Sunday, June 17, 2007

I'm meant to be painting the ceiling.

Cyberthrush asks on his blog, and independently another (the other) reader has asked... whether Cornell have published that rebuttal they promised for my paper? And if they will be doing so?

Answer is (are) 'no', and 'I don't know'. But I hope they do. Deal was... my understanding is that the Fitzpatrick et al team were invited to publish a reply alongside
my paper at the time of publication, but the ms was not received in time, or at all. BMC Biology Editor has told me that if the rebuttal arrives, I will get chance to reply. So I expect to hear if something is in the pipeline, and I haven't heard anything yet. Of course maybe the rebuttal has arrived and is undergoing peer review before I see it. That is possible. I hope they go for BMC Biol, rather than somewhere easier like the end-of-term report. I've got a few things left behind for replies to replies, and Soggy-bottomed Bill and Dave Martin deserve acknowledgements to their comments, but I have wanted to wait until all the opinions are in.

While we're on the subject... here's another sketch called... YOU CAN'T HAVE IT BOTH WAYS. I thought Ivory-bills were meant to fly with shallow rapid wingbeats, unlike the deep floppy rowing beats of Pileated. Seems to have been a big thing made about that on the recent sightings from Florida and elsewhere, and several people comment on the Luneau bird flapping in an unusual manner for PIWOs. I've argued that all birds, especially big ones, PIWO and IBWO included will bow their wings and flap hard on take off, gaining speed and altitude, and a trip out birding (try it - it's fun!) will confirm that.

SO then you go here (Cornell video analysis site) and click on that video, representing the last clear wingbeat of the Luneau bird. It's meant to be showing the white on the back. I'm not sure what to make of the white. If you believe (as you have to if you want the Luneau bird to be an IBWO) that white bleeds when you want it to but doesn't bleed when you don't, then it's conceivable that this represents the dorsal stripes of an IBWO. Equally (as proposed by Sibley and colleagues) it could be white from the head, or light reflecting off a black back, or some other weird artifact. But ignore the white for a second. What the video has done by putting that last wingbeat on a loop has shown how the bird flies as it is relaxing into level flight. And looky here, it's flying like a PIWO?? Deep and floppy, and wings extended. So either IBWOs can fly like PIWOs, or that isn't an IBWO?? Comments please.

Before Bill starts... :-) I'm not yet committing on whether its me that wants it both ways, or the True Believers.


Bill Pulliam said...

Sorry, but you asked for comments...

The only place I've claimed that white doesn't bleed is around a corner out from behind a tree trunk (infamous frames 33 and 50). That seems like just common sense and basic optics, not trying to have it all ways. Yeah sure, really bright light can defract visibly around a tree trunk, but we're talking plumage here on a cloudy day, not laser beams or the unfiltered direct sun.

Theories about how birds could conceivably fly are lovely, but I compared the way real pileateds in real videos really DO fly under similar circumstances to the Luneau bird. That is, I compared initial wingbeats after launch in both cases. It's called empiricism. People ought to try it more often, rather than attempting to reason out what a bird should be and should look like from first principles starting from the Schroedinger Wave Equation. And besides, in that final wingbeat you talk about, the wing shape is hardly discernable at all. I can imagine that I see bowing in frames 2 and 3 just as easily as you can imagine that you don't. Gee... you skipped over the much clearer early wingbeats where the wing shape is indisputable, and picked one that is far blurrier and much less clear to make the point. Gosh, is someone trying to have it both ways?

By the way, I agree that the white on the back is nothing more than "interesting" since you can hardly tell wing from body, much less head from dorsal stripe. What appears to possibly be a black head in front of white back also looks exactly like another of those abundant black fringe compression artifacts (see how it aligns, inevitable, with the background shaddow?) that everyone else has tried to turn into black trailing wing edges. Not saying it is or it isn't, just saying I don't believe it can be told.

I do wish Cornell would come back up to the plate on this. After all, it's their video, not mine. I've never even claimed to have seen one of these freekin' birds yet I've still been awarded an honorary "crow."

Bill Pulliam said...
This comment has been removed by the author.
Bill Pulliam said...

Actually, on second thought, I think I CAN tell that the "black head" in that loop really is yet another of those black fringe artifacts and not part of the bird. It points the wrong way and moves the wrong direction relative to the bird to be real; and it points exactly along and moves exactly with the background shadow just like all the other edge artifacts do. Also the "black head" isn't consistently visible before or after this sequence. I remember it has always bugged me in that sequence that the bird's head and body seemed to be misaligned with its overall movement (head pointing a bit to the right, bird moving to the left); this explains that. I think the "white back" is probably something real on the bird, not an artifact or reflection; but what part of the bird? I don't think that can be determined.

See, I've also discarded one of the supposed IBWO field marks (the "black head" in front of the "dorsal stripes") as an artifact, not just all the supposed PIWO field marks!

Martin said...

Nice one. If it's OK with you I'll discuss this further in the main bloggy section