FeederWatch Data Yield Insight into
Last Winter’s “No Birds” Scare 
and document dramatic montane irruption
in western mountains

Media contact: Allison Wells
607/254-2475, amw25@cornell.edu
Photos available to the media upon request.

     Autumn 2001, Ithaca, New York – 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. Recent findings from the Lab’s Project FeederWatch not only yielded insight into what was going on in the Northeast but also documented a dramatic irruption of montane birds in the West. 

     Many people in the northeastern United States and Canada expressed concern about low numbers—in some cases, a total absence—of Black-capped Chickadees, American Tree Sparrows, and other familiar feeder birds. They wanted to know, were these anomalies or had feeder bird populations declined?

     To find answers, researchers at Cornell Lab of Ornithology turned to data reported by participants in Project FeederWatch, the Lab’s citizen-science project 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 some 100 bird species that regularly visit feeders.

     “We analyzed last winter’s FeederWatch data for four common northeastern feeder birds—Black-capped Chickadee, American Tree Sparrow, White-throated Sparrow, and Dark-eyed Junco,” explains Wesley Hochachka, assistant director of the Cornell Lab’s Bird Population Studies program. “We found that numbers of Black-capped Chickadees and American Tree Sparrows were indeed lower in parts of the Northeast, particularly in November and December. However, chickadee numbers returned to near-normal levels by mid-winter.” This suggests that the chickadees had probably 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 do 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 Sparrow and Dark-eyed Junco.

     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, Internet-based birding listservs were reporting invasions of Stellar’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.

     “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 Laura Kammermeier, project leader for Project FeederWatch. “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 Project 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 to clearly document the irruptive patterns and movements of the Common Redpoll.

     Most recently, FeederWatchers are helping track the spread of mycoplasmal conjunctivitis, often referred to as House Finch eye disease because it primarily affects House Finches. It is manifested by symptoms including swollen, crusty eyes, which frequently lead to blindness and eventually death as the birds are caught by predators or eventually starve. Findings from this study appeared last year in the prestigious 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.

     Kammermeier and Hochachka invite everyone interested in birds to participate in Project FeederWatch. “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.”

     Each fall, there is great suspense among FeederWatchers to see which birds make the “FeederWatch Top-10 List,” the 10 most frequently reported species in North America. This year’s list reads: 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, and the species most frequently reported by FeederWatchers is 1) Dark-eyed Junco, seen at 85 percent of FeederWatch feeders.

     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://www.birds.cornell.edu/pfw>. Teachers are invited to inquire about Classroom FeederWatch.