...Then, LOOK –- LOOK! Flying across the levy right in front was a large woodpecker. The sun was at our back so this could be the right time and the right place –- a large flash of white moved the blood-pressure up a notch –- then the bird morphed into the very common pileated. The shiny black feathers had reflected in the sun, and just for moment, there appeared to be white on the trailing edge of the wings. A slight change in the viewing angle and it was clear the white was not what it had seemed.Remember, in the spring of '04, searchers had the idea that Ivory-bills had been confirmed in the area. Ron Rohrbaugh said:
It was an absolutely electric time. To think that around every bend, behind every big cypress, there could be an ivory-bill.To review: In the spring of '04, you had searchers that really wanted to see an Ivory-bill; furthermore, they believed Ivory-bills had already been confirmed in the immediate area; and they were willing to place great emphasis on just one fieldmark (a glimpse of apparent trailing white wing edges).
When you then add in the presence of abnormal Pileateds in the area, you've got a perfect recipe for many incorrect "Ivory-bill" sight records.
Posts
20 comments:
I think you're forgetting that that kind of mistake could only happen with brief glimpses. Oh, ah... never mind.
I have been following your postings here for a while, and I fear that you are gradually shifting from simple criticism and skepticism to an ongoing harangue. You seem to repond to everything by simply repeating the same points you made months ago; but more worrying is that you seem to be increasingly insinuating that there is an actual cover-up in progress, not just normal scientific disagreement and uncertainty. I have reviewed all the evidence that has been publically posted myself, and while I do feel it is stronger than you do, virtually everyone agrees that it could be much stronger and is short of 100.0000000000% conclusive. The tone you have taken of a prosecuting attorney in a high-profile murder case is feeling more and more inappropriate.
I recently visited the Big Woods (briefly), and can attest that the habitat is remarkable and more woodpecker friendly than anywhere else I have ever seen. We saw some of the suspected ivorybill scalings, and the are unlike anything I have seen in my extensive experience in other southern swamps. This is of course hardly evidence at all, but at least I have actually BEEN there. I can also verify that these areas are not at all "remote, isolated, and difficult to work in;" they are 1 hour by interstate from two major metro areas, and the public lands are criss-crossed with well-maintained roads, trails, and boat ramps. The woods themselves, being so mature and filled with so many wonderfull huge trees, have quite open understories which makes travel rather easy at low water. Why they have been billed as impenetrable jungles I am not sure, but I suspect it was mostly to keep the crowds at bay. This is not necessary. The area is not even remotely overrun with birders, and considering its heavy use by hunters, throwing a few dozen birders a day in the mix would hardly even be noticeable.
One point I made to you by e-mail earleir that you did NOT rspond to is this: while swamps like these are frequented by hunters and fisherman, they are hardly ever visited by birders. I've been a southern birder most of my life, I speak from experience here. No one will put up with the ticks and chiggers and poison ivy just to see redbellies and chickadees. Birders in this area would have been driving around the cornfields marvelling at the throngs of snow geese and looking for a ross' goose; not bushwhacking in the swamps looking for bigfoot. A small population of ivorybills surviving in this location nearly undetected for decades is not at all unreasonable, becsuse the number of people actually LOOKING has been vanishingly small. And as for the hunters and fisherman, if you ask the oldtimers anywhere in the south about it, they will all tell you they have seen ivorybills. This has made it pretty much impossible to evaluate whether any of these reports are reasonable. A fisherwoman friend of mine says she saw a big black woodpecker with a white back and black crest in about 1979 in the upper Altamaha watershed in Georgia in an area where a recent inundation had created an extensive stand of dead and dying trees. Believable? I think it is worth considering. Confirmable? Absolutely not.
About wariness... a species that is somewhat secretive will seem much more secretive when the population densities are very low. For instance, wintering lincoln's sparrow occur at very low density in the southeast, and they are extremely difficult to find lurking invisibly in the bushes. But wintering lincoln's sparrows in the southwest are abundant, and you see them under feeders, in yards, all over. Are they more shy in the southeast? No, more likely it is just that they are SO numerous in the southwest that you will find them often, in spite of their shyness.
We ALL agree that we want better evidence. Endlessly repeating the same charges against the existing evidence and insinuating dishonesty and conspiracy in the people who actually went out into the swamps to collect this evidence is accomplishing nothing at this point. Your points have been made and heard already by all who will listen.
Current year search results will be available in a few months. THEN we will have something new to talk about.
Bill Pulliam
Hohenwald TN
eee-male (deliberately obfuscated to hide from spam bots): bee bee five five one at hot mail period com
Sorry to follow up on my own comment...
back of the envelope calculation:
let's assume that an ivorybill has a detection distance of 50m, meaning that the majority of birds within this distance will be detected, the majority of those beyond this distance will be missed. Lets also assume that an observer moving quietly at a birding-pace in ivorybill habitat will effectively traverse 1 km/hr, and that no birds detect and flee the observer before the observeer detects them. So, this observer is detecting the birds in 0.1 km2 per hour. These assumptions (other than the 1 km.hr speed) are actually quite generous in favor of detecting the bird.
The big woods area is about 200 km2. If this area contained a single ivorybill the detection rate would be about 1 bird/2000 observer hours. In other words, a single observer spending virtually all his time every day in this habitat moving quietly and on the lookout, would detect this single bird about once a year.
But.. "detection" does not mean "clearly seen and photographed." In woodland habitat, most birds are "briefly glimpsed: if seen at all. It's just that for the common ones, a brief glimpse is satisfactory. In Minnesota a big black-and-white woodpecker briefly glimpsed heading off through the woods is comfortably counted as a pileated. Let's be generous and assume that maybe 10% of detections will include "good views" of a perched bird. So this means that this single observer would need a decade of doing nothing but searching for ivorybills in the big woods before he would get a "good view." And lets not even bother with the next step, getting a good photograph.
Another way to figure this, is that if there is ALWAYS one observer (needen't be the same one) in the big woods searching, day in and day out, all year, a single ivorybill would be glimpsed about once a year, and seen well about once a decade. In fact, once observers started looking in this habitat in 2003, the rate of glimpses has been higher than this. Before 2003 I'd bet you that there was hardly ever ANYONE out there looking for this bird, much less at least one person all day every day. So, the rate of glimpses in fact might suggest the possibility of a population of more than one bird in the area. And the scarcity of photographs is to be expected. Face it, birds in woods are HARD to get clear pictures of!
Now that there is a crew of a couple of dozen people per day in the area, the chances of "good views" and a clear photograph increase. Still, though, the expected number of "good views" over the entire season is not more than a few, and the odds of a clear photograph are not anywhere near 100% EVEN IF THERE ARE MULTIPLE IVORYBILLS IN THE AREA. If the searchers are totally skunked, this is significant. If they return with glimpses, one clear view by someone who was unfortunatly alone at the time, and a blurry long-range photograph, that is not surprising.
PATIENCE, people! Science takes TIME!
Note -- a visual detection distance of 50m is quite generous for a woodland bird; small woodland passerines typically have visual detection distances much less than this (10m or so). And since it is clear that audio evidence will never prove completely satisfactory for this bird (the blue jay issue will never go away), visual detection is essential.
Bill Pulliam again
I think that Cornell honestly believes they have seen Ivory-billed woodpeckers. I also think they have attempted what is, in effect, a cover-up. As has been pointed out repeatedly, and with good reason, Cornell still has not told the whole story of the aberrant Pileated Woodpeckers they've admitted were there, nor have they produced the photos. Their cloak of secrecy over the search does nothing to boost my confidence.
Why they have been billed as impenetrable jungles I am not sure...
I think the answer to that is obvious: They believe in the bird, and they are looking for explanations of why they have no solid proof. So they say things like the woods are "nearly impenetrable", which they know to be untrue. Some people believe it though, and it's been repeated by believers over and over. But, as Carl Sagan would say, it's "baloney."
You are making a big error in assuming that "hunters are not birders." The fact is that tens of thousands of hunters in the U.S. are birders, and that, especially now, nearly all those hunter/birders would recognize an Ivory-bill if they saw one. That group includes me. While Cornell was pitching their "impenetrable jungle" line and "the search was top-secret" speech, I heard a recording of hunters in the swamp checking out an ARU and they were discussing that it must be one of those devices trying to record Ivory-billed woodpeckers. That recording was made BEFORE the "Big Announcement." Hunters aren’t smarter or more stupid than the average American, but they ARE far more aware of wildlife and birds than the average person.
I completely agree that a bird will SEEM more secretive if its population is low. But that is different than actually BEING more wary, isn't it? But Cornell has been telling us they ARE more wary.
A small population of ivorybills surviving in this location nearly undetected for decades is not at all unreasonable, becsuse the number of people actually LOOKING has been vanishingly small.
I think that statement is very misleading. The number of people who are out looking for albino deer in a given year is very, very small, yet the number of confirmed sightings of albino deer in a given year is quite high.
And now, "Ivory-bill awareness" is very high. The "you'll be laughed at" excuse if you report a sighting is no longer valid. There are tens of thousands of people who are aware and watching, if not actively looking.
Also, there HAVE been experts attempting to follow-up on the most credible sightings through the years, with Dr. Jackson being the perhaps the best example.
One thing I am pretty sure of: We'll hear about plenty of glimpses, but we won't see any good photos. Science takes time, but 60 years should be about long enough. Don’t give up, but be realistic.
I agree, there has been some repetition in this blog. But if that's a valid point, how about Cornell repeating the same old weak evidence over and over? Doesn't the same point apply? If the skeptics fall silent, the "proof" will be accepted as fact. But I disagree that this blog has failed to produce any new points. Just yesterday there was a post on how the Cornell searchers reported how the light produced an apparent white trailing edge in a Pileated Woodpecker. Since that's the only field mark Cornell saw, it’s a new important point, don't you think?
And one more point, I believe Tom has said that he HAS birded in Arkansas, although the relevance of that is questionable one way or another.
Cornell is not, however, accusing the skeptics of conspiracy, as far as I know. There are valid points in the criticism, and you may note that I never said whether or not I am a "believer." I did say I consider the evidence stronger than Tom does. I am in fact a scientist with my own probability meter shifting back and forth based on my own assessment of the evidence. It never dropped to 0% (though it was very low in 2002 after Pearl River), nor has it ever reached 100% (though it was very close to that immediately followign the Big Woods announcement in 2005). It dropped significantly when I first read Tom's critiques; but after examining the reports, recordings, and videos again myself it has risen again to above 50%. And my visit to the Big Woods helped bolster that assessment by convincing me that the habitat there is not so marginal as some have claimed.
I do believe the self-identified skeptics are stretching their criticisms at least as much as Cornell might be stretching its evidence, and that this is an increasing trend. It is beginning to take on the flavor of a Conspiracy Theory, which will do more to dampen serious debate than anything else.
Your point about hunters being birders feeds directly to my observation about the large number of them who in fact do believe they have seen an Ivorybill. But ALMOST EVERYONE has discounted these observations as unreliable in the large majority of cases.
I'd refer you to my back-of-the-envelope calculation about probabilities. There were a few people following up on sightings over 60 years. A very few of them, in their spare time, between their professional duties. Probably an average of less than a dozen observer-days per YEAR during this time, spread out over a seven State area. And there have not been "zero" sightings in that time; there have been zero CONFIRMED sightings. There have been several quite possibly valid but unconfirmed sightings, roughly one per decade. That does not seem unreasonable to me for a very small relict population of a bird that lives in one of the most underbirded habitats in North America. Recall that there are species known to have passed through bottlenecks of very very few individuals. Whooping cranes were down to 11, I believe. Genetic evidence suggests that at some point in recent prehistory Cheetahs might have been down to a population of as small as 2 individuals, a bottleneck from which they recovered without human intervention.
My point here is that the scant evidence of survival to date, even before the Big Woods sightings, is not inconsistent with a very small surviving and reproducing population within the lower Mississippi corridor. One cannot rule out this scenario as being possible, or even reasonable, simply on the basis of there having been very few sightings and no proven ones during this time. And of course, the scenario that the species is extinct and the few seemingly credible sightings are the results of rare combinations of circumstances that lead to a reliable observer being mistaken, is also consistent with this evidence. Ocam's razor is not in fact clear on which of these is the simplest explanation; both require some unlikely events. In the case of a low-density woodland species, both extinction and survival can be difficult to "prove." Some believe the evidence for survival remains weak and inconclusive; but the evidence for extinction can also be shown to be weaker and less conclusive than many believe.
Bill Pulliam
Further clarification about white trailing edges and personal probability meters...
It is misleading to say that all the visual evidence hinges on the white trailing wing and nothing else was seen. True this is the one consistent mark noted by all observers, and the only one that appears clearly in the Luneau video [I do not agree with Tom's assesment that this video is somehow showing the underside of the wing on upstroka and downstroke; his Pileated video has entirely different geometry]. However, one of the sightings clearly noted the loon-like flight of the bird in sharp contrast to pileated flight. I believe this flight style is also visible in the Luneau video, but I realize this is not a universally held opinion. Two of the sightings also noted that the crest of the flying bird appeared entirely black or mostly black with only a small crescent of red at the rear. One of the sightings noted a long bill, though I agree entirely it would be really nice if anyone had ever noted a long PALE bill, which no one did. The totality of visual and video evidence is not undermined by either of the two suggested alternatives: optical illusion or abberant pileated. The pileated would have to be simultaneously abberant in plumage AND behavior.
Though inconclusive on their own, I am also swayed by the audio evidence and the scalings, especially now that I have seen the scaling in person. Honestly my reaction to the scaling was "What on earth did THIS? That is really strange!" before I realized that it might be the unusual scaling I had heard about. It was something that jumped out at me, not something I had to look hard for.
I don't think I would need a photograph to push my personal meter to 100%. I think i would be satisfied with a clear view of a perched bird by a reliable observer, who noted all the plumage details of the head and neck, as well as the dang PALE BILL that no one has reported so far. And to push it down to 0% I would need better alternative explanations for each of the bits of evidence: e.g. definite evidence that pileateds (or woodrats or alligators or whatever)make the scaling and some other identified source for the double knocks, and sightings of definite pileateds flying like loons when pursued by crows. Until such time, I remain in a probabilistic limbo; me and Schroedinger's cat.
Bill Pulliam
Debate is good.
Do you believe Cornell has told the full story on the aberrant Pileated Woodpeckers in the area?
If not, don't you think they are covering up contradictory evidence? And if so, wouldn't that be a "cover-up" and flawed science?
Well considering two team members have discussed it publically, and both are absolutely convinced that these abberant birds are not responsible for the Ivorybill sightings, I do not see any evidence of a cover-up. Has anyone flat out asked them (in writing, directly and non-confontationally) if pictures of these birds exist and if they could see some of them? Considering that the two mentions cited here are from (a) the popular press and (b) a Q&A session at a meeting, it is entirely possible that the pictures don't actually exist and the speaker simply mispoke about there existence.
As for the secrecy of the search, that was entirely understandable last year. This year I'm not actually seeing much secrecy. They held a press day earlier this month, and there have been articles on the findings (and lack of findings) so far. And except for the Benson Slough special research area, and the normal seasonal closures on the White River NWR South Unit, all the land remains quite open and accessible to the public -- including lands where sightings occured and possible double knocks and calls were recorded.
Didn't Mary Scott note the characteristic Ivorybill face pattern in her 2003 sighting (the only perched sighting) on the White River South Unit? I'll have to check what she posted.
Cornell clearly tried to avoid admitting there were aberrant Pileated woodpeckers in the area.
They made the big announcement last April, correct? In an August 21st entry on this blog this question was suggested for the AOU meeting: Were any partially-leucistic Pileateds seen in the Cache River area? If so, where was their abnormal coloration?
http://tomnelson.blogspot.com/2005/08/ibwo-questions-for-aou-meeting.html
The reason this question was suggested is that Cornell had never publicly admitted there were aberrant Pileateds in the area. As far as I know they STILL haven't admitted it except when directly asked in a public meeting.
Skeptics were laughed at for even suggesting the possibility of aberrant/leucistic Pileated Woodpeckers in the area before Cornell was finally FORCED to admit it.
Cornell went so far as to say in The Paper that their birds were NOT aberrant/leucistic Pileateds, but never mentioned some were spotted in the area. Bad science? No doubt about it.
How can this possibly be interpreted in any other way than Cornell was trying to cover up that damaging bit of information? And to suggest they might have been mistaken in admitting there was at least one photo of those aberrant Pileateds? Sorry, doesn't wash.
As far as no evidence of secrecy in this year’s search?? Birchick’s blog had this to say: The first rule about the Cornell Ivory-billed Woodpecker Search is you do not talk about the Ivory-billed Woodpecker Search. The second rule about the Cornell Ivory-billed Woodpecker Search is you do not talk about the Ivory-billed Woodpecker Search...
That’s secrecy.
Anonymous wrote:
"As far as no evidence of secrecy in this year’s search?? Birchick’s blog had this to say: The first rule about the Cornell Ivory-billed Woodpecker Search is you do not talk about the Ivory-billed Woodpecker Search. The second rule about the Cornell Ivory-billed Woodpecker Search is you do not talk about the Ivory-billed Woodpecker Search...
That’s secrecy."
Hey, did you ever see "Fight Club"? Yeah, I'm sure there's secrecy, but what Birdchick wrote was a joke.
This blog is very good at taking quotes out of context or just flat out not getting it. Like Ken Rosenberg saying he hoped there wouldn't be time for questions.
It may be a joke, but it's true.
Here's what Laura Erickson wrote in her blog (I put the bold in, the capitalization is hers):
But I would have to sign an agreement that all of my photos, videos, sound recordings, and field notes would BELONG 100% to Cornell University. They would have to give me special permission for each and every photo and word I put on my blog--even just to highlight the beauty and diversity of the habitat!
Like I said, secrecy.
I find it in general both helpful and polite if anonymous blog posters would sign their posts. I have no idea who I am talking with here, or how many different people.
The "Don't talk about the project" thing I saw and took as the intended joke. OF COURSE the individual volunteers should not reveal information about a high-profile scientific study without permission of the principle investigators. That is not their provence. This is perfectly ordinary procedure in pretty much all scientific research that could possibly be of interest to the mainstream press. The PIs don't want someone blabbing about a sighting that turns out to have been a false alarm, or inadvertently revealing the location of a promising roost hole that is near a public road, thereby resulting in disturbance of the site. This isn't secrecy, it's quality control and protection of the habitat. This is exactly the Conspiracy Theory mood I see growing, and it is dragging this discussion away from healthy debate.
So let's take it as given that an abberant pileated that could exactly mimic the black-white wing pattern of an Ivorybill exists in this area. Does this account for ALL the evidence reported by the observers? If you have not read the first-hand accounts of the observers, you should do so. My answer to that would be a strong "no." Multiple observers also noted marked difference between the flight style, size, and "jizz" of the birds they saw and those of pileated woodpeckers. These differences were all consistent with the bird seen being an actual ivorybill, not an abberant pileated. Tom proposes that these perceptions (which of course cannot be analysed riigorously as they are just that, peceptions of visual observers) were all the result of group-think, elevated expectations, and wishful thinking. I disagree that this can account for all the sightings. Many others feel similarly, either way. And that is where it will likely stay until there is more evidence, positive or negative.
I should add that differences in flight style and "jizz" of species that are otherwise nearly identical are commonly used to document observations of rare birds, especially pelagic species. Rare Bird Committees frequently accept this as good evidence if the observer is experienced and familiar with the common species to which the rarity is being compared. The differences in flight and "jizz" between ivorybills and pileateds seems to be much more pronounced than that between, say, two species of Pterodroma petrels.
Bill Pulliam
Sigh... how am I to carry on a debate with peope who don't even identify themselves?
If you work on ANY University research project about ANYTHING ANYWHERE you agree that your notes and data are property of the University. This is Standard Operating Procedure. There is nothing unusual about this. Nor are you supposed do disclose research results without permission of the PIs; it is their data that you are collecting for them. This is just plan and simply the way University research is conducted, just about all of it, just about everywhere, just about all the time. This is an empty argument. Drawing nefarious conclusions from this is absolutely unjustifiable.
oops forgot to sign the last comment...
Bill Pulliam
Let's get to the nitty gritty:
Is it Standard Operating Procedure in a scientific paper to present all the main relevant data? Yes or no.
Would it be relevant in weighing the evidence to know that there were aberrant Pileated Woodpeckers in the area? Yes or no.
According to standard scientific practice, should Cornell reveal how many of these birds they saw, exactly how these birds are plumaged, and allow others to see the photos? Again, yes or no.
Can you venture to guess why it wasn't included in the paper?
If you've publicly posted skepticism on the internet, you'd realize why some of us are unenthusiastic about posting our names.
And by the way, I'm personally aware of no skeptics who are saying they are certain the bird is extinct. You've asked for patience in the wait for conclusive proof. I think many people, including Cornell, may be wishing they had waited for more conclusive proof before releasing their Paper.
No one ever includes all their data in a paper in "Science". "Science" does not publish exhaustive monographs. It publishes highly condensed communications of immediate and wide interest. And no one in the scientific community ever thinks that just because something wa published in "Science: hat it is complete, exhaustive, or beyonf reproach.
You sem to be implying without actually saying it out loud that you think Cornell is perpetuating deliberate and conscious fraud. If this is what you mean, say it. Do not just insinuate it.
Kenn Kaufmann has expressed skepticism without his reputation suffering. Perhaps it is the style in which the skepticism is expressed that is the problem, not the ideas themselves. Anonymity is often used to avoid accountability or the need for civility.
No claim was made in the article that there were no abberant pileated woodpeckers or that there was no possibility of such a creature existing. The authors expressed confidence that these sightings were not of an abberant pileated woodpecker, and provided the evidence they felt supported this conclusion. If their evidence does not rule out an abberant pileated, that weakens their conclusion regardless of whether or not such a bird has actually been seen in the area. You do not need to cite the existence of such a bird in the area, you only need to show that the visual and video evidence, ALL of it, not just a field mark here or a field mark there, is consistent with an unusually-plumaged pileated. So do this. As I stated above, I do not think this can be done convincingly. The arguments I have seen thus far making this claim are incomplete and unconvincing. One might conclude that the presence of abberant birds is being invoked for emotional reasons to cast doubt and suspicion, not because it has any bearing on whether the reported visual and video evidence rules out such a bird.
Let's forget the white trailing edge, Show that EVERYTHING else reported in the sightings is also consistent with a pileated woodpecker.
Bill Pulliam
So how come nobody took up that challenge to show that everything about the sightings can be explained away as abnormal pileated? Maybe because... the sightings can't be explained away that way whether or not there are abnormal pileateds in the area, and all this howling about suppressed evidence is just a red herring to distract people from noticing that the skeptics arguments don't hold water? Naw, couldn't be that
Every part of the claims can be "explained away" by a combination of brief glimpses and human error, even without aberrant Pileateds needing to be involved. I personally don't think it's necessary for ANY of us to go through every last point for the umpteeth time.
you only need to show that the visual and video evidence, ALL of it, not just a field mark here or a field mark there, is consistent with an unusually-plumaged pileated.
In my opinion, that isn't a sensible statement. In any big study involving lots of evidence, you'll find evidence on both sides of the issue. We all acknowledge that, or at least we should. It certainly is the case in both sides of this issue.
Could someone please show me a picture of one of the pileateds, I'm a abnornal pileated skeptic.
Post a Comment