Before you go, I’d be interested to hear your response to Hauksen’s statistical point (post #71).
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new paper on the Ivory-billed Woodpecker (2 Viewers)
- Thread starter fishcrow
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Before you go, I’d be interested to hear your response to Hauksen’s statistical point (post #71).
Paul Longland
Well-known member
I am sure that the OP truly believes that what he has seen is IBW (and for all I know he may be correct) but as we all know, single observer sightings require extensive corroborative evidence in order to be accepted for record purposes. In this day and age that means images showing distinctive characteristics based on known empirical evidence and not assumptions. Simply stating that the wingbeats were too fast for species X is not evidence of species Y.
It is of course not impossible (see Jerdons Babbler) for previously thought extinct species to be rediscovered, however, if you stick your head above the parapet of peer review then you should be prepared to defend your stance with strong evidence and balanced debate rather than resorting to simply debunking anyone who does not agree with you.
If indeed this species is still extant, it is, ironically, most likely that some passer by will get a picture and post it on facebook or similar with a "what is this strange looking bird I came across? question. I suspect if that were to ever happen those having invested so much time into trying to "prove" their theories based on very circumstantial evidence would be the first to decry and try to disprove it rather than embracing the fact that they had been proven correct.
It is of course not impossible (see Jerdons Babbler) for previously thought extinct species to be rediscovered, however, if you stick your head above the parapet of peer review then you should be prepared to defend your stance with strong evidence and balanced debate rather than resorting to simply debunking anyone who does not agree with you.
If indeed this species is still extant, it is, ironically, most likely that some passer by will get a picture and post it on facebook or similar with a "what is this strange looking bird I came across? question. I suspect if that were to ever happen those having invested so much time into trying to "prove" their theories based on very circumstantial evidence would be the first to decry and try to disprove it rather than embracing the fact that they had been proven correct.
Shades of John Young and the Night Parrot perhaps?
I don't believe the poor guy ever got much benefit from his discovery either, just a lot of grief with the established powers.
In closing out my participation in this discussion, I need to address a claim that bird watchers are my peers. Nothing that anyone has posted here indicates that they are my peer. Not even remotely close. There is nothing wrong with that, but I can't allow uninformed claims about the Ivory-billed Woodpecker to go unchallenged.
I have observed many species of birds in many habitats all over the world. That aspect of my experience is only marginally relevant to the issues under consideration here, but I have a unique combination of experiences, knowledge, data, and skills that is relevant. Some of the critics have never set foot in a southern swamp forest. During eight years of fieldwork in such habitats, I had ten sightings of the Ivory-billed Woodpecker, heard its vocalizations, and obtained video footage during three of the encounters. The videos provide the only existing footage of several types of flight and other behaviors of the Ivory-billed Woodpecker. I spent years researching the history of this bird (including accounts of observations by Audubon, Tanner, and others) and related topics in ornithology, such as avian flight mechanics. I have 34 years of experience in a quantitative field of science, which was essential in analyzing the data. Despite a determined effort to prevent anything on this topic from being published, I managed to get all of my findings published.
The comments by David Sibley that were posted here have no relevance to the analysis of the 2008 video, which doesn't require any information on the flap rate of the Ivory-billed Woodpecker. The analysis is based on wing motion and the statistics of flap rate, which is used to rule out the Pileated Woodpecker (not to directly argue that the bird in the video is an Ivory-billed Woodpecker). An expert in woodpecker flight mechanics applied an approach that he had previously developed and applied to other woodpeckers and concluded that the bird in the video is a large woodpecker. The flap rate of the bird in the video is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker. According to an expert in applications of statistics, it is a slam-dunk that the bird in the 2008 video is not a Pileated Woodpecker. There is only one plausible conclusion that follows from these facts, which are inconvenient for critics who seem to be focused on winning an argument rather than seeking the truth.
In addition to the wing motion and flap rate, there is icing on the cake. The high flight speed, narrow wings, swept-back appearance of the wings, and prominent white patches on the dorsal surfaces of the wings are consistent with the Ivory-billed Woodpecker but not the Pileated Woodpecker. Although no information is required on the flap rate of the Ivory-billed Woodpecker, the high flap rate is consistent with Tanner's account of rapid wingbeats, Pennycuick's empirical model in which high body mass and narrow wings (both characteristics of the Ivory-billed Woodpecker relative to the Pileated Woodpecker) correlate with a high flap rate, and the fact that the closely-related (and even larger) Imperial Woodpecker has a high flap rate (see the comparisons in Movie S11 of this paper). There are two other videos that contain strong evidence that nobody has been able to refute. In a quantitative sense, the 2007 video contains the strongest evidence, but it takes more of an effort to understand it. Without making an attempt to study the evidence and its analysis, critics have proposed flawed arguments in attempts to find holes in the analysis. This is not the approach of a truth seeker or anyone that I would regard as a peer.
Many people do amazing things that make me feel humbled. I have no problem acknowledging that I am not their peer. For example, I am in awe of the works of avian artists, such as David Sibley, Julie Zickefoose, and Michael DiGiorgio. But I am also aware of the limitations of their abilities when it comes to this issue. Avian artists do have something to offer, and this is exemplified by the insightful comments that Zickefoose made on the 2006 video. I had only recently begun my work in the Pearl River, and I learned a great deal from her inputs.
I have observed many species of birds in many habitats all over the world. That aspect of my experience is only marginally relevant to the issues under consideration here, but I have a unique combination of experiences, knowledge, data, and skills that is relevant. Some of the critics have never set foot in a southern swamp forest. During eight years of fieldwork in such habitats, I had ten sightings of the Ivory-billed Woodpecker, heard its vocalizations, and obtained video footage during three of the encounters. The videos provide the only existing footage of several types of flight and other behaviors of the Ivory-billed Woodpecker. I spent years researching the history of this bird (including accounts of observations by Audubon, Tanner, and others) and related topics in ornithology, such as avian flight mechanics. I have 34 years of experience in a quantitative field of science, which was essential in analyzing the data. Despite a determined effort to prevent anything on this topic from being published, I managed to get all of my findings published.
The comments by David Sibley that were posted here have no relevance to the analysis of the 2008 video, which doesn't require any information on the flap rate of the Ivory-billed Woodpecker. The analysis is based on wing motion and the statistics of flap rate, which is used to rule out the Pileated Woodpecker (not to directly argue that the bird in the video is an Ivory-billed Woodpecker). An expert in woodpecker flight mechanics applied an approach that he had previously developed and applied to other woodpeckers and concluded that the bird in the video is a large woodpecker. The flap rate of the bird in the video is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker. According to an expert in applications of statistics, it is a slam-dunk that the bird in the 2008 video is not a Pileated Woodpecker. There is only one plausible conclusion that follows from these facts, which are inconvenient for critics who seem to be focused on winning an argument rather than seeking the truth.
In addition to the wing motion and flap rate, there is icing on the cake. The high flight speed, narrow wings, swept-back appearance of the wings, and prominent white patches on the dorsal surfaces of the wings are consistent with the Ivory-billed Woodpecker but not the Pileated Woodpecker. Although no information is required on the flap rate of the Ivory-billed Woodpecker, the high flap rate is consistent with Tanner's account of rapid wingbeats, Pennycuick's empirical model in which high body mass and narrow wings (both characteristics of the Ivory-billed Woodpecker relative to the Pileated Woodpecker) correlate with a high flap rate, and the fact that the closely-related (and even larger) Imperial Woodpecker has a high flap rate (see the comparisons in Movie S11 of this paper). There are two other videos that contain strong evidence that nobody has been able to refute. In a quantitative sense, the 2007 video contains the strongest evidence, but it takes more of an effort to understand it. Without making an attempt to study the evidence and its analysis, critics have proposed flawed arguments in attempts to find holes in the analysis. This is not the approach of a truth seeker or anyone that I would regard as a peer.
Many people do amazing things that make me feel humbled. I have no problem acknowledging that I am not their peer. For example, I am in awe of the works of avian artists, such as David Sibley, Julie Zickefoose, and Michael DiGiorgio. But I am also aware of the limitations of their abilities when it comes to this issue. Avian artists do have something to offer, and this is exemplified by the insightful comments that Zickefoose made on the 2006 video. I had only recently begun my work in the Pearl River, and I learned a great deal from her inputs.
Sangahyando
Well-known member
A truly modest claim. I love how you just know that no-one here has the same amount of experience in statistics or related fields, because clearly you've conducted extensive background checks.
Anyway, I got the impression that Hauksen knows something about statistics, so why don't you address his point, or is he not peer-ish enough either?
By the way, have you considered that birdwatching usually isn't a job description (well for some of us, it is), and that birdwatchers might come from all walks of life?
Also, I'd love to know what the statistical probability is for a large bird like the IBWO to remain virtually undetected for decades (no clear photo evidence, no DNA...), in a country with a large number of top tier birdwatchers and scientists and no shortage of cryptid enthusiasts.
We truly do have a failure to communicate.
No one here ever claimed that birders were your peers, that would be the ornithological field workers.
So to persuade them, you need to get published in 'The Auk' or some similar professional journal, which incidentally are also the venues where topics such as wing flap rate deviances are likely to be very critically examined.
Here on BF you address the broader universe of mostly lay people interested in birds and nature. These are not likely to be persuaded by circumstantial evidence, rather they demand tangible proof, either good photographs or dead bodies. Do remember that John Young's photographs of Night Parrots were dismissed as hoaxes because he had photoshopped a wing covert.
The Ivory Bill is surely harder to find than even the Night Parrot, so there will be even greater unwillingness to accept its survival, especially as the bird would need to have changed its foraging strategy with the destruction of the old growth bottom land forests which it relied upon. I've seen only a handful of photos of excavations possibly done by an Ivory Bill. A surviving population should produce them continually, so their absence means the birds have adapted to their new environment or they are no longer there.
Your studies suggest they are still around, that means they must have developed a different foraging strategy. What could that be and is there any evidence for that?
Actually, I dido
But I've no wish to upset the OP any further by labouring the point.
Cringeworthy though it's been at times, and made worse by repetition, only time will tell whether his confidence is hubris or not.
Farnboro John
Well-known member
I bet we can get him to compromise his departure.... :t:
John
John
DMW
Well-known member
Good luck...
As stated previously, I'm not going to participate in discussions with bird watchers who repeatedly demonstrate a lack of logical reasoning skills, make comments on data they haven't bothered to study, and think they know it all when in fact they aren't aware of basic facts. However, I will address the above quote, which was attributed to David Sibley. Independent of the 2008 video, which is the only footage that has ever been obtained of an Ivory-billed Woodpecker in cruising flight, a great deal is known about the flap rate of this species. Tanner stated that the Ivory-billed Woodpecker has rapid wingbeats, and there is a substantial literature on the flap rate of birds in cruising flight.
Pennycuick used a large data set involving a wide variety of species to develop an empirical model for flap rate [J. Exp. Biol. 199, 1613–1618 (1996)]. In the quote above, there is a claim that a heavier species should have a lower flap rate, but increased mass actually correlates with a higher flap rate in Pennycuick's model. Furthermore, a film of an Imperial Woodpecker in flight reveals that that even heavier species has a higher flap rate than the Pileated Woodpecker. The other parameters in Pennycuick's model are the wingspan and wing surface area. There is a relatively small difference between the wingspans of the two large woodpeckers, but the Ivory-billed Woodpecker has much narrower wings, which correlates with a high flap rate.
Taylor et al. [Nature 425, 707–711 (2003)] developed a flap rate model that is based on the physics of vortex shedding. It predicts that the flap rate is proportional to the flight speed, with a proportionality factor that depends on wingspan. Since there is only a small difference in the wingspans of the two large woodpeckers, the model predicts that the species that has the higher flight speed should also have the higher flap rate. The narrow wings of the Ivory-billed Woodpecker are consistent with a high flight speed, and it is known from historical accounts that this species makes long flights at high speeds.
Although the two large woodpeckers are superficially similar, they are actually very different in terms of their behaviors and body parameters. The Pileated Woodpecker is a territorial species with a relatively low mass and relatively broad wings. The Ivory-billed Woodpecker makes long flights to distant foraging sites and has a relatively high mass and relatively narrow wings. All of this information is consistent with the Ivory-billed Woodpecker having a higher flap rate, and the 2008 video is the icing on the cake. I spent eight years in the Pearl River swamp observing the wingbeats of the Pileated Woodpecker on a daily basis. I observed the rapid wingbeats of the Ivory-billed Woodpecker during several encounters. The difference is dramatic. A good comparison is the difference in the flap rates of another pair of superficially similar species, the Northern Mockingbird and the Loggerhead Shrike. These birds are sometimes mistaken for each other when perched, but it is easy to tell them apart almost immediately after they take flight.
As mentioned previously, avian artists have something to offer in this debate. In his book on the Ivory-billed Woodpecker, Jerome Jackson thanks Julie Zickefoose for her cover art and her long interest in this species. One of her other paintings of the Ivory-billed Woodpecker appears on the cover of the January 2006 issue of The Auk. The comments that Zickefoose made on the 2006 video are the most significant contribution that any avian artist has made to this issue.
Farnboro John
Well-known member
Hi Mike,
Your fallacy is trying to argue that flap rates derived for characteristic speeds of species apply to an arbitrary section of flight of one observed individual.
You might want to check Tobalske's article here:
https://jeb.biologists.org/content/210/18/3135
Any individual flying at a higher speed than its Vmp, the characteristic speed for minimum power required (which is species dependend, and amenable to statistical analysis) will have to generate more propulsive power.
Tobalske's earlier measurements of woodpecker flap rates most likely captured them at speeds in the region of Vmp, as is evident from his descriptions of the capturing process.
Quite obviously, these flap rates don't apply to situations with a much higher power requirement, for example the top speed indicated at the right-hand side of Tobalske's U-shaped power graph in the linked article.
If you appreciate logical reasoning as much as you claim, why don't you show it by applying it yourself for a change?
Regards,
Henning
Your fallacy is trying to argue that flap rates derived for characteristic speeds of species apply to an arbitrary section of flight of one observed individual.
You might want to check Tobalske's article here:
https://jeb.biologists.org/content/210/18/3135
Any individual flying at a higher speed than its Vmp, the characteristic speed for minimum power required (which is species dependend, and amenable to statistical analysis) will have to generate more propulsive power.
Tobalske's earlier measurements of woodpecker flap rates most likely captured them at speeds in the region of Vmp, as is evident from his descriptions of the capturing process.
Quite obviously, these flap rates don't apply to situations with a much higher power requirement, for example the top speed indicated at the right-hand side of Tobalske's U-shaped power graph in the linked article.
If you appreciate logical reasoning as much as you claim, why don't you show it by applying it yourself for a change?
Regards,
Henning
Foxy
Well-known member
Coming from an aviation background my two penn'th is that the chord profile of the wing could make a massive difference to the lift generated and therefore the flap rates as well as size, weight etc so if there is a deeper camber in the wing there is greater lift generated and a slower flap rate required. I wonder if Pennycuick's model has factored in Albatros and Petrel species, raptors etc.
Unless the model knows both the plan form measurements and the cross section of the chord it can make no calculations about the lift co-efficient of the wing and therefore no predictions about the flap rate.
And fishcrow please don't patronise us all with 'I'm not going to participate in discussions with bird watchers who repeatedly demonstrate a lack of logical reasoning skills, make comments on data they haven't bothered to study, and think they know it all when in fact they aren't aware of basic facts.' Birdwatchers come from many different backgrounds and knowledge sets and most have something to contribute. Examine the chord profile, calculate the relative lift co-efficient of the wing and we might start to take you and the wing-flapping theory a little more seriously
Unless the model knows both the plan form measurements and the cross section of the chord it can make no calculations about the lift co-efficient of the wing and therefore no predictions about the flap rate.
And fishcrow please don't patronise us all with 'I'm not going to participate in discussions with bird watchers who repeatedly demonstrate a lack of logical reasoning skills, make comments on data they haven't bothered to study, and think they know it all when in fact they aren't aware of basic facts.' Birdwatchers come from many different backgrounds and knowledge sets and most have something to contribute. Examine the chord profile, calculate the relative lift co-efficient of the wing and we might start to take you and the wing-flapping theory a little more seriously
MJB
Well-known member
I just get the feeling that there's a good paper to be written by you and Henning...:t:
MJB
Hi MJB,
I guess all the papers one might need for understanding that birds need to flap quicker if they want to go faster are probably already out there ;-)
Browsing in Lilienthal's "Bird Flight as the Foundation of Artificial Flight", published in 1889, I noticed he included a qualitative description of just the kind of U-shaped graph Tobalske provided in the article I quoted above
Regards,
Henning
I guess all the papers one might need for understanding that birds need to flap quicker if they want to go faster are probably already out there ;-)
Browsing in Lilienthal's "Bird Flight as the Foundation of Artificial Flight", published in 1889, I noticed he included a qualitative description of just the kind of U-shaped graph Tobalske provided in the article I quoted above
Regards,
Henning
Andy Adcock
Worst person on Birdforum
Told you....
John
Repeated arguments, compromised departure, Brexit anyone....?
In this thread and others during the past decade or so, many birders have displayed hubris and ignorance in discussions of the Ivory-billed Woodpecker. Making comments on evidence that they admittedly haven't even seen. Posting comments by David Sibley that don't have any relevance to the evidence but do indicate a lack of awareness of established facts about avian flight. Assuming to know more than ornithologists and other scientists who bring relevant expertise to the table and have carefully examined the data.
One such expert is Geoff Hill, a recipient of the Brewster Award, which is given to the author of "the most meritorious body of work on birds of the Western Hemisphere published during the 10 calendar years preceding a given AOU Annual Meeting." Hill has observed an Ivory-billed Woodpecker, conducted years of fieldwork in its habitat, and published the most informative book that exists on this bird. Hill recognized the significance of my data early on. When I met him in the fall of 2006, he told me that the video that I obtained earlier that year was the best that had been obtained up to that point. In the years that followed, Hill met with me several times to study all three of the videos.
With the recent publication of what will probably be my final paper on the Ivory-billed Woodpecker, the time was right to have another meeting with Hill. Last week, we went through all of the events in the videos, and he regards all three of the videos to be convincing. One of them was obtained at a site where he had recently observed an Ivory-billed Woodpecker. I didn't need Hill to tell me that the evidence is convincing, but it's good to know that at least one ornithologist is willing to set politics aside and engage in an objective discussion of data. That is, of course, what any scientist should do when relevant data are obtained, but many ornithologists are reluctant to get involved in this issue.
The August 17, 2007, issue of Science, has the following quote by John Fitzpatrick: "Nobody else had the balls to do it," regarding being the lead author on the first paper in several decades to publish reports of this bird. It's a sad situation when a scientist needs courage to publish findings and have honest discussions of data. Fitzpatrick and Hill have been courageous, but they're outnumbered by cowards, such as the reviewers discussed in my latest paper who made claims anonymously that they have never dared to make publicly.
One such expert is Geoff Hill, a recipient of the Brewster Award, which is given to the author of "the most meritorious body of work on birds of the Western Hemisphere published during the 10 calendar years preceding a given AOU Annual Meeting." Hill has observed an Ivory-billed Woodpecker, conducted years of fieldwork in its habitat, and published the most informative book that exists on this bird. Hill recognized the significance of my data early on. When I met him in the fall of 2006, he told me that the video that I obtained earlier that year was the best that had been obtained up to that point. In the years that followed, Hill met with me several times to study all three of the videos.
With the recent publication of what will probably be my final paper on the Ivory-billed Woodpecker, the time was right to have another meeting with Hill. Last week, we went through all of the events in the videos, and he regards all three of the videos to be convincing. One of them was obtained at a site where he had recently observed an Ivory-billed Woodpecker. I didn't need Hill to tell me that the evidence is convincing, but it's good to know that at least one ornithologist is willing to set politics aside and engage in an objective discussion of data. That is, of course, what any scientist should do when relevant data are obtained, but many ornithologists are reluctant to get involved in this issue.
The August 17, 2007, issue of Science, has the following quote by John Fitzpatrick: "Nobody else had the balls to do it," regarding being the lead author on the first paper in several decades to publish reports of this bird. It's a sad situation when a scientist needs courage to publish findings and have honest discussions of data. Fitzpatrick and Hill have been courageous, but they're outnumbered by cowards, such as the reviewers discussed in my latest paper who made claims anonymously that they have never dared to make publicly.
Hi Mike,
Since you mention courage ... maybe you could work up a bit of that youself and try to reply to this post?
https://www.birdforum.net/showpost.php?p=3890857&postcount=76
"Hubris" is the consequence of overconfidence, and mathematics are a great way to overcome that, and bring back the discussion to a rational foundation.
Regards,
Henning
Since you mention courage ... maybe you could work up a bit of that youself and try to reply to this post?
https://www.birdforum.net/showpost.php?p=3890857&postcount=76
"Hubris" is the consequence of overconfidence, and mathematics are a great way to overcome that, and bring back the discussion to a rational foundation.
Regards,
Henning
Unfortunately Colin Pennycuick passed away about a year ago and he could have gotten all the variables for Ivory bill and imperial and pileated and maybe some more Campephilus plugged into his likely still available available flight performance program.
He lived in the United kingdom, not sure if he updated his program. You plug in the variables of a species and it would give you give you wing beat frequency.
Somewhere I have a bibliography of all the best papers for examining this situation. Maybe there's some new papers; gave the bibliography to others and they liked it.
For Ivory bill there are at least 3 pertinent flight sequences. The Rhein films have three sequences of flight for imperial. Now all you need to add to the above is see if there's any video of another large Campephilus. Weights will be easy weights will be easy but to get wing surface will require some work and specimens will have folded wings. I guess you could use pictures and a planimeter.
And there you're on your way to getting averages for hz and a standard deviation and a plot line for Campephilus weights.
If you're working on something serious I could help. Take care
By the way I am going to look at your comments from the past I see what you're getting at or we're getting at.
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