Invasive vs. Native Bird Species

Cornell’s Birdhouse Network Seeks Bird Enthusiasts to Help Monitor the Impact of Invasive Bird Species

In the mid-1800s, little brown birds called 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. Their surging populations have resulted in fierce competition with native birds for nesting sites.

According to 2003 data collected by The Birdhouse Network (TBN), a citizen-science project of the Cornell Lab of Ornithology, 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 enthusiasts discourage nesting by House Sparrows, the birds still comprise 10 percent of all reported nesting attempts when at least one egg is laid.