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new paper on the Ivory-billed Woodpecker (1 Viewer)
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rollingthunder
Well-known member
With a large, well searched for, species like IBW a recorded image is required and i would like to see some links to substantiate the claims. The papers linked are fine but without visual backup it’s just academic waffle imho and still ‘habeus corpus’.....
Laurie:t:
Laurie:t:
Hi Mike,
Thanks a lot for the link!
Tobalske's 1996 data set on the Pileated Woodpecker consisted of merely 11 observed flights on a single location, and as far as I can tell, he makes no claims to having covered the full range of the Pileated Woodpecker's flight capabilities with this set.
So all you can really conclude from that is that the bird in the video under discussion did not behave like the Pileated Woodpecker(s) observed by Tobalske.
Since Tobalske apparently assessed and commented on the video, 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.
Is the full text of his assessment accessible online?
Regards,
Henning
Thanks a lot for the link!
Tobalske's 1996 data set on the Pileated Woodpecker consisted of merely 11 observed flights on a single location, and as far as I can tell, he makes no claims to having covered the full range of the Pileated Woodpecker's flight capabilities with this set.
So all you can really conclude from that is that the bird in the video under discussion did not behave like the Pileated Woodpecker(s) observed by Tobalske.
Since Tobalske apparently assessed and commented on the video, 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.
Is the full text of his assessment accessible online?
Regards,
Henning
This seems to show ‘the best of the sequences available’. The article also comments ‘most of the excerpts show distant blurs that only vaguely resemble birds’:
https://www.audubon.org/news/possib...ecker-footage-breathes-life-extinction-debate
Would still be interesting to see all the videos and hear all the recordings.
Fascinating stuff. I’ll limit myself to suggesting that the paper is remarkable.
https://www.audubon.org/news/possib...ecker-footage-breathes-life-extinction-debate
Would still be interesting to see all the videos and hear all the recordings.
Fascinating stuff. I’ll limit myself to suggesting that the paper is remarkable.
Farnboro John
Well-known member
You and me both...
The trouble is that the Ivory-billed Woodpecker has stopped being a subject of scientific investigation and become an object of faith. The world is divided into believers and the rest, and if one questions a believer objectively then "burn the heretic" rhetoric and aggressive language erupts immediately.
There is no evidence that will stand the remotest smidgeon of scrutiny. Therefore nobody can write a decent paper: you can't make bricks without straw.
John
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. His paper is available here. His statistics for the Pileated are based on data obtained from five locations and 121 total flap cycles. 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. It would be fairly easy for anyone to check Tobalske's statistics for this fairly common and widespread species. Tobalske concluded that the bird in the video is a large woodpecker. Only two large woodpeckers occur north of the Rio Grande, but the flap rate is about ten standard deviations greater than the mean flap rate of the Pileated. It follows from those facts that the Ivory-billed is the only remaining possibility, and the high flight speed, narrow wings, swept-back appearance of the wings, and prominent white patches on the wings are consistent with the Ivory-billed but not the Pileated. Observations that are supported by data matter to scientists, and the video documents that I had an ideal vantage point from close range and directly above for observing the definitive dorsal field marks. I saw the white stripes on the back, the black leading edges on the dorsal surfaces of the wings, and the white trailing edges on the dorsal surfaces of the wings.
I totally agree that Tobalske missed an opportunity. How often does a scientist get an opportunity to apply an approach that he developed to help resolve an issue that was featured on the cover of Science? Tobalske initially agreed to publish a paper with me, but he suddenly backed out, perhaps after sensing the considerable heat surrounding this issue. Tobalske's comments on the paper appear in my papers, and there is a discussion of the politics in the latest paper. All of this is discussed in this lecture. Think I'm exaggerating about the politics? Then go to p. 889 of the August 17, 2007, issue of Science, where John Fitzpatrick is quoted as saying, "Nobody else had the balls to do it." That is a remarkable quote to appear in a science journal, and it comes from arguably the most eminent ornithologist in the world, but it succinctly sums it up. I agree with Fitzpatrick about the politics, but I don't feel that one should need courage to stand up to it. If anything, such nonsense makes me more determined. As discussed in my latest paper and in the lecture, folly has also had an impact on this issue. In my opinion, the first step that is needed in the interest of this species is to put an end to the folly and politics that have undermined this issue for decades.
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.
The link that you provided shows only one of numerous events that appear in the videos. It is not necessary to have clear video footage to resolve characteristics such as flight path, wing motion, flap rate, flight speed, behaviors, body proportions, and partial field marks. All of the characteristics discussed in the analysis of the videos are unquestionable resolved in the videos. All of the events in the videos may be studied in movies in the supplementary material of the second and third papers listed near the top of the page here. If you click on Playlists at the top of the page, there are lectures on the videos.
I will be traveling for the next few weeks and might not be able to respond to questions for a while.
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.
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
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
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
Farnboro John
Well-known member
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
DMW
Well-known member
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
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.
DMW
Well-known member
Not nearly as many as you are missing, though... such as even a shred of credible evidence.
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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