An article in Nature contained this snippet:
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And some authorities say that there is unpublished evidence that helps prove that the bird in the [Luneau] video is a pileated woodpecker. They are referring to a 1953 film of a flying imperial woodpecker (Campephilus imperialis), a species extinct in its home range of western Mexico. Some years ago, Lammertink secured a copy of the film, which had been taken by a birding enthusiast. It was among the evidence shown to ornithologist Michael Patten, research director at the University of Oklahoma's Sutton Avian Research Center in Bartlesville, when he visited Cornell in June.
Ornithologists generally agree that the imperial woodpecker is a sister bird to the ivory-billed, with many similar characteristics from coloration to the distinctive double-rap. But Patten was struck by the imperial's flight patterns. "As soon as I watched the film," he says, "I was absolutely certain they didn't have an ivory-billed woodpecker. The bird in the film flies utterly differently to the one in the Cornell video."
Fitzpatrick is not troubled by the film of the imperial woodpecker, arguing that it sheds little light on whether his video shows an ivory-billed. "They are like apples and oranges," he says of the two videos, because of different camera angles and stages of the birds' flights.
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Since no video exists of a flying Ivory-bill, the Imperial Woodpecker video is a critical piece of evidence. In fairness, I think Cornell should make the Imperial video publicly available.