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Figure 3 | BMC Biology

Figure 3

From: Video analysis of the escape flight of Pileated Woodpecker Dryocopus pileatus: does the Ivory-billed Woodpecker Campephilus principalis persist in continental North America?

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.

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