In the mid-1800s, the little brown house sparrows were introduced into the United States from Europe to alleviate homesickness for the Old World and because they were believed to control insect pests. Since then, these adaptable birds have made themselves quite comfortable here -- spreading their wings across all of North America in vast numbers, according to TBN project leader Tina Phillips. She says surging populations of house sparrows have resulted in fierce competition with native birds for nesting sites. According to 2003 data collected by TBN, house sparrows account for 43 percent of all competitor species (species that take over nest boxes intended for native birds). And although most nest-box (or bird-house) enthusiasts discourage nesting by house sparrows, the birds still comprise 10 percent of all reported nesting attempts when at least one egg is laid.
What effect is this having on North America's bluebirds, swallows and other native cavity-nesting species? "We don't know," says Phillips. "There are no long-term studies showing the effect of competition between house sparrows and our native cavity-nesters. This is one reason why we're asking everyone across the continent to become part of our nest-box monitoring project. The only way to get answers is to get data, which are provided most effectively by people who monitor nest boxes."
TBN participants monitor activity inside nest boxes and keep track of data such as egg-laying dates, numbers of eggs and nestlings, and fledging dates. The participants send their observations to researchers at the Cornell Lab of Ornithology, where the data are combined with observations from across North America, to determine the annual nesting success of
Contact: Allison Wells
Cornell University News Service