Ivory-billed debate

 

What is the Ivory-billed Woodpecker debate about?


On one level, this debate is about science—how we know something, how we convey that knowledge accurately to others, and how we effect public policy given what we know. On a more basic level, this debate highlights the importance of bird identification, what constitutes valid documentation in ornithology, and how that is reflected in the historical record.


The current debate stems from a report published in Science magazine asserting that at least one Ivory-billed Woodpecker existed as recently as 2004 (1). The evidence supporting that claim is weak and inconclusive.


A brief, blurry video said to provide conclusive proof

No evidence confirms the alleged rediscovery of the Ivory-billed Woodpecker

instead shows a bird that almost certainly is a Pileated Woodpecker. As demonstrated by painstaking analyses, we know the bird cannot be an Ivory-billed Woodpecker because several features rule out that species but not Pileated (2, 3, 4). Faint and ambiguous sound evidence said to be suggestive of Ivory-billed drum signals and vocalizations is simply inconclusive (5). Moreover, many of the sounds derive from other sources (4, 6). Several reported sightings, mostly brief glimpses by lone observers, cannot be verified independently. We simply cannot know what the observers actually saw.


In sum, no evidence confirms the alleged rediscovery of the Ivory-billed Woodpecker. Indeed, confidence in the claim has eroded with failure to verify its existence despite massive searches. Confidence in scientific claims grows when evidence is critically evaluated and independently verified. A critical issue in this debate, then, is the accuracy of claims and the public expectations based on labels attached to those claims—in this case, neither “confirmed” nor “conclusive” are accurate.


What is the debate not about?

“The very nature of our brains—evolved to guess the most plausible interpretation of the limited evidence available—makes it almost inevitable that, without the discipline of scientific research, we shall often jump to the wrong conclusions”

—Francis Crick


The burden of proof lies with those that claim rediscovery. That does not mean the Ivory-billed Woodpecker is extinct; it means that we lack indisputable evidence for its continued existence.


Strong opinions have obscured the obvious: that this debate is not about whether one is for or against conservation and protecting old-growth forests. Could a small population of Ivory-billed Woodpeckers exist? Was the last individual a bird in Arkansas? The answer to these questions is unknown. Common sense and critical reasoning suggest the answer is no. Prevailing ideas about populations suggest that for even one bird to be alive in the past few years, the number of birds that must have existed to produce that survivor would have to have been large enough that they would not have remained unknown over the past 60 years. Even so, how do we protect something that cannot be found?




What is at stake?


At stake is the credibility of observational evidence and the most effective way to protect threatened species. Increasingly hard choices have to be made in conservation: what species to protect and what strategies will achieve the greatest overall return. Because public and private entities have expended considerable resources in time and money, this controversy highlights the urgent need for impartial, evidence-based decision-making in bird conservation (7). Shouldn’t accurate scientific evidence drive these decisions?



Is there hope?


“When people learn no tools of judgement and merely follow their hopes, the seeds of political manipulation are sown.”

—Stephen Jay Gould

The idea that the Ivory-billed Woodpecker “persists” was said to be a “ray of hope” (8)—hope that extinction might be averted and that redemption for our shameful treatment of the species was at hand. Stubborn attachment to this hope bears great risk, however. It forestalls facing reality and delays the resolve needed to make sound judgments for the thousands of species that remain threatened worldwide, some requiring relatively small sums to protect (9). Postponing action to protect these species and habitats while public policy remains mired by those following their hopes, risks more species edging closer to the Ivory-billed’s fate. Is that right and who is in the best position to judge?

An ironic example is the relative lack of attention given to the Imperial Woodpecker, the largest woodpecker in the world and a close relative of the Ivory-billed (10). Imperial Woodpeckers depended on old-growth pine forest in montane western Mexico. Those forests are far more threatened than old-growth bottomland forests in the southeastern United States. Recent reports of Imperial Woodpeckers, albeit just as uncertain as the current spate of Ivory-billed sightings, have been met with relative silence by the same proponents of the Ivory-billed “rediscovery”. No photographs of living Imperial Woodpeckers have yet been published. Would discovery of such images in the past few years be enough to inspire and motivate protection of these forests? Mexican ornithologists might think so. Could the past two years have been the critical remaining time? We will never know.







Imperial Woodpeckers

J. L. Ridgway in Nelson 1898. The Auk 15: 217.



What is this website about?


These pages amplify on analysis of a bird incidentally videotaped in Arkansas by David Luneau. I have carefully reviewed the original materials and attempted to replicate the Arkansas video with releases of Pileated Woodpeckers. Other evidence and aspects of the debate, for example reports from Florida and elsewhere, may be discussed in the future. I will edit and change these pages from time to time to correct errors and clarify or respond to issues.



Imperial Woodpeckers

R. M. Mengel in Tanner 1968. The Auk 81: 75.


Louis Bevier — 5 July 2007 (last updated 14 August 2007)

 

Ivory-billed Woodpecker, left. Art by David A. Sibley