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new paper on the Ivory-billed Woodpecker

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Old Sunday 1st September 2019, 13:56   #51
fishcrow
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It's not necessary to be an expert on woodpecker flight mechanics in order to confirm that the bird in the 2008 video is a large woodpecker. The two large woodpeckers are the only large birds that occur north of the Rio Grande that fold their wings closed in the middle of each upstroke during cruising flight. An example of a Pileated Woodpecker in flight appears in this video. One may go through every family of birds, such as heron, hawks, etc. to confirm that they all keep their wings open throughout the entire flap cycle. Among the smaller birds, the largest that folds its wings closed (or nearly closed) is the Belted Kingfisher, which has prominent dorsal field marks that appear in Fig. 3 of this paper. There is no trace of those field marks in the video, which does show prominent white patches on the dorsal surfaces of the wings that are consistent with the Ivory-billed Woodpecker.
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Old Sunday 1st September 2019, 14:09   #52
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Thanks for linking to all the videos of the putative IBWs. Which one clearly shows the correct white wing markings for the species?
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Old Sunday 1st September 2019, 14:26   #53
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Hi Mike,

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Originally Posted by fishcrow View Post
Tobalske didn't claim to cover the full range of the Pileated's flight range. His flap rate statistics are for cruising flight, which is the only type of flight that is known to be amenable to statistical analysis.
How do you arrive at the conclusion that the filmed bird was in cruising flight?

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His paper is available here. His statistics for the Pileated are based on data obtained from five locations and 121 total flap cycles.
It's 1 location, 11 flights, in table 7, which deals with flight speed.

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I have obtained my own data on the Pileated and consulted with an expert in the applications of statistics, who regards the sampling as adequate and my data to be consistent with Tobalske's.
Tobalske's data does not show the variation of flap rate over flight speed, and you're using it as reference to an observation of a bird flying at a very different flight speed than those observed by Tobalske.

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I totally agree that Tobalske missed an opportunity.
What I actually said was, "I can't imagine he would have missed the opportunity to point out that the Pileated Woodpecker could be ruled out based on the recorded flap rate."

To put it bluntly, I believe that if Tobalske had agreed with your application of his data, he'd have said so, and I take his silence on the critical point as disagreement.

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Old Sunday 1st September 2019, 14:46   #54
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For those who understand that questions can often be answered by analyzing data that isn't a pretty picture, I suggest that you study the videos, each of which contains stronger evidence for the persistence of the Ivory-billed Woodpecker than anything else that has been obtained during the past several decades. This data has been studied by several independent experts. The comments of two of them appear in my papers. The editor of the journal that published an analysis of all the videos in 2017 made a public statement that the paper had been reviewed and recommended for publication by ornithologists.
Mate, I'm expressing sympathy for you. My default position is that anyone who tells a good story in earnest gets my ear...I have no agenda about IBW either way...fair play to you, well done...I would 'study' your videos, if I could see a bird, any bird, in just one of them. After having two of the links I tried to follow knocked back because whatever format they are in is not supported by my laptop, I gave up. I understand your desire to prove your sightings to a wider audience - do YOU understand why others are having trouble getting past the DREADFUL pictures presented? It might help you to be less defensive and condescending to those expressing legitimate doubts.

Just this past week a rather poor photograph of a potential first for Britain - a Brown Booby - was published from Kent. An AI programme went on to identify it as such. Well done AI - a major victory for modern technology? It's just a shame that the same programme went on to identify a known Gannet as a Brown Booby also! That's just one reason why modern field birdwatchers may justifiably recommend caution in considering 'data' and 'analysis' and 'statistics' any more reliable than the traditional senses.

Best of luck in your endeavours; I do hope one day to see some full frame pictures of yours of IBW on the front pages of National Geographical. Why not follow the example of the Native Indian shaman who would 'see' their quarry in their minds prior to setting out to look for it and be grateful for its manifestation BEFORE it happens? And be ready NOT to gloat or say 'I told you so' to all your doubters, if and when you achieve that goal. Just shrug your shoulders, drop the mike, and walk away
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Old Sunday 1st September 2019, 15:30   #55
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By mentioning that paper, you have demonstrated that you have no idea what you are talking about. The bird in the 2008 video was in cruising flight, which is the only type of avian flight that is amenable to statistical analysis. That paper discusses Pileated Woodpeckers that were flushed into escape flights.
I don't believe it is me that doesn't know what they are talking about. A stopwatch and the ability to count are all that is necessary to establish a flap rate for any bird in any mode of flight. One can easily establish a flap rate from two flaps: indeed by timing the cycle of one wingbeat one could even establish it from that. What analysis happens after that depends on the quality and duration of any recording: one could look at the bird's acceleration phase, cruise, maximum speed, deceleration, ascending, descending in detail with decent video. One could even look at rate of change of flap rate, over and above the flap rate itself.

What I really don't understand is why you would try to deny such obvious truth. Unless of course you have a very shaky conclusion that utterly depends on only one particular interpretation of a rubbish dataset. That is not good science and does your cause, let alone case, no favours.

John
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Old Sunday 1st September 2019, 15:34   #56
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It's not necessary to be an expert on woodpecker flight mechanics in order to confirm that the bird in the 2008 video is a large woodpecker. The two large woodpeckers are the only large birds that occur north of the Rio Grande that fold their wings closed in the middle of each upstroke during cruising flight. An example of a Pileated Woodpecker in flight appears in this video. One may go through every family of birds, such as heron, hawks, etc. to confirm that they all keep their wings open throughout the entire flap cycle. Among the smaller birds, the largest that folds its wings closed (or nearly closed) is the Belted Kingfisher, which has prominent dorsal field marks that appear in Fig. 3 of this paper. There is no trace of those field marks in the video, which does show prominent white patches on the dorsal surfaces of the wings that are consistent with the Ivory-billed Woodpecker.
This youtube video shows a Blue Jay fully closing its wings during flight (e.g. at 25 seconds).
https://m.youtube.com/watch?v=p_ODzvdfHCg
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Old Sunday 1st September 2019, 15:39   #57
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It is unfortunate when open discourse in science is stifled by ignorance, politics, and fear. I thought this kind of thing came to an end with the persecution of Galileo in the Middle Ages. I don't blame Tobalske or anyone else for shying away from this topic, but it was courageous of him to allow me to include his results in my papers. Several others have courageously made contributions to my work, including Julie Zickefoose for allowing me to use her assessment of the 2006 video, Geoff Hill for letting me use a Pileated Woodpecker specimen in a size comparison, John Fitzpatrick for allowing me to use various materials from Cornell, and Michael DiGiorgio for producing illustrations for me. I am very grateful to all of them. DiGiorgio was harassed by someone at an ornithology conference for doing those illustrations, one of which has already paid off. Figure 2 of my latest paper shows the type of long vertical ascents that appear in the 2007 video and that I observed while obtaining that footage. As discussed in this lecture, Laura Chazarreta, who has studied and published on the closely-related Magellanic Woodpecker, mentioned that this species has very similar long vertical ascents.
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Old Sunday 1st September 2019, 15:42   #58
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This youtube video shows a Blue Jay fully closing its wings during flight (e.g. at 25 seconds).
https://m.youtube.com/watch?v=p_ODzvdfHCg
You missed an important detail.
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Old Sunday 1st September 2019, 16:02   #59
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You missed an important detail.
Not nearly as many as you are missing, though... such as even a shred of credible evidence.
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Old Sunday 1st September 2019, 16:11   #60
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Hi Mike,



How do you arrive at the conclusion that the filmed bird was in cruising flight?



It's 1 location, 11 flights, in table 7, which deals with flight speed.



Tobalske's data does not show the variation of flap rate over flight speed, and you're using it as reference to an observation of a bird flying at a very different flight speed than those observed by Tobalske.



What I actually said was, "I can't imagine he would have missed the opportunity to point out that the Pileated Woodpecker could be ruled out based on the recorded flap rate."

To put it bluntly, I believe that if Tobalske had agreed with your application of his data, he'd have said so, and I take his silence on the critical point as disagreement.

Regards,

Henning
Tobalske concluded that the bird in the video is a large woodpecker. It is a trivial matter to estimate the flap rate from the video, and the value is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker. Tobalske pointed this out with the comment, "The bird appears to have a wingbeat frequency of 10-12 Hz, which is approximately double that of the Pileated Woodpecker. So the wingbeat frequency would seem much too high (well outside three standard deviations) to be from a Pileated Woodpecker." It would be easy for anyone to step through the video one frame at a time, count the number of frames per flap cycle, estimate the flap rate, and then compare with Tobalske's results. You seem to be making an assumption that "his silence" was based on disagreement. On what point?

It is straightforward in the field to decide whether a bird is in cruising flight, taking off, escaping from danger, etc. This has been done in various studies of avian flap rate, including the ones by Pennycuick and Tobalske that are cited. To obtain the statistics of avian flap rate, the mean and standard deviation are constant values that are obtained by averaging over many events involving birds that may be flying over a range speeds that also have a statistical distribution (although this topic has apparently not been addressed in as much depth as flap rate, which is much easier to measure in the field). It is true that the flight speed of the bird in the 2008 video is very different from the range of flight speeds that Tobalske measured for the Pileated Woodpecker, but that has no bearing on the conclusion that this species may be ruled out on the basis of flap rate.
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Old Sunday 1st September 2019, 16:20   #61
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Not nearly as many as you are missing, though... such as even a shred of credible evidence.
Credibility is in the eye of the beholder. Signs that my data have credibility include the published assessments of independent experts, comments made privately by other ornithologists and scientists who have studied the data, comments by anonymous reviewers, and the fact that it has been published and analyzed in a series of papers.
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Old Sunday 1st September 2019, 16:29   #62
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After having two of the links I tried to follow knocked back because whatever format they are in is not supported by my laptop, I gave up. I understand your desire to prove your sightings to a wider audience - do YOU understand why others are having trouble getting past the DREADFUL pictures presented?
You state that you weren't able to view the data and gave up. If that is true, how can you make any informed comment about the data, one way or the other? Just for your information, the data that you refer to as "dreadful" received strong positive assessments from independent experts. If you are expected a pretty picture, nobody has managed to obtain one since the 1930s. If you are interested in the strongest evidence for the persistence of the Ivory-billed Woodpecker that has been obtained during the past several decades, you might consider the following comments by an anonymous reviewer:

"Flight characteristics are the key to the analysis, although other aspects of wing shape and markings are also pointed out. Looking at the putative video before seeing the analysis, one may wonder how any progress on deciding if the video is of the Ivory-billed woodpecker can be made, since it is fleeting footage from far away. I am impressed by the authorís being able to provide an analysis of flap rate and takeoff and landing characteristics that is very compelling."
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Old Sunday 1st September 2019, 16:32   #63
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Tobalske concluded that the bird in the video is a large woodpecker. It is a trivial matter to estimate the flap rate from the video, and the value is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker. Tobalske pointed this out with the comment, "The bird appears to have a wingbeat frequency of 10-12 Hz, which is approximately double that of the Pileated Woodpecker. So the wingbeat frequency would seem much too high (well outside three standard deviations) to be from a Pileated Woodpecker." It would be easy for anyone to step through the video one frame at a time, count the number of frames per flap cycle, estimate the flap rate, and then compare with Tobalske's results. You seem to be making an assumption that "his silence" was based on disagreement. On what point?

It is straightforward in the field to decide whether a bird is in cruising flight, taking off, escaping from danger, etc. This has been done in various studies of avian flap rate, including the ones by Pennycuick and Tobalske that are cited. To obtain the statistics of avian flap rate, the mean and standard deviation are constant values that are obtained by averaging over many events involving birds that may be flying over a range speeds that also have a statistical distribution (although this topic has apparently not been addressed in as much depth as flap rate, which is much easier to measure in the field). It is true that the flight speed of the bird in the 2008 video is very different from the range of flight speeds that Tobalske measured for the Pileated Woodpecker, but that has no bearing on the conclusion that this species may be ruled out on the basis of flap rate.
The trouble with all this misuse and abuse of statistics is that whatever the mean and standard deviations of cruise flapping of two woodpecker species (and I haven't yet seen any explanation of the supposed dataset for IBWO given the bird's existence is what is being investigated: the recent alleged data can't be used in circular justification of itself), all that is needed is the minimum and maximum for each species. If there is overlap of the two species' flap rates its game over.

I don't have a complete set either, but I already know that Pileated Woodpecker has been measured flapping at up to at least 8.6 Hz, so Tobalske's claims that 10-12 Hz is double Pileated Woodpecker's flap rate are invalid and no pratting about with dodgy statistical calculations will change that. All we know is that the minimum difference is 1.4 Hz and the maximum, 3.4 - and that is not from a measurement claimed to be Pileated Woodpecker's maximum flap rate, so there's no reason to believe Pileated can't flap faster. Indeed, as the slightly smaller bird one would expect it to be able to flap faster than the larger! One also has to wonder where on earth figures of 10-12 Hz for IBWO come from, unless its a ludicrous extrapolation from some old film.

John

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Old Sunday 1st September 2019, 16:55   #64
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Hi Mike,

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Tobalske concluded that the bird in the video is a large woodpecker. It is a trivial matter to estimate the flap rate from the video, and the value is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker.
It's just as elementary that the standard deviation is just an indication that the deviation from the mean is unlikely to be the results of mere random fluctuations.

The observed bird being of a different species would be one example for a systematic difference, the observed bird being a Pileated Woodpecker in a hurry is another.

Your paper doesn't even try to exclude the latter case.

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It is true that the flight speed of the bird in the 2008 video is very different from the range of flight speeds that Tobalske measured for the Pileated Woodpecker, but that has no bearing on the conclusion that this species may be ruled out on the basis of flap rate.
You're basically asserting that flap rate is independend of flight speed.

If you have evidence for that, it would really boost the strength of your argument if you'd provide it.

It's not in the referenced Tobalske article, as far as I can see.

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You seem to be making an assumption that "his silence" was based on disagreement. On what point?
Maybe it helps if I highlight the point:

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What I actually said was, "I can't imagine he would have missed the opportunity to point out that the Pileated Woodpecker could be ruled out based on the recorded flap rate."

To put it bluntly, I believe that if Tobalske had agreed with your application of his data, he'd have said so, and I take his silence on the critical point as disagreement.
Regards,

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Old Sunday 1st September 2019, 16:57   #65
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Would be nice to get this before you disappear off on your travels: Which video clearly shows the correct white wing markings for IBW?
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Old Sunday 1st September 2019, 17:15   #66
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Would be nice to get this before you disappear off on your travels: Which video clearly shows the correct white wing markings for IBW?
They are discussed starting at about 5:38 in this lecture on the 2008 video.
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Old Sunday 1st September 2019, 17:18   #67
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You state that you weren't able to view the data and gave up. If that is true, how can you make any informed comment about the data, one way or the other? Just for your information, the data that you refer to as "dreadful" received strong positive assessments from independent experts. "
I saw a number of photos of leaves and branches and some arrows pointing at something I couldn't see, as well as a couple of miscellaneous shapes that may or may not have been birds. I really hoped from the intro you gave it, that there would be something tangible there that would help maintain my interest in a subject I have only a very very small stake in. But there wasn't. I've rarely had my computer not be able to open a down-loaded video in twenty year's experience - it might be something you want to look at if you hope to draw a wider audience? The photographs, and the comments from people I know and trust, suggested I wouldn't be rewarded by trying to find the appropriate program to open them. That is why, in the spirit of helpfulness, I pointed out the shortcomings of the 'evidence' presented.

'Independent expert?' What's one of them when it's at home? Someone recently referred to my good self as a 'World Class Birder'. What does that even mean I'm sorry... there are plenty of 'independent experts' on here who'll tell you you're photos are dreadful. 'We' are your peers, as much as anyone. We've been there, done that, talked the talk and walked the walk. Again, despite your disingenuous and defensive reply to my attempt to reach out to you with compassion, I'l tell you the truth: I don't disbelieve your story at all. But I understand why others would.
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Old Sunday 1st September 2019, 17:37   #68
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It's just as elementary that the standard deviation is just an indication that the deviation from the mean is unlikely to be the results of mere random fluctuations.
The standard deviation is a measure of how observations fluctuate about the mean. In this case, the flap rate of the bird in the video is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker. That species may therefore be ruled out. I consulted with experts in applications of statistics about what may be concluded from ten standard deviations. They are in agreement that ten standard deviations is conclusive. According to David Banks of Duke University, for example, it is a statistical "slam dunk" that the bird in the video is not a Pileated Woodpecker.
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Old Sunday 1st September 2019, 17:43   #69
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The irony here is that all of us would love for fishcrow to be right. We all want there to be a population of IBWOs somewhere, and would be delighted to see anything that was remotely suggestive of the species, let alone conclusive. A few years ago, another long-lost species was sort of rediscovered on Bird Forum, when somebody posted some photos of a pigeon from Indonesia, and asked for comments. The photos were terrible, but there was just enough detail for a strong case for the bird being Silvery Pigeon to be made. This was subsequently demonstrated to be correct.

Sadly the current thread is basically the opposite. We are being told that half a dozen pixels are, through the magic of peer-reviewed science, conclusive proof and we are more or less idiots if we disagree.
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Old Sunday 1st September 2019, 18:00   #70
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They are discussed starting at about 5:38 in this lecture on the 2008 video.
Thanks again and well done for continuing the debate in the face of adversity.

Wings look dark in some frames and pale in others, which is not in the least bit unusual for a host of species, and I couldnít possibly discern more detail than that with footage of such desperately poor quality. For what itís worth, my money would be on a Belted K.

If I ever come face to face with an IBW, I will not be concentrating on eye colour. And I donít plan to send the British Birds Rarities Committee a cartoon of me not seeing a bird as evidence of the next rarity I find (if indeed there ever is another one!). I do appreciate the cartoons are only illustrative, they just seem really odd in a scientific paper - and they seem to do more harm than good.

I tend to agree with all the negative points made so far on here Iím afraid.

Really hope weíre all wrong and they are out there. Possibly at odds with others, it wouldnít even need a photo for me, just a convincing description that rang true and had all the hall marks of an experienced and authentic birder, preferably one with a decent reputation (and I know nothing of yours Iím afraid so I remain neutral there).
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Old Sunday 1st September 2019, 18:05   #71
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Hi Mike,

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The standard deviation is a measure of how observations fluctuate about the mean. In this case, the flap rate of the bird in the video is about ten standard deviations greater than the mean flap rate of the Pileated Woodpecker. That species may therefore be ruled out.
You can only draw probabilistic conclusions from the standard deviations, so even in the best of cases, you could not rule out the Pileated Woodpecker with certainty.

To draw a numeric conclusion from the size of the standard deviation, you must know, or be able to assume with a high degree of confidence, that the observed values follow the normal (Gaussian) distribution ... which can usually be safely assumed if the results vary stochastically due to the influence of a sufficiently high number of small random influences.

That assumption goes out of the window the moment a systematic influence, such as the bird reacting to the power requirement for high-speed flight, enters the picture.

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Old Sunday 1st September 2019, 18:30   #72
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I saw a number of photos of leaves and branches and some arrows pointing at something I couldn't see, as well as a couple of miscellaneous shapes that may or may not have been birds. I really hoped from the intro you gave it, that there would be something tangible there that would help maintain my interest in a subject I have only a very very small stake in. But there wasn't. I've rarely had my computer not be able to open a down-loaded video in twenty year's experience - it might be something you want to look at if you hope to draw a wider audience? The photographs, and the comments from people I know and trust, suggested I wouldn't be rewarded by trying to find the appropriate program to open them. That is why, in the spirit of helpfulness, I pointed out the shortcomings of the 'evidence' presented.

'Independent expert?' What's one of them when it's at home? Someone recently referred to my good self as a 'World Class Birder'. What does that even mean I'm sorry... there are plenty of 'independent experts' on here who'll tell you you're photos are dreadful. 'We' are your peers, as much as anyone. We've been there, done that, talked the talk and walked the walk. Again, despite your disingenuous and defensive reply to my attempt to reach out to you with compassion, I'l tell you the truth: I don't disbelieve your story at all. But I understand why others would.
I'm sorry that you aren't able to play the mp4 and mov files (which are industry standards) on your computer. Which specific videos gave you trouble? I have always used standard programs to encode videos. The ones that I have posted on YouTube have been viewed for a total of 254 days of watch time. It seems puzzling that you would comment on evidence that you haven't even seen. After carefully studying the data, ornithologists and other scientists have made very positive comments (including that the videos are convincing) about the evidence and recommended it for publication.

The independent experts whose comments on the videos appear in my papers include Bret Tobalske, who is widely regarded as THE expert on woodpecker flight mechanics, and Julie Zickefoose, an avian artist whose paintings of the Ivory-billed Woodpecker have appeared on the covers of major publications in ornithology. You seem to be dismissing her credentials, but avian artists study their subjects in great deal; Science gave another avian artist a platform for providing his inputs on this issue.

How you stand in the birding community isn't relevant. The issue here isn't to look at a pretty picture and decide if it matches a bird that appears in a field guide. The issue is to analyze the videos using logical arguments that are based on any available information, such as avian flight mechanics, the statistics of flap rate, concepts in probability, flight speed, wing and other body proportions, flap rate models, historical accounts of the Ivory-billed Woodpecker, comparisons with the Pileated Woodpecker and other Campephilus woodpeckers, etc.

I didn't regard my reply as disingenuous and defensive, but were you expecting me to be Mr. Nice Guy after you included a remark about Bigfoot?
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Old Sunday 1st September 2019, 18:38   #73
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Thanks again and well done for continuing the debate in the face of adversity.

Wings look dark in some frames and pale in others, which is not in the least bit unusual for a host of species, and I couldnít possibly discern more detail than that with footage of such desperately poor quality. For what itís worth, my money would be on a Belted K.

If I ever come face to face with an IBW, I will not be concentrating on eye colour. And I donít plan to send the British Birds Rarities Committee a cartoon of me not seeing a bird as evidence of the next rarity I find (if indeed there ever is another one!). I do appreciate the cartoons are only illustrative, they just seem really odd in a scientific paper - and they seem to do more harm than good.

I tend to agree with all the negative points made so far on here Iím afraid.

Really hope weíre all wrong and they are out there. Possibly at odds with others, it wouldnít even need a photo for me, just a convincing description that rang true and had all the hall marks of an experienced and authentic birder, preferably one with a decent reputation (and I know nothing of yours Iím afraid so I remain neutral there).
Everyone has their own opinion. Other scientists have told me that they love the illustrations. I would certainly enjoy seeing recreations of the scenarios of other observations of this species. The difference in the color of the eyes of the large woodpeckers and the surrounding plumage is a major difference between the large woodpeckers. I did observe this difference in the field, it was a very interesting observation, and it is relevant to report as many details as possible of an observation. The bird in the 2008 video flew near reference objects, and it was possible to pin down its location by triangulation since the bird and its reflection appear in the video. A reference object that was placed in the scene and a photo was obtained and compared with the video. The wingspan is substantially greater than the wingspan of the Belted Kingfisher, and there is no trace of the strong dorsal field marks on the wings of that species. My analysis of the video is based on logical arguments. You have expressed no logical reasons for betting on the Belted Kingfisher.
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Old Sunday 1st September 2019, 18:39   #74
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Originally Posted by Hauksen View Post
You can only draw probabilistic conclusions from the standard deviations, so even in the best of cases, you could not rule out the Pileated Woodpecker with certainty.
In this case, it is a statistical slam dunk that it's not a Pileated Woodpecker according to an expert in the application of statistics.
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Old Sunday 1st September 2019, 18:49   #75
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The difference in the color of the eyes of the large woodpeckers and the surrounding plumage is a major difference between the large woodpeckers. I did observe this difference in the field, it was a very interesting observation, and it is relevant to report as many details as possible of an observation.
You've seen it well enough to discern eye colour yet have no clear photograph or video despite years of effort? A species widely believed extinct that you are searching for evidence to disprove that hypothesis. That you go into the field equipped with camera traps, 'reference objects' and statistics to help you...yet you saw it well enough wi discern the eye colour...

Sorry dude, that boat ain't floating...

Not to mention the oh so shy Sanger Tract Birds sitting on researchers heads at the nest site...yet one human generation later they have evolved stealth-like cloaking traits to stop us obtaining clear photos or videos but do let you see the eye colour...

We did this to death on the other thread years ago...it's gone...let it go...
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