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I did some screen captures of the manybirds.com Pileated video
and took some corresponding captures from the Luneau
video. I was looking for frames that showed the wing
pattern, which tended to be, in the Luneau video, at
the beginning of a downstroke. Looking at the Luneau
video (just the web Quicktime version--I don't have
the DVD), I can see several frames where what appears
to be a dark trailing edge to the woodpecker's wings
is visible. I can see corresponding frames in the
manybirds.com video of the Pileated. I was
particularly struck by a couple of frames where there
is an apparent dark "V" formed by the trailing edge of
the wings in the Luneau video. This is very prominent
in the manybirds.com video, which is, of course, in
focus.
I have done no editing to the web version of the
Luneau video--just captured and cropped individual
frames. For the manybirds.com video, I rotated some of
the frames and/or flipped them, to make the bird point
in a similar direction to the bird in the Luneau
video. I've also added little red dots, "reference
points" to what I think are corresponding parts of the
bird in each frame. The pattern of these should be
self-explanatory on the frames.
I will freely admit that this sort of thing is rather
subjective. Also, compression artifacts can cause
problems in digital video, and the fast motion of the
woodpecker's wings (both videos) and poor focus (Luneau
video) can really cause problems in interpretation.
The red arrow on the Luneau frames shows what I think
to be the motion of the bird at that time--it flies
right at first, then turns and flies up and away
angling to the left.
Posts
15 comments:
I'm impressed!
This is an interesting post in that it provides material for discussion:
The first thing I'd like to point out is that it appears the camera-to-bird angle is different between these two videos. In the Luneau video, doesn't the bird start out just barely higher than the camera, so that you're basically looking right up its cloaca? In the Pileated video, the bird is at the top of the tree with the camera looking up at it, correct?
Given those differences in camera angles, I think you'd end up looking at the underwings almost constantly in the Pileated video. There's a greater chance of seeing the upperwing in the Luneau video. So these two videos might not be as comparable as you think.
Does anyone know how much the secondaries would move as the bird flaps it's wing? (I'm referring to how much they'd flex relative to the rest of the wing.) I'd like to see a video of a Pileated in a more comparable position relative to a camera. Jumping puddle ducks from a pond might also get comparable video. You could see how often the speculum is visible.
The point of doing this would be to see how often you'd see the upperwing when the bird flies away as the one in the Luneau video. The thing that strikes me about the Luneau video is that there doesn't seem to be any frames were there's indisputable black secondaries. In all the frames in this post, it's arguable if there's really a black trailing edge at all (discussed below).
Unless it's shown that a bird flying like the one in the Luneau video will constantly show its underwing, I would expect to see a lot more black. I would expect the wing to flash black-white-black-white as it flapped, but in the Luneau video, there's always a large amount of white in every frame that I've seen.
A few comments about some of the specific frames: in the first box, the Pileated has an equal amount of black around the secondaries and primaries. In the Luneau video, you only see black around the primaries (or what appears to be the primaries). If the white is bleeding in the video due to it being out of focus (which would block the black of the secondaries) why isn't it doing the same in the primaries? (Maybe the secondaries are flexing in such a way that their pointed more or less at the camera, which could cause them to disappear, but they aren't doing that in the Pileated video; though as I said, the camera angles are different.)
Also, the "black trailing edges" in several frames, particularly the first two and last two, appear to coincide with dark lines created by trees in the background. Difficult to tell what's responsible for those dark spots. Also note that there is no dark trailing edge in any of the frames of the second box. According to the red dots, the black is only from the primaries.
Despite all this, it does nothing to discount a Pileated with white secondaries. This is where the only thing you have to work with is the flight style of the bird...but I doubt anyone is still reading this at this point, so I'll quit.
These are really good comments, sb--I read them all!. (OK, I confess, I'm the frame-grabber here.) I'll have more time to work on this after Christmas. I'll do some additional frame grabs of the up-strokes in both videos--maybe I'll even get a chance to go out in the woods and get my own blurry video of a Pileated! I really wish I could get a blurry video of an Ivory-bill for comparison.
I highly recommend downloading each video to your hard disk (for personal use, of course) and stepping through each of them frame-by-frame. It is much easier to see the sequencing of flapping wings that way. Some versions of Windows Media Player do not let you do this for Quicktime videos--if so, you can get Quicktime player as a free download from Apple.
I agree that the camera angles are not completely comparable, but in both cases, the camera was below the bird--Luneau's was mounted very near water level on the canoe, but it is much more on a level with the bird--absolutely.
In both videos, I believe you see mostly the underside of the wings. The upper side is visible only briefly in Luneau's video during the very rapid up-stroke, when the wing is mostly folded. You can just see this in the video, I think, and the upper wing surface looks dark, but it is very hard to say.
For that matter, there should be a dark line visible on the underside of an Ivory-bill's wings--see Sibley's illustrations. The Science paper said this was not visible due to blurriness. I found that unconvincing--as they claimed in the same paper to see more subtle marks, such as white on the dorsum. Certainly the dark primaries are visible on the video, and they are relatively small.
I agree that it is hard to sort out vegetation from the bird in the Luneau video. It is perhaps more obvious if you do the frame-by-frame thing. For instance, the body of the woodpecker is always visible as an oblong dark dot moving against the background, despite the poor focus and the vegetation. When you follow this, one can sort out the sequence of up-strokes and down-strokes. That is what the Cornell researchers did in their paper.
And yes, I think the dark secondaries are sometimes not visible in Luneau's video because they are pointed back at the camera. What I find very curious is that a prominent dark line suddenly pops up between the white wing linings at the beginning of the downstroke, when the wings are held straight up over the bird. This is real obvious in the manybirds.com video. It does not look like vegetation in the Luneau video to me--again, more obvious if you step through frame-by-frame.
Then there is size. There are real questions about the analysis of size of the bird in the video. Reading the original paper, I found it very difficult to follow. See this post by Chuck Hagner, editor of Birder's World for some discussion of that.
If I had to make a bet on the Luneau video, I'd say it is a normal Pileated. I just don't see anything inconsistent with that. But hey, like all of us, I'm just somebody sitting in front of a computer!
I'm an agnostic on the Arkansas Ivory-bills, though I want to believe--I've wanted to see the IBWO my entire life. I found some of the sight record descriptions convincing, but not the video. I wasn't very impressed by the Cornell reconstructions using models--the wings are rigid, don't fold during the upstroke, and are not blurred due to a normal rate of wing-beat. I don't understand why they could not go and get videos of a Pileateds for comparison--they are common in Arkansas, and in New York for that matter. I feel they did not try hard enough to disprove their own interpretation.
Maybe I'll be able to post some more after the holiday. Best wishes to all.
Some comments on the latest from Patrick Coin:
Regarding the absence of a dark line on the underwing in the Luneau video: you could expect the white in the other parts of the underwing to bleed obscuring this feature, either due to it being out of focus or due to the shutter speed being too slow. I could turn your argument the other way: I’d expect to see obvious black secondaries of a typical Pileated. Aren’t the black secondaries of Pileated much broader than the black in the center of the Ivory-billed’s wings? The black “trailing edges” are so thin in the Luneau video as to be debatable as to whether they’re really present or if it’s a video artifact, IMO.
Regarding the white spot on the dorsum: I haven’t mentioned it previously because I don’t think there’s enough there to work with. I’ll consider it in the future if there’s some way that you could demonstrate you’re actually looking at the correct part of the bird’s back, but the video is too blurry to really be sure how the bird’s body is exactly oriented. However, I don’t think that it’s fair to compare that feature with the black line in an Ivory-billed’s underwing. There is so much more motion of the wings compared to the body, so there’s obviously going to be more blurring involved. Also, in video, white bleeds into black, not the other way around, so the white on the bird’s back isn’t going to disappear due to the video being out of focus. On the other hand, the black will. Yes, the black primaries are visible, but they represent a larger area of black than the black line on the Ivory-billed’s coverts.
I will have to look at the actual video frame-by-frame when I get the chance. I’m willing to entertain that there might be some black on the trailing edge in the 3rd box, but I’m not really seeing it in the other boxes. (Like I said, in those other boxes, they appear to coincide well with vegetation in the background.) I’d like to see how consistently this feature appears.
You mention that the black is “prominent” at the beginning of the downstroke (when the wings are held straight up, right?). I guess that could be explained by the secondaries flexing “upward” at that point, becoming more visible to the camera, but wouldn’t a similar, maybe larger, flash of black be expecxted at the beginning of the upstroke, too? I would expect that the secondaries would flex downward at this point, revealing the upperwing (in which case the wing should be largely black in the video), but I really don’t know if this is what actually happens. Video is needed to confirm or refute that.
I think the second box in the post is open to debate. Look at the Pileated video. Relatively little white is visible. It’s brightest at the base of the primaries. The underwing coverts actually look black or at best dark gray on my monitor. Overall, the wings look pretty black. Also notice that proximal half of the wings look pretty thin because they’re more or less parallel to the camera angle. Now, consider the similar frames from the Luneau video. The camera is much closer to being directly behind the bird. (There’s no tail sticking up above the body as in the Pileated video, which I think confirms the difference in angles.) Assuming the wings are in the same position as in the Pileated video, the camera at this angle should therefore show even less of the underwings. It might even be expected to show the upperwings. Yet there’s much more white than in the Pileated video. Granted, the effects of motion and blur plus the fact that the Pileated is probably more underexposed than the bird in the Luneau video due to the bright background all cause problems with the interpretation, but still, given the example of the Pileated video, I’d expect the proximal half of the wing to be black in the Luneau video. (But yet again, I’ll say that I’d like to see some other videos to confirm or refute my expectations.)
Overall, my problem with this being a typical Pileated is that you have over 3 seconds of video (if I recall correctly) of the bird flying away, which probably gives you about 100 frames, and yet there doesn’t seem to be a single frame where the wings look mostly black. Intuitively, you’d think that would happen at least a couple of times. Of course, intuition is one thing, video confirming this is another.
Also, if this is a typical Pileated, what do you make of the frame of the bird perched in the Luneau video shown in a recent post? If that’s the underwing of the bird as it’s beginning to fly, I think you’ll have to agree that the left-most portion of white, the part with the smooth edge, is the p10, the outermost primary. The edge is too smooth to be a video artifact. Therefore, isn’t the part of white where it “indents” to the right the wrist of the bird? With those assumptions, it looks like the bird is dropping its wing downward as it’s opening it. Would this be normal? From what I’ve seen, when a woodpecker takes flight, it first leans in the direction of flight and then throws it’s wing open, usually lifting it upward or at least pushing it outward (parallel to the ground). The Pileated frame appears to confirm this. Furthermore, there appears to be an equally smooth edge of a black area above the left-most bit of white, suggesting that it’s also part of the bird (though considering what I’ve said about your black wing edges, I guess I’m can’t really safely make that leap). Maybe the uppermost white is actually the wrist, but as I said, it looks like that smooth left edge is real, not an artifact. And if the uppermost white is the wrist, why isn’t there a smooth edge of white below it? I’d say these things argues strongly against the upper part of white being the wrist.
One thing about the size issue: I haven’t brought that up because I don’t buy into it at all. The video is way to blurred to confidently measure fine-scale differences in lengths. It might be OK if we’re talking about differences of 6 inches or more, but I don’t see how you can claim to see differences of only 1-3 inches.
I just want to reiterate that I’m not trying to argue that the Luneau video is not necessarily confirmatory for Ivory-billed. However, there’s enough here that, at this point, it’s far from clearly being a typical Pileated. Other than the flight style of the bird (a constant rate of fast flapping), it would be very difficult to convincingly eliminate the possibility of an aberrant Pileated. (BTW, I checked out the Chuck Hagner post, and found this regarding the “population” of aberrant Pileateds: “Rosenberg said that there were reports of such birds, and that he had seen a photograph of a Pileated that was missing upper-wing coverts. The missing feathers exposed more white than usual on the bird’s wing. Rosenberg said that the resulting pattern was not symmetrical, and stressed that he had seen nothing to contradict the team’s conclusion that the Luneau bird’s wing pattern was that of an Ivory-bill.” Note that there was no mention of Pileateds with white secondaries and no mention of photographs of such birds. But it still would be nice if Cornell would release the photograph Rosenberg referred to.)
I understand the proposition that in science, it’s up to the person making the extraordinary claim to provide the proof. I also understand how this video, given current knowledge, may not rise to the level of absolute proof. However, this isn’t a typical situation. If you argue about whether birds evolved from dinosaurs, there’s no need for urgency. It doesn’t matter if it takes decades to come to a conclusion. This is different. Look back at the history of the Ivory-billed or other extinct species like the Carolina Parakeet. How many times did the out-of-hand dismissal of a questionable sighting or just outright inaction doom a population or entire species?
If there’s any validity to my arguments (which I don’t expect all of you to agree with, though I think thoughtful consideration will show that there’s something to them), there’s enough here to cast doubt that the Luneau bird is a typical Pileated. When you couple that with information from the various sightings, you start to have a decent case for the existence of at least one Ivory-billed, and there is potentially so much to lose if you don’t act on that.
That’s enough for now. Time for the holidays.
BTW, I just want to point out that the last couple of paragraphs of the last comment weren't directed at Patrick Coin but were intended just as general commentary as to why I think the claim of an Ivory-billed in Arkansas should be given a little more leeway than a "standard" scientific claim.
sb wrote: "...you start to have a decent case for the existence of at least one Ivory-billed..."
I think it's important to remember that if any Ivory-bills survive today, there would almost certainly be 20 or more birds, rather than one or two lonely individuals. I think chances are very nearly zero that such a population could have avoided being clearly photographed for so many decades.
There's more at this link
Tom said...
" sb wrote: "...you start to have a decent case for the existence of at least one Ivory-billed..."
I think it's important to remember that if any Ivory-bills survive today, there would almost certainly be 20 or more birds, rather than one or two lonely individuals. I think chances are very nearly zero that such a population could have avoided being clearly photographed for so many decades."
Now you're directing the conversation away from the video. I know you think the bird in the video is a Pileated, so go ahead and contradict my arguments. For example, tell me how the perched bird in the Luneau video is actually a Pileated showing it's underwing. You say it "roughly corresponds", but give me some details on how it actually does correspond. As I stated in my arguments, the wing appears to be in a very odd position if it is in fact a Pileated's underwing being extended for flight.
But getting back to your comment. It _is_ troubling that there aren't multiple photographs of Ivory-billeds. Cornell may be making a case that there could be a sustainable population, but I'm not. But that doesn't mean there couldn't be one individual out there, however extreme the odds may be.
"...give me some details on how it actually does correspond..."
Sorry, I've already given you everything I've got regarding that perched bird. I can't see enough detail to go any further...
Cornell isn't saying that the video could be an Ivory-bill, or the sightings looked like glimpses of Ivory-bills, they're saying that it is 100% proven.
As far as how the perched bird shows a Pileated with a raised wing, I think there are photos illustrating it on this blog. The shot is so blurry, it is simply guesswork. Is the blur a Sasquatch or is it a black bear? No, I can't PROVE it's a black bear...
I think most reasonable people would agree that there's some pretty good arguments for saying the video is a Pileated woodpecker. Since Pileateds are a dime a dozen, it sensible to assume the video is a Pileated unless proven otherwise, not the other way around.
For the life of me, I can't understand how anyone could say that Cornell hasn't made an extraordinary claim, or that they've provided extraordinary proof.
At the end of this search season, I think most people are realizing that Cornell won't have "the photo," and the reason they won't get the million dollar shot isn't that Tanner was wrong or these birds have become quiet or they've become wary or the terrain is so brutally tough, it's that there's no Ivory-bill to photograph.
Actually, Patrick, I was standing in flat, marshy country when I videotaped the Pileated Woodpecker in May 2000 (shown at www.manybirds.com). I was 150-200 feet from the bird, which was perched 15-20 feet off the ground. I read that Luneau's bird was perched 4m above the bayou when it was taped from 20m using a GL2 set about 1m above the water, so the angle in the clips may not have differed much from each other.
sb said
Regarding the absence of a dark line on the underwing in the Luneau video: you could expect the white in the other parts of the underwing to bleed obscuring this feature, either due to it being out of focus or due to the shutter speed being too slow. I could turn your argument the other way: I’d expect to see obvious black secondaries of a typical Pileated. Aren’t the black secondaries of Pileated much broader than the black in the center of the Ivory-billed’s wings? The black “trailing edges” are so thin in the Luneau video as to be debatable as to whether they’re really present or if it’s a video artifact, IMO.
Yup, those putative black trailing edges are thin. I'd hypothesize exactly what the Cornell authors said in the Science paper--the blurring and poor focus cause bleeding of white into the black. Of course, that's the basic problem with the Luneau video--it is so poor that very little definitive can be said. That was my point in looking at the Luneau video in comparsion to the manybirds.com video of a Pileated. The authors from Cornell look at one set of frames and they see an Ivory-bill. Look at certain other frames and the blurry Luneau bird looks like a Pileated.
I think the second box in the post is open to debate. Look at the Pileated video. Relatively little white is visible. It’s brightest at the base of the primaries. The underwing coverts actually look black or at best dark gray on my monitor.
I believe the manybirds.com video of the Pileated is much more stronlgy backlit than the bird in the Luneau video. That makes the underside of the wing appear quite dark.
Overall, my problem with this being a typical Pileated is that you have over 3 seconds of video (if I recall correctly) of the bird flying away, which probably gives you about 100 frames, and yet there doesn’t seem to be a single frame where the wings look mostly black. Intuitively, you’d think that would happen at least a couple of times. Of course, intuition is one thing, video confirming this is another.
Yes, excellent point, and that has bothered me. I went through most of the Luneau video and captured every frame where the bird is fairly close. I placed them in rows by wingbeats, each row starting with the flash of white when the wings are held overhead, at the top of the upstroke. It was surprisingly easy, and each of the eight wingbeats taking almost exactly the same number of frames--typically seven, so I got about 56 frames. (This shows, I believe, one very clear shot of the dark trailing edge, and the frames on either side don't show any vegetation resembling that dark stripe--it moves with the wing--more later.) The wings flash white on most frames, except on the last couple in each beat, which is clearly the (very rapid) upstroke. The effect is quite obvious in the video--the bird almost disappears for a couple of frames during the upstroke. The file with 56+ frames is too large to post in-line on a Blog. I'll try to figure out some other way to show it to interested parties.
I think the reason for all the white is that we are behind the bird. A bird wing is a three-dimensional, adjustable airfoil, and a wing stroke takes place in three dimensions--besides the up-and-down motion, there is some fore-and-aft motion. I believe the bird is pushing its wings back during the downstroke, scooping with its wings. The result is that, from behind, the Luneau video camera saw the underside of the wide-spread wings, mostly white. The dark upper surface of the wings is really not seen because the wings are folded on the upstroke. This is, again, where I think reconstructions with models fail--they don't recreate the real nature of a wing-stroke. At least, I did not get that idea from the Science paper. The photos I've seen of the models looked like the wings were fixed and just flapped up and down.
As you have mentioned earlier, it would be really good to see some video of live Pileateds at similar angles to the Luneau video. Seems that should have been done for the Science paper, but it was not.
Also, if this is a typical Pileated, what do you make of the frame of the bird perched in the Luneau video shown in a recent post?
I always thought that first flash was the white wing lining as the bird raised its wings to take off, with most of the bird invisible behind the tree. To me, it is too blurry to make out anything definitive. Both IBWO and PIWO would be expected to show that mostly white lining. I'm not competent to go into the details you and Tom have been discussing. I'm still confused about a diagram in the Cornell paper--it seems to imply that flash is the back of the wing--that has never made sense to me. Again, I am a birder, not an ornithologist!
BTW, I just want to point out that the last couple of paragraphs of the last comment weren't directed at Patrick Coin but were intended just as general commentary as to why I think the claim of an Ivory-billed in Arkansas should be given a little more leeway than a "standard" scientific claim.
I did not your comments as directed at me--no offense taken. I agree with the "leeway" viewpoint. I worry, however, that some of this might end up being counter-productive by, for instance, angering the hunters who have protected the Arkansas habitats in the first place. (I'm not a hunter myself.) I also worry that too much IBWO hoopla may distract people from other more important conservation issues. Of course, all the hoopla may get more of the public interested in bird conservation, and that's a good thing.
My interest here: As a lifelong birder (since age 5--I'm 46), I'm trying to work through this. I've been hearing rumors of Ivory-bills since the 1960's, and they just never have seemed to pan out with birds that anyone could actually go and see. I've been on Cloud Nine ever since the Arkansas IBWO was reported. My initial reaction was that it was too good to be true, and I'm slowly coming back to that viewpoint. We're coming up on almost two years since the spring 2004 "flurry of sightings", and the blurry video is still much of the evidence out there.
I have some additional comments on the video, but let me say that this will be my last in a long-time, maybe forever. I'm traveling for the holidays, and I also find the fact that only Patrick Coin has demonstrated a willingness to actually discuss the videos in-depth quite telling about the attitudes of this blog, despite claims that the arguments have been taken as far as the can go to the contrary. But don't worry, I won't let the door hit me on the way out. I didn't expect any different.
OK, Patrick, here are my comments on the video. I'll make them as quickly as possible:
1) The camera angle in the two videos: Even if the camera angle was similar as the birds left their perches, I don't think it remained similar beyond that point. The bird in the Luneau video was apparently only several feet above the water. Therefore, it had to immediately gain altitude as it flew off (which may account for the very rapid wingbeat, though the fact that it's continuous throughout the entire video seems untypical for Pileateds). On the other hand, the Pileated in the Manybirds video was 15-20 feet off the ground as it began flying. Birds typically drop from a perch and use gravity to gain momentum. In the frames from the second box, the tail appears to be "above" the body as it flies off. It also appears that in all, or almost all, frames you don't ever see the bird's back. Both of these things indicate that the bird is losing altitude at the beginning of fight.
Therefore, it appears that the angle of the birds' bodies in relation to the camera differ between the videos. (Even Tom Nelson says he's seeing the back of the Luneau bird -- see point 4 of his "Luneau video analysis" from Sep 20.)
2) A more in-depth analysis of wing motion is definitely needed. I don't disagree with the main points of Patrick Coin's argument on this point, but we really need a comparable video to see what's actually going on. As mentioned previously, there's obviously black at the wing tips. If this part of the wing flexes more on the downstroke than the secondaries do, I can see why this area of black would be more prominent in the video. But I'm still troubled by the lack of any truly obvious black on the secondaries in any(?) frame.
3) The perched bird: while it is definitely blurry, take another look at the left-most portion of the white blob. It has a very straight (actually slightly curved, maybe I should say it's a smooth edge) edge compared to anything else in that frame. (It also seems to merge with the left edge of the black blob above it.) This edge is so regular over a relatively long distance as to not be an artifact of the video. Assuming that it's actually something that's straight on the bird, you're really only left with two possibilities. It's either the top side of the folded wing (i.e., the bird is still perched on the tree and hasn't opened it's wing at all; I think there's a drawing depicting this in the Science paper) or the outermost primary on the underside of the wing. If it's the underside, the wing is stretched out in a really odd way.
That's it for now. And don't worry about being birder and not an ornithologist. I think birders are more qualified for this stuff. :)
Patrick and SB's technical but very civil dialog just goes to show how amazingly borderline the Luneau video is! Patrick, I'd be happy to post your 56+ frame file, perhaps as a link within this page: www.manybirds.com/pileated.htm and I would ask Luneau for his permission.
Several points:
Your bird is clearly viewed from below. The Luneau bird is nearly on the level and rising relative to the camera. The Luneau frame that is interpreted as clearly showing extensive white trailing edge of upper wing on a downbeat is in an orientation that it is VERY difficult to imagine a realistic scenario in which that could be the underside of the wing. Your bird begins well above the camera and remains well above the camera.
Second point: the positions of the tree branches indicate the pileated frames have been rotated in different directions to match them to the Luneau bird, which is shown with a fixed frame orientation. This suggests to me that the postures of the two birds in corresponding frames are in fact NOT the same. If they were, why would this rotation in different directions between closely-spaced frames be necessary?
Bill Pulliam
Anonymous ( Bill Pulliam ) said...
Several points:
Your bird is clearly viewed from below. The Luneau bird is nearly on the level and rising relative to the camera. The Luneau frame that is interpreted as clearly showing extensive white trailing edge of upper wing on a downbeat is in an orientation that it is VERY difficult to imagine a realistic scenario in which that could be the underside of the wing. Your bird begins well above the camera and remains well above the camera.
The orientation of the wings in any given frame is more obvious when one looks at the whole sequence. I recommend going through the Luneaa video frame-by-frame and trying to count wingbeats. The top of the stroke is obvious due to the flash of white on the underside of the wings above the dark body--that flash would be there for either PIWO or IBWO.
That frame with the wings scooped down, showing a lot of white is still in a downbeat, as far as I can tell. I think it is important to remember that the wings are likely rotated and scooping backwards in this powered flight--that might show the underside from behind. Though it is hard to know the specifics in this situation, I do know that birds do not just beat their wings up and down! I think that was an unrealistic part of the simulations used in the Science paper, the way I read it.
The upstrokes in the Luneau video are very rapid--just a couple of frames in the web version. In what I interpret to be the upstroke, the wings just seem to disappear. I'm thinking that could be due to the uppersides being black--a Pileated. I'll try to post the entire sequence somewhere, with appropriate permission, and perhaps the interpretation (or misinterpretation) will be more clear.
Second point: the positions of the tree branches indicate the pileated frames have been rotated in different directions to match them to the Luneau bird, which is shown with a fixed frame orientation. This suggests to me that the postures of the two birds in corresponding frames are in fact NOT the same. If they were, why would this rotation in different directions between closely-spaced frames be necessary?
I wasn't trying to be deceptive, just to see how well frames of a video of a known Pileated might fit the Luneau video. It is hard to tell the orientation in any given frame in the Luneau video because of the poor focus. The bird does turn during the video clip--it starts out flying to the right and turns and flies away and to the left. The turn happens early in the video clip, and the focus is so poor it is hard to gauge the bird's orientation in any one frame.
I certainly don't pretend to have any definitive answers--as I said, I was just diddling around, trying to understand what was going on with the famous video. I see some frames consistent with a Pileated. A whole lot hinges on whether one is looking at the underside or upperside of the wings in the video in any given frame.
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