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IVORY-BILLS  LiVE???!  ...

=> THE blog devoted to news and commentary on the most iconic bird in American ornithology, the Ivory-billed Woodpecker (IBWO)... and... sometimes other schtuff.

Web ivorybills.blogspot.com

"....The truth is out there."

-- Dr. Jerome Jackson, 2002 (... & Agent Fox Mulder)

“There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.”

-- Hamlet

"All truth passes through 3 stages: First it is ridiculed. Second, it is violently opposed. Third, it is accepted as self-evident."

-- Arthur Schopenhauer

Sunday, October 30, 2011


-- Flight of the Imperial --


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:


The more academic article from "The Auk" here:


They have also put the film clip footage up on YouTube:


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....

Sunday, October 16, 2011


-- Miscellany --


Mark Michaels, over at IBWO Researchers' Forum pointed out the below article which briefly mentions that Cuba’s leading ornithologist, Orlando Garrido believes the "Cuban Ivory-billed Woodpecker still lives in remote regions of eastern Cuba":

[sorry, article appears to no longer be available except via membership]

Meanwhile, in the fun-and-games-with-statistics dept. no less than "The Economist" magazine makes mention of the two recent statistical studies that essentially declare the Ivory-bill extinct (although statistics can't easily or sufficiently be applied to this situation).


And, a nice result for one University of Kentucky professor, whose passion for the Ivory-bill story won him a teaching award from the National Association of Biology Teachers:


Lastly, for a trip down memory lane, this press release from 6+ years ago when the whole controversy was blossoming:


The leaves will be off the trees soon, and prime IBWO search conditions prevail again, but no idea how many searchers will spend any significant amount of time in the field this season....

Saturday, October 01, 2011


-- On Proving a Negative --


In a comment on the previous post, "Steve" essentially asks WHAT will it take for some of us to conclude that the Ivory-bill is no more? I was going to respond in the comments (and now Jacob has) but it deserves a separate (more long-winded) post, since it's such a common question:

The basic answer is pretty simple... you send capable folks out to areas that a species might conceivably remain in (or actually have been sighted) and do a reasonably thorough, organized search... AND come up empty-handed... NO credible sightings, nor signs of the bird's presence. THAT would be indicative of possible extinction. You can't prove extinction; you can only keep amassing more and more data toward its support.

If such searches were conducted for the Dodo, or Moa, or even Passenger Pigeon, most likely there would be nothing to show for it. But in the case of the Ivory-bill almost every such large scale search results in (even if skeptics don't acknowledge it) a few sightings claims from credentialed, credible individuals, and additional possible signs of the bird (foraging signs, cavities, auditory encounters) -- if there were sightings with NO such other evidence, it would be more difficult to take the sightings seriously... OR, if there were signs, but without ever any sightings, the signs could be easily written off; but the fact that both types of evidence occur on rare, yet repeated occasions, makes it more difficult to simply ad hoc (because it fits a preconceived hypothesis), label them all 'mistakes' and misidentifications. Indeed, as I've argued previously, if mistakes are this easy and prevalent in birding then doing bird counts and censuses must be a futile waste of time, they would be so heavily flawed in regards to look-alike birds (and the majority of birds have look-alikes). [Indeed, many argue that the actual raw data of bird counts is hugely erroneous (both unreliable and invalid), and the only real worth derives from looking at relative trend figures over extended periods of time.]

Nor does it matter if there are 5000 other individuals with little credibility or experience who erroneously report IBWOs; you can't automatically generalize from such known instances to all cases, but must view each case individually on its own merits (or lack thereof).

Yes, it is hugely troublesome that these unconfirmed claims have been going on for 60+ years without verification or better photographic evidence. And frustrating too that claims still come from widely disparate areas -- almost certainly there can't be that many separate populations of IBWO left. I understand why the likes of Paul Sykes, Jerry Jackson, and others have largely given up hope that such claims make much sense any longer, no matter how credible or certain any given observer. When every followup seems to fail to definitively confirm the birds once-and-for-all, it is easy to conclude that a telling pattern is evident.

I continually have to ask though, if a bird is truly incredibly rare, possibly even hanging on by a thread, residing in remote, difficult habitat (not well-frequented by birders), living principally high up in tree canopies and within cavities, possibly wary of humans, and capable of rapid long-distance flight... then what would the evidence, if any, for its existence look like -- and maybe, perhaps, just possibly, it might look very similar to that which we have before us. The best explanatory fit and best odds for the entire panoply of evidence at hand may still be that a few Ivory-bills swoop and kent and double-knock somewhere in a dense quarter of the American Southeast.
...Or, not. The limits of my own patience do creep closer with each passing year.

And here's the story of another bird species (the Jerdon’s Courser) that relates somewhat to this whole discussion:

http://www.downtoearth.org.in/content/lives-others?page=0,3 ------------------------------------------------------------------------

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