Woodpecker wingbeats without comment
Of interest to some --
I did some counting and created the following graph, which I present with no discussion other than describing how I made it and a bit about statistical significance. If it is truncated or too small you can right-click or ctrl-click on it to open it in a new window:
The Pileated source videos are the ones posted by Cornell and by David Nolin. I found a total of seven of these useful, wth between 2 and 15 wingbeats resolvable. I defined the beginning of each wingbeat as maximum upward wing extension. I counted in whole frames, so the temporal resolution is 17-33 ms depending on the source footage. For Luneau, I took the "extended wing" interpretation of the frame in which the bird first appears to the left of the tree trunk, not the CLO's "folded wing" interpretation. Thus, that is counted as the zero time point, the start of the first wingbeat. Using the other interpretation would decrease the Luneau times by 33 ms or less. I used only the first 10 wingbeats of the Luneau video, as they are the ones that are agreed to be clearly discernable.
All Pileated comparison videos are of perched birds taking off, as is the Luneau video. Only three sequences show the Pileated in frame and on the wing for 10 full wingbeats. This small sample size precludes any meaningful statistical analysis as to whether the Luneau bird is an outlier or within the expected range of variation of the Pileated, a fact that must be borne in mind while examining these data. A rigorous analysis would need many more Pileated videos in which the bird remains on the wing for 10+ wingbeats, prefereably longer. Ideally there would be multiple videos of Pileateds that remain on the wing in full flight for the full three seconds or so that the Luneau bird does.
I have presented the data in this format (total elapsed time versus number of completed wingbeats) because it gives the best resolution of the individual birds and it is the least sensitive to judgement calls as to which frame represents the beginning of any particular wingbeat. A plot of individual wingbeat durations produces a confusing jumble of overlapping lines.
A note about comments -- please limit to direct discussion of the wingbeat data and its interpretation, without abrasive or hyperbolic language. No anonymous or pseudonymous comments. Thank you.