Why does the myth of surviving Ivory-billed Woodpeckers continue to be perpetuated? The only evidence that exists are a few eyewitness accounts, some holes in trees that are supposedly larger than the ones made by Pileated Woodpeckers, some recorded calls that might well have been made by Blue Jays, and a poor quality video that could easily be a Pileated Woodpecker with a lot of white on its wings.
By all accounts the Ivory-billed Woodpecker isn’t or wasn’t a very secretive bird, yet extensive searches in an area of only 100 square miles have never turned up anything except the aforementioned video. I have to think that the only reason people are willing to go along with this is because it provides a stronger argument for protecting that wilderness area, as noble a cause as that might be.
I doubt if I can convince you, and I’m not inclined to try, given your use of the word myth to describe what is actually a developing story. Have you read the various arguments concerning white patches on the wings of pileateds? As I read it, there are pileateds with 2 inch patches, the video shows much larger patches. One of the skeptics’ theories about the video involves wing twisting and seems pretty contrived. Wishful thinking can be pretty powerful, and it may be at work here. I’m inclined to feel some hope, and eagerly await further developments.
Like Crotalus said, this story is only in the beginning stages; the video and eyewitness accounts help, but don’t necessarily prove the case. More research is needed.
Have you ever been to the Big Woods in Arkansas? (it’s bottom-land hardwood forest in the basins of the White, Mississippi, Arkansas and Cache rivers). It’s incredibly thickly wooded and brushy, with all kinds of creeks and swamps making the area all that much more impenetrable. You can get lost in there in a heartbeat. That’s why it’s quite possible that nobody (who knows the difference)had seen an Ivory-Billed Woodpecker in there before.
David Sibley has recently weighed in, and he thinks it’s a pileated on the video. I myself am skeptical that the ivory-bill is still with us – the evidence is so sketchy that it hardly seems like there can be a viable population there. But I think the word “myth” is misplaced here. It’s not unnatural that there should have been hope and excitement over the reports. It would certainly be a huge good-news story if the sightings were confirmed.
What is the minimum population of a species? Is it conceivable that some speices sorvive in very small numbers? Like the California Monterey cypress tree-it only suvives today in a very small range. Likewise the Tasmanian marsupial wolf-they haven’t seen one since 1938-but there are reports of sightings. Could there be perhaps a few hundered birds and that is all?
Aren’t some species of birds (I’m thinking of parrots) extremely long lived? Is it possible that as few as ONE ivory bill has survived all these years?
ralph124c, the usual numbers biologists use for species viability is 50/500 - 50 individuals for immediate survival, 500 to maintain enough genetic diversity to survive in the long-term. This is, obviously, variable depending on a lot of factors of the species it’s being applied to, and I don’t think anyone’s come up with a more sophisticated equation.
It’s for that exact reason that I tend to doubt species still exist in fairly well-explored plances when they haven’t been seen in a while. There needs to be (rule of thumb) 50 to keep a population going, and 50 is hard to miss in Louisiana, I’d say. Of course, when you’re talking about the Amazon or Indonesia, it’s very easy to miss those kind of numbers.
I agree that the wing pattern in the video does make it look very much like an Ivory-billed. But unfortunately the picture quality is extremely poor, so it could either be a Pileated with abnormal white markings on the wings (which have been seen in the area) or just the appearance of larger white patches for some reason.
Sibley’s an artist. Who cares what he thinks? From what I hear, he’s not a terribly great birder, anyway.
And the amount of white on the wing is more or less irrelevant. Look at the video. There is white on the trailing side of the wing. The PIWO has white only on the leading edge of the wing.
Oh, I’m not stating it as fact, as you can see. It’s just what I’ve heard.
Anyway, their analysis is absurd. The only evidence I’m using to call it an IBWO is the video I linked to, pointing out the fact that the white is on the trailing edge, and not on the leading edge.
They attempt to refute this with a still photograph (albeit a particularly bad one) of a Mallard. Do they not have video to actually show this “wing twisting” illusion in action? I do not disagree that birds twist their wings in flight. But that is not what is happening here, and David and gang have not provided evidence that this could be the case.
Fig. 2 (F) is irrelevant. That bird is taking flight. Wing positioning during take-off is different from that of an in-flight bird.
They claim that Fig. 3 (A) shows a black trailing edge to the wing. This is a stretch. Sure, if you interpret and resketch the still image the way ol’ David did, it can be seen as a black trailing edge. But look at the video. Watch it again. And again. Where’d the black trailing edge go?
It is also quite silly that they dismiss the white on the bird’s back as a video artifact, but maintain that the black streak you see is a black trailing edge. They are choosing which evidence to accept in order to support their opinion.
But shit, everyone knew that the first people to challenge the evidence would get published in Science, so who wouldn’t give it a decent go?
I’m not even saying that this is definitely an IBWO. But, the evidence points to it being so, and the challenges are weak at best.
Anyway, I have a paper to finish, so I couldn’t look at all of their points. Maybe when I’m done.
Now, instead of merely citing irrelevant interpretive sketches and a a photo of a duck, have a look at these videos of PIWO in flight. Look, in particular, at the last video on the page. It is similar in angle and quality to the disputed IBWO video. See that? See the black trailing edge of the wing? Yes, you do. Do you see the silly twisting illusion that David and friends claim explains the IBWO video? No, you don’t. Nor could you, or they, find video of a PIWO in flight that recreates this “illusion.” Go ahead. Look. They did, that’s for sure.
Of course, this evidence does not prove that it is an IBWO. But it illustrates that the Sibley critique is beyond weak.
Continue on to the subsequent pages for further discussion of this silly challenge.
Again, it was clearly a grab at a Science publication. Science was more than expected to publish such a rebuttal, and this was likely the most coherent they received.
Cloaca, you may be right, you may be wrong. The documentary evidence for the ivory-bill’s existence is certainly no slam dunk, if different experts examine it frame by frame and come to different conclusions. It’s also a fact that some years of diligent searching have yielded almost nothing beyond a few seconds of footage of one possible individual, let alone any evidence of a viable population.
It’s also apparent to me that Cornell has an agenda here: the preservation of the Big Woods. I fully support the agenda, but I have to recognize that Cornell has a vested interest in maintaining that the ivory-bill exists.
