What happens when a species becomes so rare that it can no longer be reliably found or studied, yet sightings are reported every few decades -- is the species extinct or merely lost to science? Ron Rohrbaugh, an extension associate at the Cornell Lab of Ornithology who leads the lab's research on the ivory-billed woodpecker, pondered this question Dec. 14, before about 50 members of the Cayuga Bird Club and other bird enthusiast at the Johnson Center for Birds and Biodiversity Visitors Center Auditorium.

If a species is prematurely dubbed extinct, significant consequences can ensue, he said; federal protection for the species and its habitat dries up, the public loses interest in the species and sightings might be disregarded.

Rohrbaugh used the ivory-billed woodpecker as an example of how difficult it is to detect and study a lost species, one that is so rare that it cannot be easily observed. When a species is assumed to be extinct before enough data have been collected to prove its extinction, Rohrbaugh said such a mistake is called the "Romeo Error." The ivory-billed woodpecker, he said, has been "lost, found, 'Romeo'ed,' found again, lost again and now at risk for being 'Romeo'ed' one last time."

By the 1920s, the ivory-billed woodpecker was considered a lost species, with no known population. In 1924, Arthur Allen, the founder of the Cornell Lab of Ornithology, captured on film two ivory-bills in Florida, leading many to believe the species had been rediscovered, Rohrbaugh said. The species was lost again until 1935, when Allen recorded the species on film in northeast Louisiana. The last official sighting was in 1944, and thereafter, the species was considered by many to be extinct.

Then, in 2004, the bird was reportedly sighted in eastern Arkansas and subsequently filmed and sighted seven more times. After the findings were published in the journal Science in 2005, many scientists believed that the bird had been rediscovered yet again.

This paper initiated an extensive search for the woodpecker, funded in large part by private donations and the federal government. The search included the use of GPS technology to track search efforts, automated sound recording units, remote surveillance cameras, and the development of a specialized ranking system to assess the quality of sightings.

The Arkansas search, which covered hundreds of thousands of acres of the woodpecker's bottomland hardwood forest habitat, was like trying to find the only remaining pileated woodpecker (a large woodpecker native to New York) in a completely forested area twice the size of Tompkins County, Rohrbaugh said.

Although the search has since been suspended, no definitive conclusions have been made. Such bird species as the Madagascar pochard (a species of duck) and the cherry-throated tanager have recently been observed after having not been seen in many decades.

"Long stretches of time can go between observations of some of these birds, when in fact, populations do exist," Rohrbaugh said.

The job of bird enthusiasts and conservation biologists, Rohrbaugh said, is to "make sure [critically endangered birds] don't slip into obscurity" and become lost or extinct.

Graduate student Kate Neafsey is a writer intern at the Cornell Chronicle.