IBWO: It may be extinct

Less than a month ago, I thought the Ivory-billed Woodpecker was definitely alive and well in Arkansas. As I continue to examine the available information for myself, my doubt is growing. Like just about everyone else, I *want* the Ivory-bill to be alive, but I think we need to face a very real, very unpleasant possibility: the last one may indeed have died many years ago.

Let's start here, on the official Ivory-bill site:
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The team reported multiple fleeting views of the bird, a frame-by-frame analysis of two seconds of video footage, and possible recordings of the woodpecker’s distinctive double knock. This evidence has convinced many that at least one ivory-billed woodpecker survives in the Big Woods of Arkansas’ Mississippi River Delta.
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To me, the wording above suggests a certain lack of conviction, even by "insiders".

Look at this article:
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Finally, to put your chances in perspective, we logged more than 20,000 hours of searching for less than one minute of total Ivory-bill observation time.
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Ok, so somewhere between 8 and 18 sightings added up to less than one minute in total observation time. Those views really were fleeting--if you do the math, that would be an average of about 3-7 seconds per sighting.

According to Cornell's Supporting Online Materials, as of March 2005, all of their sightings had been clustered in four square kilometers of forest. According to my reading of the "The Grail Bird", those sightings occurred in this area. The vicinity was combed endlessly. It was monitored with numerous remote audio recording units as well as remote still and video cameras (with decoys). Tape playback and an elevated boom were employed. Despite this truly massive effort, not a single good view or photo was obtained.

Now why would there be 8-18 fleeting sightings, but zero non-fleeting sightings? Maybe the reason is that, to an experienced birder, a leucistic Pileated Woodpecker can only pass as an Ivory-bill if the look is fleeting. On a distant flying bird, birders would logically have a search image something like this: "level flight, dark bird with trailing white on the wings". If the bird is distant and your glimpse is truly fleeting, even birds like an American Crow with white wing patches, a Red-headed Woodpecker, a Wood Duck, or a Hooded Merganser could fit that search image. This could be especially true if you knew that other credible birders had reported Ivory-bill sightings in the area.

It's important to remember that many of the birders behind Cornell's "convincing sightings" were not 100% sure themselves that they had seen an Ivory-bill. In the "Grail Bird", Tim Gallagher wrote: "I was annoyed that so many people were throwing out percentages about how sure they were that they had seen an ivory-bill. Ron and David were maybe 85 percent sure; Jim Fitzpatrick was 98.5 percent sure; now here was Mindy saying she was 99 percent sure of her sighting."

No acceptable photographs have been taken in many decades. Some say the reason is that the Ivory-bill is so wary. However, in the 1930s and 1940s, the Ivory-bill was very rare but was not particularly wary, and many good photographs were taken.

If you're interested, take some time to read the information here. Written by Arthur Allen and P. Paul Kellogg, it details observations of Ivory-billed Woodpeckers in the 1920s and 1930s. With only a handful of team members, in an 81,000 acre swamp, they were able to locate several nest sites, take lots of clear photographs, and hang around the nests as the birds went about their lives. In the accounts of those days, I do see cases where a small team sometimes searched for a few days without success. Far more commonly, I see cases where they searched hard for a day or two, heard the call, located a roost, and then enjoyed repeatable good looks at the birds.

In the current hunt, we have a much larger team of experienced birders searching for over 20,000 hours. That effort would roughly equal a team of 15 people searching 10 hours a day, 10 weeks a year, for 2 years. Again, despite all the modern advantages mentioned above, not a single good view or photo was obtained.

If the Ivory-bills are really out there now, why have the massive search efforts in recent decades been so spectacularly unsuccessful? Have we completely lost our ability to find Ivory-bills, or are we searching for something that simply isn't out there?

As a thought experiment, let's try this. Imagine a large 160,000 acre tract in Arkansas with some good Ivory-bill habitat. Let's imagine that during the experiment, we somehow know that no Ivory-bills are present. Turn a rotating team of 15 enthusiastic, experienced, honest birders loose in that tract, and have them spend over 20,000 hours over a couple of seasons in an effort to find Ivory-bills.

Q. Would I expect them to get some fleeting glimpses of birds that might be Ivory-bills?
A. Absolutely. In an area that size, with that much coverage, I would expect some glimpses of leucistic Pileateds (and other species) that seemed very Ivory-bill-like.

Q. If they gathered 17,000 hours of audio data, would I expect them to find some sounds with sonograms that appear to match the Ivory-bill's distinctive "kents" and "double-knocks"?
A . Absolutely.

Q. Would I expect them to gather any acceptable photographs, or get any long, repeatable good looks at Ivory-bills?
A. No.

IBWO--audio evidence NOT conclusive

It seems that this New York Times article was the clincher for many people--at last, we've got audio proof that the Ivory-billed Woodpecker lives!

That made no sense to me. As it turns out, I'm not alone. (I added the bold font that you see below).

1. M. David Luneau (who took the disputed Ivory-billed video) posted this yesterday on the Arkansas Birding Listserv:
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The sound recordings that have been referred to in recent news reports are still being analyzed. It is premature to assume that they are recordings of IBWOs as reported in the press, as that conclusion has not been reached by everyone involved.
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2. Yesterday on that same listserv, a news release was posted from the U.S. Fish and Wildlife Service, Southeast Region. Here's a snippet:

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The U.S. Fish and Wildlife Service said today it plans no changes at this time to public use management at the White River National Wildlife Refuge in eastern Arkansas.

This announcement comes on the heels of yesterday's news that three scientists are withdrawing a paper expressing doubt about evidence of the rediscovery of the Ivory-billed Woodpecker. Their decision to withdraw the paper is based on a sampling of sound recordings taken from White River in January, 2005 that strongly suggest the presence of Ivory-billed Woodpeckers there.

These recordings are part of 17,000 hours of audio taken over the past 18 months at dozens of locations throughout the Cache and White River ecosystem. Findings from Cornell's research will be presented at the American Ornithologists Union meeting later this month in Santa Barbara, California. While Cornel's scientists and others are excited about the initial reports, only 20% of the recordings have been analyzed. Indeed, Cornell scientists emphasize that they cannot be 100% certain that the sounds were made by an Ivory-billed Woodpecker. The Service will continue to monitor the research activities in the area.
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Today, a New York Times editorial still says "It's indisputable". Moral: Don't believe everything you read in the New York Times.

Bread Crumbs

Last spring, Cornell announced that the Ivory-billed Woodpecker had been refound. Last week, I shared some of my thoughts about the lack of conclusive proof provided with that announcement. News reports named Richard Prum, Mark Robbins, Jerry Jackson, David Sibley, and Kenn Kaufman as skeptics.

Yesterday, a New York Times article says that Prum and Robbins now believe that new audio evidence proves the existence of at least two Ivory-bills. Based on that article, I'm now seeing Internet postings with headlines like "Everyone agrees; there are multiple IBWOs!"

I think it's much too early to state that *everyone* agrees. For starters, are Jerry Jackson, David Sibley, and Kenn Kaufman convinced by the new audio evidence?

I think it's very interesting that Prum states that he was very skeptical of the initial Ivory-billed reports, and that he still believes that the video shows a Pileated Woodpecker. The growing message seems to be "Ok, so the video and sighting evidence wasn't very strong. But look, now we've got irrefutable audio evidence!"

I'm wondering why audio evidence is suddenly considered so very credible. On Cornell's own web site, we still see a different view of audio evidence:

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If a clear, time-stamped photograph is irrefutable evidence that the Ivory-billed Woodpecker lives, then recorded sounds of Campephilusprincipalis--and not something else that sounds almost like it--are high-tech "breadcrumbs."
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"Think of these recorded sounds--the signature double-rap of the ivory-bill or its kent call--as bread crumbs leading a camouflaged photographer to the base of the tree for that once-in-a-lifetime photo."
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Audio evidence was also mentioned in Cornell's April Science report, but it sure didn't seem definitive back then:

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Double-knock sounds strikingly similar to Campephilus display-drums were recorded on several of the ARUs...We cannot positively associate these recorded signals as belonging to ivory-billed woodpecker, however, and several seem out of context. Series of nasal calls closely resembling those recorded by A. A. Allen at the Singer Tract in 1935 were recorded at two places in the White River National Wildlife Refuge, but these may have been given by blue jays (Cyanocitta cristata, a notorious mimic).
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Ok, so 24 automatic recording units were spread over 160,000 acres, and recorded 17,000 hours of audio. How can we be sure that the key recorded sounds came from actual Ivory-bills, rather than from some combination of distant gunshots, nuthatches, other woodpeckers, people playing Ivory-bill tapes, jays mimicking people playing Ivory-bill tapes, etc?

I agree with Cornell's web page--these sounds should only be used as high-tech bread crumbs, but never as standalone proof. Cornell said they've checked out the spots where the key audio was recorded, but have so far found no Ivory-bills.

The evidence to date consists mostly of sub-optimal sightings and some bread crumbs.

Based on my reading of the publicly available evidence, here are some questions and answers:

1. Do we have a good photograph?
Answer: No

2. Has anyone seen the underwing well enough to describe it correctly?
Answer: No

3. Has anyone seen the white dorsal stripes well enough to describe them correctly?
Answer: No

4. Has anyone seen the bird well enough to describe the white neck line that ends before the bill?
Answer: No

5. Has anyone seen the bird well enough to describe the pale bill?
Answer: No

Again, the David Sibley standard for proof is "redundancy. Repeated sightings by independent observers of birds really well seen." That is not too much to ask.

I truly hope that such proof will emerge sometime soon!