For the Birds Radio Program: Discouraging House Sparrows in Nest Boxes
Laura gives some concrete strategies for discouraging House Sparrows from using nest boxes. (3:42)
In very urban areas where few naturally occurring species live, house sparrows may be welcome visitors, but where small native songbirds abound, “English sparrows” really are serious pests. Carrol Henderson, director of the DNR Nongame Wildlife Program, writes in his excellent book, Woodworking for Wildlife, “There is no such thing as peaceful coexistence between house sparrows and bluebirds, chickadees, tree swallows, or house wrens. If house sparrows are successful in catching a female songbird in a nest box with its young, they will kill the whole family by pecking their skulls open.”
House sparrows are not native to America, and so are not protected by the Migratory Bird Treaty Act or other laws protecting native birds. It is perfectly legal to make pets of them, or to toss out eggs or even kill nestling or adult house sparrows. To discourage them without resorting to killing them, don’t put bread or cheap seed mixtures in suburban or country bird feeders–house sparrows don’t particularly like sunflower seeds or suet.
You may want to keep nest boxes closed until bluebirds and swallows return in late March or April–by then, most house sparrows will already have established their nests. Once you open the boxes, check them frequently, tossing out any nest materials brought in by sparrows–you can usually recognize their nests by the trash incorporated into it.
Bluebird and swallow boxes should have a hole no bigger than 1 1/2-inches in diameter to keep European starlings out but, because house sparrows are small, a hole big enough to allow bluebirds in also accommodates sparrows.
In the directions for building one bluebird box, Carrol Henderson says, “Some people feel that sparrow use…can be diminished by cutting a 3-inch-diameter hole in the roof and covering the hole with 1/4 or 1/2-inch hardware cloth mesh. Bluebirds don’t seem to mind the ‘sunroof but sparrows may be discouraged by it. Such open top nests need to be covered in March and April to avoid mortality during spring ice storms.”
Although it is sensible and environmentally sound to discourage House Sparrows from natural settings where they can harm naturally-occurring birds, there’s an element of irony in despising a species that shares so many of our own qualities–a bird that has associated itself with humans since the earliest civilizations sprung out of Africa–a bird that shares our love for central heating, garish city lights, and fast food. I suspect that as long as humans survive on the planet, House Sparrows will be at our side, their comfortable cheeping accompanying the sounds of horns and sirens. A world that is inhospitable to sparrows may be a world that cannot support humans, either.