KTHV Ivory-bill story

KTHV (Little Rock) ran an Ivory-bill story yesterday. The video is here.

The video opens with Penny Childs of Penny's Hair Care saying "You either believe or you don't", with the anchorman then saying "Either way, the Ivory-billed Woodpecker means more millions for Arkansas".

At the end of the segment, they show some preliminary poll results. The question was "What do you think about the federal goverment spending $2 million on the Ivory-billed Woodpecker"?

These results were shown:

Money well spent--33 votes

Waste of tax money--292 votes

Woodpecker doesn't exist--49 votes

John Acorn's Grail Bird review

Bird Watcher's Digest has published John Acorn's review of The Grail Bird here (the bold font is mine):

...Yet careful analysis of the footage resulted in a paper in the prestigious journal Science, placing the stamp of academic approval on the rediscovery. (Although I have to remind you, here, that Science's biggest competitor, Nature, published a great-looking photograph and scientific description of the Loch Ness monster back in the 1970s.)
...
And what about Gallagher's frequent analogy between the ivorybill and Bigfoot? Let's face it, if this were Bigfoot, there is no way that anyone at Cornell University would have accepted the measly evidence, and no way that we would be seeing a major conservation effort to save the species. Gallagher's stories tell of grueling interrogations by skeptics, and the successful sightings that passed these tests, but the book never mentions the fallibility of human perception and memory.
...
...But a manager with the National Wildlife Refuge system told me that from their perspective the big mystery is why so few birders have come to Arkansas up to now. Perhaps we all have our doubts.

For me, the rediscovery of the ivorybill has been an emotional ordeal. I find the story of its decline dark and depressing. On the other hand, I find Gallagher's take on the rediscovery elating, but only if I don't think about it too terribly much.

After the end of the review, this information about Acorn is provided:

John Acorn is a biologist, writer, broadcaster, and university lecturer living in Alberta, Canada. He is best known as the host of the television series Acorn: The Nature Nut.

Non-believers on the KATV website

A story about Brinkley's Ivory-Billed Woodpecker Celebration was posted on the KATV (Little Rock) web site last night.

Judging by the viewer comments currently available here, it seems that the locals may not be completely convinced by Cornell's Ivory-bill rediscovery claim.

Comments on Cornell's abnormal Pileated page

An anonymous source emailed me the following:

Some comments on Cornell’s aberrant Pileateds and webpage…

"The white woodpecker was first seen on February 7, 2006, by Keith Brady during a two-week volunteer assignment with the crew of Tom Snetsinger. Video documentation of the bird was obtained by Sonny Bass (also a volunteer) on February 8 and by Utami Setiorini on February 13, and stills were made by Martjan Lammertink on February 13. Upon close inspection, the woodpecker has a few small areas of darker feathers visible on the face, hind-neck, and wing coverts (see photos above and at right)."

Found, refound. Photographed, videoed, rephotographed and videoed. Many good looks, many people, definitive proof. This bird had an extremely small population (one) but there was infinitely more solid evidence produced of its existence than by all the IBWO searchers in the world in the last 6 decades. And for those who use the “huge home range” excuse, I would point out that if the IBWO has survived there must have been hundreds of individuals and hundreds of nests in the last 60 years. And nesting Ivory-Bills are loud, conspicuous, and anchored to one spot.

"Documentation of this nearly all-white Pileated Woodpecker, as well as a second Pileated Woodpecker with an unusually large amount of white on its primaries, shows that these striking birds could not have been mistaken for ivory-bills."

False. Normal Pileated woodpeckers are frequently mistaken for Ivory-Bills. Cornell briefly mistook a normal pileated for an Ivory-Bill because of reflection of sun off its secondaries. Brief sightings of Pileateds with extra white on the wings could easily be the source of the "Ivory-Bill" sightings, if the sightings were brief and incomplete, as they all were.

Also, they admit there were AT LEAST two more Pileateds with extra white on the wings. Isn’t it an amazing coincidence that this stunning "Ivory-Bill rediscovery" occurred in the area in which three or more aberrant Pileated woodpeckers have been sighted? Wouldn’t it be rational to insist on at least ONE clear photo, or the Sibley standard of "Redundancy. Repeated sightings by independent observers of birds really well seen." ? NOT ONE “Ivory-Bill” was seen well by anyone!

"The search crew easily identified the white woodpecker as a Pileated Woodpecker. It behaved and sounded like a typical Pileated Woodpecker and moved in a loose association with two normally plumaged Pileated Woodpeckers, a male and a female."

In most ways, Cornell's "Ivory-Bills" did not behave and sound like Ivory-Bills. They have not traveled in pairs, as Ivory-Bills normally do. There have been no reports of loud wing noise, which is characteristic of IBWOs. The birds were not observed while calling or drumming. Cornell's modern IBWOs are nearly impossible to observe.

"In our view, the presence of a mostly white Pileated Woodpecker in the Big Woods is immaterial to the evidence supporting the rediscovery of the ivory-bill."

Really? So why the spin page concurrent with the announcement?

And were the suppressed photos and accounts immaterial also? Despite the fact that this was a central point in the debate, Cornell didn't "come clean" until now. Have we seen all the evidence they have now, or not?

"In fact, despite persistent rumors to the contrary (Jackson 2006), we are still unaware of any photographs or specimens of a truly “piebald” Pileated Woodpecker that could potentially be confused with an ivory-bill. A possible exception is a bird observed and described by Noel Snyder in Florida."

A POSSIBLE exception??? "Had the bird flown on immediately after I detected it, I would have been forever sure that I had seen a living Ivory-bill." And how about the Fred Collins birds? “In the 70s there was a partially albino Pileated Woodpecker that was very much patterned like an Ivorybill. It required a visit. Already since the Arkansas sighting another bird like this has been reported in Baytown. Fortunately with the use of Internet birdcalls, this Baytown bird was identified as a Pileated without a trip to the home. These birds demonstrate that plumage alone will not assure you that you are tracking an Ivorybill. Calls are not a sure bet either.”

In their original paper Cornell said this: "We are unaware of any examples of extensively and symmetrically pibald pileated woodpeckers in museum collections or the literature." They didn't investigate alternate explanations very well, because apparently they didn't know about Noel Snyder's bird. And if Collins is correct, the Texas bird in the 70s and the one from 2005. And that's just the ones "in literature."

And if you need photographs or specimens to prove a bird exists, Cornell is in big trouble.

"Fitzpatrick et al. (2005) argued that if such an aberrant Pileated Woodpecker was present there, it should be seen and re-found without difficulty."

Real birds can be found and photographed, imaginary birds can't. So far they have photographed at least three aberrant Pileateds.

"any leucistic Pileated Woodpecker present in the vicinity of our ivory-bill sightings and video in spring 2004 would be regularly seen and heard in the same area, as this area has been intensively monitored almost continuously since March 2004. "

So where are the IBWOs?

"What I did state to several individuals is that I made three separate sightings on different days of a Pileated Woodpecker that had an abnormal amount of white on the dorsal part of the wing when folded in the Bayou de View study area. I do not know if this was one woodpecker that I just happened to observe three times or three different birds. Given the number of Pileated Woodpeckers (typically 10-20 per search day) I saw at Bayou de View last year, it seems unlikely it was the same bird."

So one person saw at least one, and probably two or three aberrant Pileateds.

Question, if he had so many of these sightings, how about all the other dozens of people on the Cornell team? They said Pileateds were so easy to see and document, right? So several other searchers saw Ivory-Bills but not these aberrant Pileateds? What’s the explanation? Could it be the other people did catch brief glimpses of these birds?

"In short, despite our concerted efforts to find any, we have no evidence of leucistic Pileated Woodpeckers in this region of the Big Woods."

Just the one white one and who knows how many other aberrant Pileateds.

"Reports of other odd-plumaged Pileated Woodpeckers with “extra white” in the Cache/White River study area have persisted since our announcement of the rediscovery in April 2005."

The reason that they persisted is because they were true. If the Cornell Lab of Ornithology wants to claim scientific objectivity, they should have laid all the relevant facts on the table from the beginning, and let other scientists decide for themselves what the facts show.

New Cornell web page on abnormal Pileateds

Now available here.

More federal money for the Ivory-bill?

Check out this press release.

Note that this announcement is to be officially made by Interior Deputy Secretary Lynn Scarlett at 1pm tomorrow in Brinkley, Arkansas. This time and place was evidently chosen to coincide with the three-day "Call of the Ivory-billed Woodpecker Celebration" which starts today.

This event has been billed as a "Re-Birthday Party" to celebrate the 2nd anniversary of the February 27, 2004 "First Confirmed Sighting of the Ivory-billed Woodpecker in 60 years".

"Latest" updates from Gene Sparling

In recent weeks, under "Latest Updates on the Ivory-billed Woodpecker", The Nature Conservancy has posted two field notes from Gene Sparling here.

Curiously, at the beginning of each field note, there is a paragraph indicating that these notes are actually at least two years old:

Editor's note: What follows is one of the first journal entries Gene Sparling made when he began exploring the Big Woods of Arkansas — before he encountered the elusive ivory-billed woodpecker on Feb. 11, 2004.

Thanks for visiting

According to sitemeter.com, this blog has just received its 100,000th page view (and about 34,000 visits to date).

I'm aware that a healthy portion of that traffic is from people who disagree with virtually everything I say, but I'd like to say "thanks" just the same.

Email to Jerome Jackson

An anonymous person forwarded me a copy of an email (below) that he recently sent to Jerome Jackson.

Please note once again that those are not my words. For better or worse, in recent weeks I've been receiving an increasing number of emails with a similar skeptical message and harsh tone--for many, it seems that Cornell's online Luneau video analysis may have been "the last straw":

Dear Dr. Jackson,
Your recent article in The Auk 'Perspectives' shines as a courageous and heroic example for all. I agree with your ornithological and political analyses 100%. Your exposition is thoughtful, well reasoned, thorough, objective, factual and well supported by the documentary and historical evidence. In brief, your article stands in stark contrast to the self-aggrandizing, wholly unsupportable, unsupported, and self-contradictory claims of those who wrote that they have proof that the Ivory-billed Woodpecker persists in continental North America.

As a life-long birder with 40+ years of field experience, I doubted the purported claims of "rediscovery" from the moment they were first disseminated. The data put forth is simply not proof of IBWO existence; indeed most of the data upon analysis actually confirms Pileated Woodpecker was observed, not IBWO.

I am outraged, as should all birders be, by the secretive, deceptive, and purposefully exploitative tactics and strategy of Cornell, TNC and USFWS in this matter. Sadly, the subsequent, highly selective releases of data by Cornell, TNC and USFWS to further their own ends, serve only to further discredit those institutions and to insult the public. In total, their statements prove not IBWO existence, but rather misidentification and misrepresentation, whether deliberate or otherwise. The latest egregious example is the Cornell web page of so-called "detailed analysis" of the Luneau video, purporting to show why the bird in the video is an IBWO. In fact, the comparison even to a layman actually reinforces the fact that the video shows an ordinary Pileated Woodpecker. I am angered that public funds and attention are being diverted from truly useful projects to protect endangered a! nd threatened species and habitats.

The majority of serious birders who are willing to discuss the topic with me are privately in agreement with your paper. But they are afraid to speak out.

Dr. Jackson, since I began birding as a kid, five heros inspired me in ornithology: John James Audubon, James Tanner, Roger Tory Peterson, Rachel Carson and Chan Robbins. Now, after four decades, I have a sixth hero. I was fortunate to meet Peterson, Carson and Robbins in person. I hope I can meet you some day too.

Congratulations on a fine article and a courageous, inspiring spirit.

Updated Luneau video analysis

Cornell's detailed Luneau video analysis is now available here. Cornell's summary lists nine "diagnostic traits" that lead them to believe that the Luneau bird is an Ivory-billed Woodpecker.

I disagree with Cornell on all nine points--I see nothing in that video that is inconsistent with a completely normal Pileated Woodpecker.

Below, I've listed each of Cornell's points, followed by my opposing viewpoint:

(1) The underwing pattern in flight consistently appears largely white, giving the appearance of having black wingtips but lacking any black along the rear, or trailing edge.

In many frames, both underwings do appear to have trailing black edges.

Here is an example:

Note that in Cornell's paper, they state: "With these distances and light conditions, bleeding tends to exaggerate the apparent extent of white in the wings." I think this explains the faintness of the trailing black underwing edges.

(2) The upperwing pattern in flight consistently shows a broad, white trailing edge, with no frames demonstrating the conspicuous dark rear border to be expected of normal Pileated Woodpeckers.

I think we are seeing the bird's underwings, not the upperwings. The pictures here show that a fleeing, normal Pileated shows a lot of flashing white underwing, both when the wings are above horizontal and when the wings are below horizontal.

In support of their point #2, they inexplicably show us a video of a Franklin's Gull, flying away in a leisurely fashion. This is supposed to "prove" that a fleeing Pileated's dorsal wing surface should be prominently visible when viewed from behind.

This comparison makes no sense to me. Instead of admitting that their stiff-winged Pileated re-enactment model was seriously flawed, they went far afield to find a species where a stiff-winged model might have been more reasonable.

(3) The wings are longer relative to the body diameter than in Pileated Woodpecker and consistent with the wing shape of Ivory-billed Woodpecker.

I'm completely unconvinced that you can accurately measure wing length, much less body diameter, from this low-quality video.

(4) Reenactment of the scene using life-sized, realistically painted, dynamically flapping models produced images remarkably similar to those of the Luneau video using the Ivory-billed Woodpecker model, and images clearly identifiable as Pileated Woodpecker using a model of that species.

Cornell posted this picture of the reenactment models:

These models are fatally flawed in that their stiff, board-like wings simply can't be made to fly like the Luneau bird. (In addition, the smooth surfaces of the models may reflect light differently than the feathers of an actual bird.)

(5) The wingbeat frequency is 8.6 beats per second, which is almost identical to that recorded for Ivory-billed Woodpecker (as documented by one acoustic record from 1935). The wing-beat frequencies of Pileated Woodpecker are not known to exceed 7.5 beats per second, and more typically range between 3 and 6 beats per second.

The above argument is countered by information from a comment here:
----
This really is unconvincing. They record a wing-beat hz at 8.6 and compare this to their records of 2-4 beats level flight "and 4-7.5 beats for short periods during hasty departures (n = 5)". "Moreover, experts who have studied Pileated Woodpecker flight using video analysis timed the fastest departures at 7 beats per sec (Tobalske 1996, personal communication). Thus, wingbeat frequency of the woodpecker in the Luneau video is faster than any recorded Pileated Woodpecker".

A sample size of 5 is nowhere near big enough to rule out a Pileated being able to do 8.6, whilst the Tobalske reference (paper published in Auk) is one study where "nonmaneuvering flights with approximately no change in mean altitude were included in the sample". The paper specifically did not look at flapping flight of fleeing woodpeckers. Thus the sample size of fleeing Pileated flights is tiny.

To then try and suggest that this ties up well with the sound recording of an Ivory-bills wingbeats (sample size = 1) is equally flimsy.
----

Also note that the Luneau bird's wingbeat frequency slows significantly after the initial flaps.

(6) White plumage on the back is visible on the retreating bird as it begins to gain altitude. Ivory-billed Woodpecker has white on the back; Pileated Woodpecker has entirely black back.

I think Cornell completely misinterpreted the position of the bird; my explanation is here.

(7) The dorsal view of the right wing as it begins to unfold shows a triangle of white that matches in size and position the white on the folded wing of an Ivory-billed Woodpecker beginning to launch into flight.

I think there are at least two problems with this argument.

1. Below is the inset sketch from Cornell's paper, followed by an Arthur Allen (1935) photo of a perched Ivory-bill. On the folded wing, note that the white patch on the inset sketch is much more extensive than on the Allen photo; also note that the shape of the white patch differs between the sketch and the photo.

2. Let's carefully consider the Luneau bird's movements during the 10-frame "launch sequence". I would argue that Cornell's "folded wing" theory is an extremely poor fit for the contents of those 10 frames.

For this discussion, let's call field 33.3 (the point of maximum wing flash) Frame 0. Note that at about 60 frames per second, the spacing between frames is about .0166 seconds. We know that at Frame -2, the bird's body is completely hidden by the tree; by Frame 7, the bird's right wing appears on the right side of the tree--the bird is in full flight, evidently well away from the tree, with the right wing near the top of the upstroke.

Under Cornell's theory, in response to the approaching canoe, the Luneau bird lunges powerfully to its right (our left), flashing a lot of folded wing within two frames (.033 seconds), but ending with its head still fully behind the tree (as pictured in Fitzpatrick's inset sketch above). The bird then immediately checks its momentum and lunges powerfully to its left (our right), with its wing still almost entirely folded by Frame 1.

Now we need to consider what the bird was doing behind the tree, between Frames 1 and 7. I would argue that according to Cornell's "folded wing" theory, the bird is now caught "between flaps". The Luneau bird takes about 7 frames per wingbeat. When we see the right wing held high in Frame 7, is that the first or second time that the wing was in that position? If it's the first, why did the wing open so slowly, and how could the bird possibly have lunged so powerfully? If it is the second, how did the Luneau bird complete a wingbeat cycle within about 3-4 frames? (Note that if the wing was just opening in Frame 1, it likely wouldn't be fully raised until Frame 3 or Frame 4, leaving it only 3-4 frames to complete one full wingbeat cycle by Frame 7).

I think the folded wing theory makes no sense. I think Jackson's "fully opened wing" theory is a much better fit. Under that theory, in response to the approaching canoe, the bird doesn't need to lunge violently right and left--it simply launches as normal, raising its wings and completing one wingbeat cycle in the normal 7 frames.

Below is a blown-up section of Field 33.3 from Cornell's paper; I think it is more correctly interpreted as the underwing of a normal Pileated Woodpecker as shown.

Note that under my interpretation, the black border to the left of the white blob is the black trailing edge of a normal Pileated's underwing.

Cornell rejects the "vertically held underwing" hypothesis for two reasons.

First, they claim that the "tail of the woodpecker is still pointed down vertically in Field 33.3, meaning that the body of the woodpecker is perched vertically at this moment". I'm unconvinced that the woodpecker is perched vertically in Field 33.3--for one thing, the black smudge that Cornell interprets as the bird's tail is still visible on the tree even after the bird has flown away. A black smudge does appear to the left of the tree in Fields 50 and 66.7--this appears consistent with a Pileated's tail, extending out and to our left as the bird launches from the far side of the tree, then turns to its left to flee.

Second, they attempt to rule out a Pileated's underwing via a precise calculation of the width/length ratio of the white patch in Field 33.3. I think this ratio cannot be accurately calculated from such a low quality video, especially since they admit that "...bleeding tends to exaggerate the apparent extent of white on the wings".

You can read more about Field 33.3 here.

(8) The distance between the wrist area and the tip of the tail (32-36 cm, as measured when the bird begins to take flight) is comparable to known measurements of Ivory-billed Woodpecker and considerably larger than even the largest Pileated Woodpecker we measured.

See (7) above. I think Cornell's wrist-to-tailtip measurement is meaningless, since they've completely misinterpreted the position of the bird's right wing.

(9) Only 20 seconds before the woodpecker flees, a bird with the size and color pattern of an Ivory-billed Woodpecker was perched within 3 m of the site from which the woodpecker took flight.

There are many candidate "six-pixel Ivory-bills" at various places in the Luneau video, and I think that all of them are just artifacts of an unfocused camera. Here are some of them:

According to Jerome Jackson, John Fitzpatrick admitted that the "six-pixel bird" in Cornell's paper is a likely a branch stub.

================================================
Some other notes and observations:

A) Regarding flight style:
Note that James Tanner said "In flight the Ivory-bill looks surprisingly like a Pintail".

In my opinion, the Luneau bird's flight style is nothing like a Pintail; in fact, the Luneau bird's flight style is completely consistent with a Pileated Woodpecker.

Compare the Luneau bird's flight style with this known Pileated (Cornell's Clip 11), and then compare it to this Yellow-billed Pintail video.

(Note: The Pintails are not in powered flight throughout the entire video. However, the video shows a few flaps of powered flight as the birds fly to the left against a headwind, and it shows more powered flight as the birds turn to the right and fly away from the camera.)

Below, I've sketched the wingbeat cycle of a fleeing Pileated, with the downstroke on the left and the upstroke on the right. Note the acute angle of the wings at the top of the upstroke, and note how far the wingtips extend downward on the downstroke. On the upstroke, note how the wingtips are pulled closer in toward the body.

In contrast, note that a Pintail's wings in powered flight are held relatively flat, with the wingtips held fairly equidistant from the body at all times. Note also that the wingbeat is quite "shallow", with the wingtips never positioned very high or very low relative to a horizontal position.



B) If the Luneau bird is an Ivory-bill, then where is the black underwing line? Note that Cornell provides this intentionally-blurred Ivory-bill picture, but you can still see the black underwing line:



(Yes, I know that the "white bleeding" argument has been used to explain the absence of the black underwing line in the Luneau video. The black trailing edge of a Pileated's underwing seems to be visible in many frames showing the flying bird, and it also appears to be present in Cornell's figure S1 [see point 7 above]; however, in no frame do I see any hint of a black underwing line.)

C) Here's what Tim Gallagher says about the Luneau video in "The Grail Bird", pages 224 and 225 (the bold font is mine):

In the blown-up film, I could see what appeared to be a large bird with a black-crested head and a white bill peering out from behind a tupelo...I was completely floored. Virtually all of the ivory-bill's major field marks were there, albeit fuzzy.

Gallagher is listed as one of the author's of Cornell's online Luneau video analysis. Which frame(s) show the black-crested head and white bill?

D) Questions about the Luneau audio are here.

E) You may be interested in some more Luneau video analysis sent in by readers--a composite picture here, an analysis of the Luneau bird's underwing here, and some "red dot analysis" here.

Beyond spin

The excerpt below appeared in an article in Sunday's Minneapolis Star Tribune (registration may be required; the bold font is mine):

Other evidence included nine additional sightings and more than 100 recordings of what researchers believe may be ivory-bill sounds.

Even those most skeptical now agree the ivory-bill exists in Arkansas. Three scientists had announced they were producing a paper refuting the evidence; after being provided a response prepared by Cornell and other scientists and after hearing some of the best recordings, two of them withdrew their paper.

One was quoted in the New York Times as saying, "The thrilling new sound recordings provide clear and convincing evidence that the ivory-billed woodpecker is not extinct."

He said he was "strongly convinced that there is at least a pair of ivory bills out there."

The article's author is Ron Nargang, state director of the Nature Conservancy in Minnesota. The New York Times quotes were attributed to Richard Prum in an August 1, 2005 article.

I think it's preposterous to claim Richard Prum as an Ivory-bill believer as of February 2006. He's been publicly skeptical for months, as shown here, here, and here.

Analyzing the Luneau bird's underwing

From an anonymous source:

To supplement what has been posted earlier by yourself and others, this is my take on just four frames from the Luneau video:

Because I think the pattern of the underwing is the most diagnostic feature in the video, I chose the four frames which show the underwing the best. Please note that I didn't choose or reject frames to illustrate my point, I simply chose the four "clearest frames" of the upraised wings.

Along the left side of the composite are the four frames showing the Luneau bird with upraised wings, flying to the right, with the white being the underside of the right wing. On the right side of the composite, at the top, is a frame from a Tanner/Allen film of the 1930s showing a known Ivory-Bill. On the bottom is one of Cornell's blurred Pileated frames. The two black and white drawings are images from the original Cornell Paper from last spring. The upper is a Pileated and the lower is an Ivory-Bill.

As the Cornell drawings show, the underwing of both birds is largely white with a black wingtip, with the major difference being that the Pileated has a black trailing edge, while the Ivory-Bill has a black stripe through the center of the wing.

To my eye, the Pileated frame is virtually indistinguishable from the Luneau frames, and would be an even better match if it were angled exactly the same. I can see the black wing tip, the white underwing, and what may or may not be a black trailing wing edge. I see these same features in the Luneau video AND the Pileated video.

Furthermore, in none of the Luneau frames do I see any indication of the black stripe that runs through the center of every Ivory-Billed wing. It is not the AMOUNT of white that is diagnostic, it's the PATTERN of the black and white.

I also think Cornell's point about the narrow wing shape of the Ivory-Bill (as shown in the top, right frame) actually works against them. To my eye, each of these four frames shows what appears to be a shorter, more rounded wing, much more like a Pileated than an Ivory-Billed.

In short, I agree with Kaufmann, Jackson, Sibley, Prum and others; the Luneau video probably shows a normal Pileated Woodpecker.

Prum quoted in The Independent

Below are some excerpts from an article today in The Independent (the bold font is mine):

"It was the first time two qualified observers had seen the bird simultaneously since 1944," Gallagher. explains "That made a difference. And I'm a conservative birder. I've never made a bogus call."
...
"There are a lot of reasons to believe the ivory-bill woodpecker is an extinct species," says Richard Prum, who is the curator of ornithology at Yale University's Peabody museum.

"All of the proffered evidence, and there is not a lot, is incomplete and inconclusive," Prum tells me when I speak to him by telephone. "All of the people who have seen it fleetingly are true believers and magical things happen to true believers."

Prum claims there is no scientific reason why the bird should not be able to be found, if it is alive, and that with so many people searching the area, it could not avoid detection indefinitely. "If these people haven't produced irrefutable evidence by the end of the field season in April, then they will have a lot of explaining to do," he says.

Harrison has his own theories as to why the bird is proving so elusive: "I think there are too many people searching at this point," he says. "This is a very wary bird and so going from the hotel to the swamp every day and visiting doesn't work. I think you have to live out there for a while. Also the area is so huge."