she found this series of kentlike calls, and they sounded pretty darned good.

JOYCE: What they have is a short and faint series of calls. The first was recorded on January 17th in the White River National Wildlife Refuge. Over the following two weeks, they picked out four more calls. Here is one of them. You'll have to turn your radio up to hear it.

(Soundbite of bird calls)

JOYCE: Now let's compare that to the only know recording of an ivory bill. It was made in 1935 by a Cornell research team in Louisiana.

(Soundbite of bird calls)

JOYCE: That recording was made right underneath the birds. Charif points out that their recent Arkansas recording was obviously of a distant bird, so they expect it to sound a little different.

Mr. CHARIF: Certain frequencies will penetrate through the forest better than others. Probably the thing that affects that the most has to do with the distribution of tree trunks and limbs of different sizes that are reflecting and scattering different frequencies from the original sound. So it looks different and it sounds different when it's 140 meters away, which is not surprising.

JOYCE: It looks different because Charif turns each sound into a spectrogram. It's a visual display with the fundamental tone and its harmonics laid out like ink blots on a screen. Charif calls it an audio fingerprint. So the team had a verified 1935 recording of an ivory bill, close up, and their Arkansas bird calls filtered through the forest. They realized that to accurately compare them, they had to listen to the old recording under the same conditions as the new one. So they played the 1935 recording in the Arkansas forest. Here's what it sounds like.

(Soundbite of bird calls)

JOYCE: And again, here's the 2005 Arkansas recording for comparison.

(Soundbite of bird calls)

JOYCE: For John Fitzpatrick, the director of the Cornell lab of ornithology and the ivory bill project, it's a match, probably.

Mr. JOHN FITZPATRICK (Cornell University): When we get a recording of an ivory-bill woodpecker that's eight or 10 feet away yacking away on the trunk, I'm gonna be able to jump up and down and say, `That's an ivory-billed woodpecker.' The problem is, what we've got recordings of so far are of birds, unknown hundreds of meters away, that has sounds that are tantalizingly close, but once again, we're trying to be aware of the fact that we want it to be true. It's in our job to be as cautious as we can.

JOYCE: That means making sure the Arkansas calls were not made by something else, such as a nuthatch or a blue jay, both birds known to make nasal calls similar to the ivory bill's. In fact, Charif has recordings of blue jays in Arkansas.

(Soundbite of bird calls)

Mr. CHARIF: There's a crowd of blue jays, and some of them are making typical blue jay calls, but there's also these other sounds that are not typical blue jay sounds. They are more like an ivory bill than typical blue jay sounds. They are not exactly like ivory bills. So this doesn't solve the mystery.

JOYCE: The audio spectrogram of the blue jay calls does look different from the spectrograms of the 1935 ivory bill and the kentlike calls from Arkansas. Charif says an analysis by computer confirms that, but he says blue jays cannot be ruled out until they get more recordings of them from Arkansas.

The team also has another kind of audio evidence from Arkansas, dozens of double raps. The ivory bill and its living cousins in Central and South America, the genus Campephilus, all make a distinctly double rap or double knock. That's what ornithologists call a display call. Here's one from Central America.

(Soundbite of knocking sounds)

JOYCE: Cornell's devices recorded their first double rap in Arkansas last Christmas Day. There was just one by itself, but we'll repeat it to make it easier to hear.

(Soundbite of knocking sounds)

JOYCE: Again, John Fitzpatrick.

Mr. FITZPATRICK: These are just plain perfect double knocks. There's no specialists in American woodpeckers or birds would listen to this and not say, `That sounds a lot like the double knock of a Campephilus woodpecker.'

JOYCE: Weeks later, the team got another double knock recording. It was a pair of double raps, like a call and response, suggesting that there may be two birds. The acoustic evidence was presented for the first time yesterday to scientists at the annual meeting of the American Ornithologists' Union in Santa Barbara, California. The Cornell team says the evidence is suggestive and still isn't what they'd like it to be. The bird or birds are skittish and quiet, the video is short and blurry, and the audio recordings are faint. Ron Rohrbaugh and Sara Barker lead and coordinate the search team.

Mr. RON ROHRBAUGH (Cornell University): In terms of whether or not it's as good as a picture, it's great, but, boy, we'd love to have a nice 8-by-10 color glossy of this bird. I mean, that's concrete evidence that's almost irrefutable.

Ms. SARA BARKER (Cornell University): My greatest fear is that we may not be able to learn more about it to help protect the appropriate habitat for this species, and I just hope that we have a little bit of luck. We will discover maybe a roost hole or a nesting cavity.

JOYCE: Cornell's Ken Rosenberg, who runs the conservation program at the lab, says more people in the field will help, but it's still like assembling a puzzle while wearing a blindfold.

Mr. KEN ROSENBERG (Cornell University): At our first meeting of the recovery team, which we've had recently in Arkansas, we looked around the room, and there were 90 or so people involved. Not a single person in the room had ever seen one. So this idea that we're recovering a ghost or recovering a myth, you have to sort of overcome that with this group because it's unique and it's more than just unusual.

JOYCE: Team members say they're glad they're no longer working in secrecy, as they did for 14 months after the first sighting, although one of their recordings suggests the secret was not so secret. It captured a group of boaters in an Arkansas bayou who encountered one of the recording devices. It didn't take them long to figure out what it was and what it was for.

(Soundbite of recording)

Unidentified Man #1: See that red light blinking on it?

Unidentified Man #2: Yeah.

Unidentified Man #1: What is that?

Unidentified Man #3: They're looking for some kind of bird, a hoodoo bird. The ivory-billed woodpecker is what they're looking for. At least for the sound of it.

JOYCE: The search team returns to Arkansas this fall, and they'll be looking for volunteers as well as paid searchers to find that hoodoo bird again. For Radio Expeditions, I'm Christopher Joyce, NPR News.

MONTAGNE: Radio Expeditions is a co-production of NPR and the National Geographic Society. To hear the sounds of the ivory-billed woodpecker, go to

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