There's nothing like 30 inches of heavy, sticky snow to concentrate a flock of birds at a bird feeder. I've seen more than a dozen different species at my backyard feeder since the storm hit. I like to think all that seed and suet is helping them survive a miserable winter, but is it true?
Apparently so. A study from Wisconsin a few years ago showed that black-capped chickadees are more likely to survive the winter if they have access to feeders. (Black-capped chickadees, in case you haven't heard, are the Perfect Bird.) But feeders don't make them soft and lazy: according to another study, birds that had access to feeders in the past are still perfectly able to feed themselves once the feeders are taken away.
Bird feeders are the focus of two ongoing citizen science projects: Project Feeder Watch and the Great Backyard Bird Count (this year's count will be held next weekend). The data from these counts, like the data from the 110-year-old Christmas Bird Count, are pretty noisy, but they're a reliable-enough way to monitor population trends.
One of the most dramatic examples of how bird feeders can affect birds' behavior comes from a study of European blackcaps. The birds usually fly to Spain or Portugal for the winter, but lately a subpopulation has been wintering in Great Britain, drawn by the abundance of bird feeders. Because birds that winter together tend to breed together, the species appears to be splitting in two, all because British bird lovers are generous with their bird seed.