Jumping ahead a bit here, but there are some fundamentals about this that are rolling loudly in my head...
First, some starting points for understanding the black and white of the video:
White bleed, focus, etc.: Much reference has been made to the video exhibiting "white bleed," a contamination by excess white of the pixels surrounding a bright white pixel. But look at the edges of the tree trunks as they pass in front of bright sky, then gray background trees, and you will see that there is not really any white bleed. It has also been said that the video is poorly focused. Close up examination of the patterns of tree trunks shows that this is not the case, either. What the video is, pure and simple, is pixelated
, nothing more. The illusion of poor focus is an artifact of the video presentation, in which the pixel edges are softened to make the image look less jarring and jagged. The pixels on that bird are HUGE, about 3 cm across early on, and larger later. This simple pixelation is plenty adequate to account for all the crappy resolution of the images. The other factor killing resolution is plain-and-simple motion blur. This is what causes the white expanse on the underwing to appear larger than it actually is, and obliterates details of the underwing. Go through the arithmetic:
The pixel resolution is about 3 cm or worse. To this add motion blur of several more centimeters on the wings (more than 10cm near the tips in some frames). We're not going to see things narrower than 5-10 cm that are aligned perpendicular to the wing's motion. Now look at the sizes of the underwing features that would differentiate the two species: The Pileated black trailing edge is about 3-5 cm wide; the Ivorybill medial black bar is of similar width. And these wings are not oriented face-on to the camera, so the apparent width of these features is even less than this. So of course
these features are completely unresolvable in this video. Either species would be expected to show a big white blur under its wing and nothing else. In the CLO analysis they argue that the Ivorybill black bar would be obliterated, but the Pileated black trailing edge should be visible. Given that the two features are of similar width, this is argument does not hold up.
The one black feature of the underwing that is visible consistently is a black wingtip. This is especially clear in the second half of the downstroke of many frames early in the flight sequence, where it is smeared into a consistent black arc. Bevier and others have argued that this is a specific Pileated characteristic, and its presence is a key point they use to conclude that the bird is a Pileated. This makes no sense, however. Both species have black wingtips when viewed from below. The distance from the wingtip to the distal end of the underwing white is quite similar in both species, comprising about 20-25% of the total wing length. I do not understand, therefore, why the presence of a visible black wingtip provides any information at all to identify this bird.
Conclusion (and starting point for further analyses): The underwing pattern of the flapping wings in the Luneau video does not provide any information at all to help determine the species of the bird. Both species would be expected to show white underwings with black wingtips and no other markings under these conditions.
But what about the black wing edges that are visible in these early frames? Other than the wingtips, they are artifacts. They are not consistent between frames, and they appear both on the trailing and leading
edges of the wings with approximately equal frequency (neither species should show black on the leading edge of the underwing except at the tip, where both should show it). They also frequently align with darker areas in the background. The blurred wing images are semi-transparent, and they often meld with the background deceptively. The black spots on the wing edges are garbage, noise, useless; not information.
So, I have just thrown out the most prominent plumage characteristic in the video, the big fat white underwing with a black tip, concluding it is useless for identifying the bird. What is left? Good question. I don't think (yet) that the answer to that is "nothing;" but I make no guarantees.