ITHACA, N.Y. -- The birds could fly, but they couldn't hide for long from the thousands of volunteer bird-watchers throughout North America who reported their observations to the Cornell Laboratory of Ornithology-based citizen-science program, Project FeederWatch. Now, having solved the 2000-2001 mystery of missing birds in the Northeast and misplaced birds in the West, FeederWatchers are preparing for whatever the upcoming season brings.

Project FeederWatch 2000-01

Top 10 Birds of North America*
10) Black-capped chickadee
9) House sparrow
8) European starling
7) Northern cardinal
6) Blue jay
5) American goldfinch
4) House finch
3) Downy woodpecker
2) Mourning dove
1) Dark-eyed junco

*Regional Top 25 lists are at

http://birds.cornell.edu/pfw/DataRetrieval/Top25/Top25.htm

"Last fall and early winter, the Cornell Lab of Ornithology was inundated with phone calls and e-mails from bird enthusiasts concerned about a lack of birds at their feeders and around their yards," says Wesley Hochachka, assistant director of the Cornell lab's Bird Population Studies program. "When we analyzed reports from Project FeederWatch, they not only yielded insight into what was going on in the Northeast but also documented a dramatic irruption of montane birds in the West," he said, referring to birds that normally dwell at higher elevations.

The concern in the northeastern United States and Canada was about early-winter low numbers -- in some cases, a total absence -- of black-capped chickadees, American tree sparrows and other familiar feeder birds, Hochachka recalls. "People were worried. They wanted to know, were these anomalies or had feeder-bird populations declined?"

To find answers, researchers at the Cornell Lab of Ornithology turned to data reported by participants in Project FeederWatch, in which bird enthusiasts throughout North America count the numbers and kinds of birds that visit their feeders from November through early April. Data are combined by lab researchers to determine population distribution and abundance of some100 bird species that regularly visit feeders.

"Our analyses found that numbers of black-capped chickadees and American tree sparrows were indeed lower in parts of the Northeast, particularly in November and December of 2000," Hochachka says. "However, chickadee numbers returned to near-normal levels by mid-winter 2001. This suggests that the chickadees probably had been present in those areas early on but had not been visiting feeders, perhaps because they had found ample food in their natural habitats."

As for the tree sparrows, Hochachka notes that they seemed to have shifted their winter whereabouts to the area around western Lake Erie. In short, FeederWatch data did not indicate a general decline in abundance, but rather suggest that the birds probably shifted their wintering ranges compared to previous years. The same is likely true for white-throated sparrows and dark-eyed juncoes.

More dramatic than the early paucity of chickadees in the Northeast was the impressive dispersal of several montane species from the Western mountains. Before the FeederWatch season even began in mid-November, birding e-mail listservs were reporting invasions of Steller's and pinyon jays, Clark's nutcracker, red-breasted nuthatch, dark-eyed junco and Cassin's finch. These species were vacating their mountain homes for lower elevations on the Pacific coast, the Great Plains and lower elevations of southern Arizona.

Back in Ithaca, Laura Kammermeier, project leader for FeederWatch, was ready: "Each year, we expect FeederWatch to document the waxing and waning of relatively predictable irruptions of winter finches -- typically, species such as common redpoll and evening grosbeak irrupt biennially from boreal Canada and the extreme northern U.S. into regions farther south," says Kammermeier. "We were excited that FeederWatchers were able to capture this unexpected, large-scale montane dispersal." Hochachka and Kammermeier believe that the dispersal is related to a scarcity of food, a result of low precipitation that also resulted in severe forest fires and low river levels in much of the West. The birds likely moved into areas where food was more abundant.

Findings from FeederWatch help researchers understand changes in North American feeder bird populations not only during a particular winter but also over many years. FeederWatch was the first study to document cyclical changes in varied thrush abundance. It also was the first clearly to document the irruptive patterns and movements of the common redpoll.

Most recently, FeederWatchers have been helping track the spread of mycoplasmal conjunctivitis, often referred to as house finch eye disease because it primarily affects that species. (Disease symptoms include swollen, crusty eyes, which frequently lead to blindness and eventually death as the birds are caught by predators or eventually starve.) Findings from the conjunctivitis survey were reported in the journal, Proceedings of the National Academy of Sciences. " The assistance of FeederWatchers with the House Finch Disease Survey is as important as ever, as lab researchers try to understand why this disease spread so rapidly and why it persists in eastern North America," says Andre Dhondt, the Morgens Professor in the Lab of Ornithology and author of the journal report.

The Cornell ornithologists invite everyone interested in birds to participate in Project FeederWatch during the 2001-02 season. "To get a complete picture of what's happening with feeder birds across the continent, we need as many people as possible to become the eyes and ears of our scientists," says Kammermeier.

Participants receive a research kit that includes a full-color feeder bird poster and calendar, and the FeederWatcher's Handbook . They also receive summaries of FeederWatch data and other findings published in the lab's quarterly newsletter, Birdscope. A $15 fee helps cover the cost of materials and data analysis. People of all ages and skill levels are encouraged to participate. "FeederWatch is a wonderful family activity and is a great way for parents to demonstrate to their kids that their observations matter," Hochachka says.

For more information or to sign up, call the Cornell Lab of Ornithology at (800) 843-2473 (Canadians, contact Bird Studies Canada at (888) 448-2473) or visit the FeederWatch web site at http://birds.cornell.edu/pfw . Teachers are invited to inquire about Classroom FeederWatch.