Closing out October, as most know, Cornell has released enthralling film from the 1950s of the (presumed extinct) Imperial Woodpecker in Mexico taken by an American dentist and amateur ornithologist of the day (the only known film of the species in existence). The full story here, from Cornell's "Living Bird" magazine, along with other links:
http://tinyurl.com/6ambbns
The more academic article from "The Auk" here:
http://www.birds.cornell.edu/Page.aspx?pid=2163
They have also put the film clip footage up on YouTube:
http://www.youtube.com/watch?v=Q0OCd6b1aXU
On the bright side, the historical story is fascinating, and the brief film clips are mesmerizing to a point of eeriness. For anyone who has followed the Imperial and Ivory-bill story in tandem it virtually sends shivers up the spine... and, also shrouds one's countenance with sadness.
The report is simultaneously a distraction from, and an incentive for, the more immediately-pressing Ivory-bill story. Perhaps it will inspire some of the remaining IBWO searchers, who's zeal might be lagging, to re-double their efforts, or even inspire others to begin anew.
Having said that though, it is again disconcerting that a single amateur on the back of a mule 55 years ago was able to attain film, at quite some distance and obviously with a 1950's camera, of an Imperial Woodpecker that clearly shows the white 'saddle' back, while 6 years of more recent effort with far better equipment, by far more individuals, with more leads, searching far more locales, for the Ivory-bill, has failed to produce such, either by a person or an automatic camera.
Beyond the sheer historical wonder of the report, Cornell argues that measurements of the Imperial's wing-flaps from the restored film lend credence to their original conclusions on the Luneau tape of a purported Ivory-bill:
"The bird maintains a fast wing-flap rate well into a flight. Data in this film contradict two arguments made about launch and flight behavior of large woodpeckers by Sibley et al. (2006), namely that in normal takeoff a woodpecker holds its tail against the trunk until after its wings are extended and ready for the initial down stroke and, secondly, that woodpeckers larger than the Pileated Woodpecker (Dryocopus pileatus) should flap more slowly than that species.
In fact, whereas Pileated Woodpeckers have been documented to slow to flap rates of 3.9 to 6.7 s–1 through wing-flap 8 postlaunch (Collinson 2007), the film shows that the Imperial Woodpecker could maintain a flap rate of about 7.7 to 8.3 s–1 at that phase of flight, despite having a body mass 2.4× larger than that of a Pileated Woodpecker."
Still, the single most important sentence in their 'discussion' section is the first one, which will too often be overlooked:
"The information contained in this 85-s film is scant and must be interpreted with caution."
Indeed it is. We are faced again with a whopping sample size of ONE (without a lot of contextual information), and attempts to draw broad generalizations from it. This would never be done in a study of human behavior, but is (egregiously) done too often with abandon in animal and field studies. Any conclusions reached pertain to a single bird in a specific context during a 2-minute point of time in its life... perhaps they apply more broadly... but it is difficult to know.
And I'm all for drawing any conclusions that can be reached ABOUT THIS INDIVIDUAL BIRD, but less confident of how directly such conclusions may apply to Ivory-bills. (Indeed, it's the same complaint I've long voiced for Tanner's observations of a half-dozen birds in a single locale being turned into conclusions that were then applied to all Ivory-bills everywhere.) The main point Cornell seems to wish to make is that it is POSSIBLE for a bird as large as the Imperial (and by implication the IBWO) to maintain a certain high flap-rate never achieved by Pileateds on available film (...ASSUMING you accept Cornell's analysis, and assuming the full range for Pileateds have already been captured and reviewed on tape accurately). And so it goes....
This film, held for an almost unseemly long time by Cornell (since 2006, through the end of the official IBWO search), has been restored, digitized, analyzed by their own people... who now, not too surprisingly, publish conclusions helpful to their cause (would they have even published the results if it were otherwise?) -- and I say that only because cynical sorts will wonder what exactly the lab folks were doing with that film for 5 years before acquiring results to their liking. The entire IBWO debate is polluted enough that skeptics may not take Cornell's conclusions or calculations at face value, unless the raw footage is independently analyzed by impartial third parties (...or else if skeptics themselves analyze it and reach the identical conclusions) -- unfortunately, neither Cornell, nor their critics, nor anyone else with a stake in the debate, are assumed to be objective, unbiased sources of analysis or review anymore, especially given a tendency to cherry-pick data to suit one's purposes. Cornell writes that they have 'allowed for possible inaccuracies in the framespeed of the film'... so, we have their word on that; might have been nice if they had brought in 1 or 2 of their serious critics to collaborate and concur on the analysis. (The internet has spurred a fair amount of such collaboration in math, physics, and even biology these days; in ornithology though, maybe not-so-much.)
Apart from the IBWO debate though, I'm certainly grateful for Cornell's eventual public release of this incredible ornithological relic and the story that goes along with it. For all birders it is a treasure!!
Maybe they'll even release a final summary of the IBWO search as promised before year's end, and in time for this winter's searchers to make use of it....
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