The house sparrow, Passer domesticus, is one of the most familiar, widespread birds in the world. The problem is, house sparrows are also invasive birds that disrupt other bird species. Because they are not native birds in North America, it is permissible to use different methods to control house sparrow populations. Many birders investigate how to discourage house sparrows in order to attract a more diverse range of bird species in their backyard and to protect other species threatened by house sparrows’ aggression.
House Sparrow History
House sparrow are believed to be one of the oldest known birds. The house sparrow originated in the Mediterranean region and spread throughout Europe. The birds were imported to North America in the 1850s both for nostalgic reasons and to help control insect populations. By the time it was realized that house sparrows do not regularly eat insects outside the nesting season, the birds’ range had spread tremendously, despite belated eradication attempts. Today, there are an estimated 150 million house sparrows in North America alone, and the species is the most abundant songbird in the world.
Problems With House Sparrows
House sparrows can cause many problems for native birds, including:
- Competing for nesting sites, even killing adult birds, hatchlings and eggs
- Usurping food sources and reducing diversity at backyard feeders
- Crowding out less aggressive birds from traditional ranges
While all bird species may suffer somewhat from the invasion of house sparrows, species that are particularly vulnerable include:
- Eastern and western bluebirds
- Purple martins
- Tree and cliff swallows
These types of birds are often in direct competition with house sparrows for food sources and nesting sites, and house sparrows’ more aggressive behavior is often successful in displacing them.
Photo – Bluebird House © Roger H. Goun