As Winters Grow Warmer, Cornell Ornithologists Recruit 15,000 Birdwatchers To Document Avian Whereabouts

These volunteer "citizen scientists" are participating in Project FeederWatch, a winter-long (November through April) survey of birds that visit feeders throughout the United States and Canada. The survey is sponsored by the Lab of Ornithology at Cornell University, in partnership with Bird Studies Canada, National Audubon and the Canadian Nature Federation. Started in 1987, the project has grown to more than 15,000 participants.

FeederWatchers in 1999-2000 reported an increase in "irruptive" species (birds that typically spend the winter in the north but periodically "irrupt" into more southerly regions, probably in response to low food availability farther north) east of the Rockies. For example: o Common redpolls appeared in larger-than-average numbers even for an irruption year--larger than in any winter since 1994. They were especially abundant in a band stretching from the Northern Rockies to the North Atlantic region.

o Northern shrikes invaded feeding stations across the northern tier last winter. Nicknamed "butcher birds" for their technique of impaling their prey on thorns and branches, shrikes showed up at many feeding stations to catch songbirds, presumably because of lower numbers of small rodents in the fields where they typically hunt.

o Last winter's FeederWatch data also indicated a scarcity in ground-feeding birds such as Harris's sparrows. The lower abundances were especially notable in the mid- and south-central regions, possibly related to drought. Most ground-feeding species rely on seeds produced by smaller plants (grasses and forbs), and production of these seeds can be easily affected by rainfall--or a lack of it.

o Based on long-term data from FeederWatchers, a paper published in the Canadian Journal of Zoology documented for the first time the cyclical changes in varied thrush abundance. FeederWatch data revealed that, on average, this species peaks in abundance every second year, perhaps in response to acorn availability in winter.

o Another discovery appeared in The Condor, a scientific journal published by the Cooper Ornithological Society. The data showed that although the common redpoll is an irruptive migrant probably forced south by lack of food, the redpolls' movements are like those of any other winter migrant when the birds irrupt southward. Findings such as these help scientists better understand the lives of bird species that would otherwise be a mystery because they live far to the north, in regions not typically covered by other monitoring programs.

FeederWatchers also play a critical role in tracking outbreaks of avian diseases. In 1994, Cornell Lab researchers asked FeederWatchers to help track the spread of a disease previously almost unknown in wild birds. This disease, called mycoplasmal conjunctivitis (often referred to as house finch eye disease because it primarily affects that species) results in swollen, crusty eyes, frequently followed by blindness and death as the birds are caught by predators or eventually starve. Writing in the journal Proceedings of the National Academy of Sciences, Cornell ornithologists explained how an infectious disease might become the main factor regulating the abundance wild animals such as finches. Starting this winter, researchers are asking FeederWatchers to help with the House Finch Disease Survey, now newly expanded, to learn whether the disease has crossed the Great Plains and started to infect house finches in western North America. "FeederWatchers are the eyes and ears for scientists studying North American feeder bird populations," says Wesley Hochachka, assistant director of the Cornell Lab's Bird Population Studies program and a co-author of many FeederWatch-related scientific papers. "There's simply no other way to acquire data about continentwide populations throughout the entire winter. These data are critical in helping us understand both long- and short-term changes in bird populations and their environments."

A nominal fee of $15 is requested to help cover costs of data processing as well as the posters, newsletters and other materials FeederWatchers receive. Volunteer citizen-scientists can sign up for Project FeederWatch by calling the Cornell Lab of Ornithology at 800/843--2473 in the United States (in Canada, call Bird Studies Canada at 888/448-2473) or by visiting the web site: http://birds.cornell.edu/pfw/ Volunteers also can sign up by mailing a check to "Cornell Lab of Ornithology" at this address: PFW/Cornell Lab of Ornithology, P.O. Box 11 Ithaca, NY 14850.