SCOTT SHALAWAY Bird-watchers gather flocks of data for survey

If you enjoy comparing notes with backyard birders from other parts of the country, the results of last winter's Project FeederWatch, just published in the Cornell Lab of Ornithology's newsletter, Birdscope, make fascinating reading. Chickadee and house finch numbers reached 15-year lows, while numbers of cardinals, red-bellied woodpeckers and sharp-shinned and Cooper's hawks were at all-time highs.
Project FeederWatch is an annual, continental survey of the birds that visit backyard feeders. By recording the birds that visit their feeders just twice a month from November through March, an army of dedicated bird-watchers helps Cornell ornithologists keep track of the population trends of backyard birds. Last year, more than 16,000 FeederWatchers submitted 92,353 checklists reporting more than 5.3 million birds. Thanks to that effort, ornithologists are slowly gaining a better understanding of the dynamics of backyard bird populations.
Since I first promoted Project FeederWatch in 1993, many readers have signed up, and based on their letters and phone calls, most enjoy it immensely. It forces them to set aside a few hours each month to enjoy their backyard birds. Many parents and grandparents add that it's a great way to spend time with the kids and cultivate a common interest. And it's great for introducing science to children and giving them a chance to collect meaningful data. Someday a new generation of biologists will credit Project FeederWatch with whetting their appetite for science.
Documentation
With an army of avid FeederWatchers, documenting population trends is easier than explaining them. David Bonter, FeederWatch's project leader, says that although outbreaks of West Nile virus (WNV) may explain plunging crow populations in the Midwest, little is known about how WNV affects chickadees and most other birds. Bonter finds it interesting that chickadee numbers took a dive not only in states with WNV outbreaks, but also in many other areas across the continent. This suggests that factors other than WNV may explain the widespread chickadee declines. Bonter sees this as good news for chickadee lovers because at lower populations chickadees compete less for food, and the surviving birds should theoretically thrive.
House finch numbers remain low because of the spread of a bacterial infection that can cause blindness and death. Fortunately, this disease seems to be density-dependent -- as finch numbers decline, the disease spreads more slowly. So fewer house finches are better for the population.
Growing populations of cardinals, red-bellied woodpeckers and sharp-shinned and Coopers hawks also bode well for other smaller birds. Their success implies than WNV doesn't affect other birds as severely as it does crows, which invariably die when infected with WNV. And because sharpies and Cooper's hawks dine almost exclusively on small birds, their success suggests that their food base is doing well, too.
Low participation
Despite the success of Project FeederWatch, relatively few birders participate. A just-published report by the U.S. Fish and Wildlife Service entitled "Birding in the United States: A Demographic and Economic Analysis" quantifies just how popular birding has become, and the numbers underscore how few are FeederWatchers.
The report defines birders as anyone 16 years of age or older who has either taken a trip of at least one mile from home for the primary purpose of observing birds, and/or those who observed or tried to identify birds around the home. According to this definition, 46 million Americans age 16 and older qualified as birders in 2001; that's 22 percent of the U.S. population. Most of those, 88 percent, are backyard birders. They spent $2.2 billion (that's billion with a & quot;b & quot;) on bird food; $628 million on feeders, nest boxes and baths; and $471 million on binoculars and spotting scopes.
So why do only 16,000 birders participate in project FeederWatch? That's a good question; I wish I had an answer.
To enroll in Project FeederWatch this year and join a proven citizen science project, send a check for $15 to cover administrative costs and a subscription to the quarterly newsletter BirdScope to Project FeederWatch, Department TWS, P.O. Box 10, Ithaca, N.Y. 14851 or call (800) 843-BIRD.
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