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Resolution: standard / high Figure 3.
Direct comparison of 36 frames from the Luneau video (selected frames in order from
183.3 ms to 966.7 ms; top line of each row) with equivalent frames from the fourth
flight of Pileated Woodpecker in David Nolin's video (all of frames 754–789, bottom
line of each row). The fourth escape flight from David Nolin's video was chosen because it most closely
matches the trajectory of the bird in the Luneau video. Luneau data was presented
at twice the frame rate of the Nolin video (which was a standard 29.97 frames s-1), so not all Luneau frames are shown here. The frames in each case start at the midpoint
of the second wingbeat after take-off, and continue to almost the midpoint of the
ninth wingbeat. Because after the fourth wingbeat, the Pileated Woodpecker in the
Nolin video slows its rate of flapping, the two comparisons are not to the same timescale
(Pileated sequence = 1.08 s, Luneau sequence = 0.78 s). White squares at the top of
the Luneau video sequence indicate an omitted frame. The Pileated Woodpecker flies
consistently obliquely away to the left, whereas the Luneau bird initially is flying
obliquely away to the right. For every field, in sequence, of the Nolin Pileated video,
an equivalent frame, in sequence, of the bird in the Luneau video is available. In
most frames, the similarities are striking, and in no case is there a clear plumage
feature on the bird in the Luneau video that is incompatible with the known Pileated
Woodpecker. In contrast, note frame 350 of the Luneau video, which unambiguously shows
the wing patterns of a Pileated Woodpecker. Reproduced from [1] with permission from
David Luneau.
Collinson BMC Biology 2007 5:8 doi:10.1186/1741-7007-5-8 |