About Bluebird Houses

The bluebird population in the United States was decreasing rapidly until the advent of bluebird houses. These small nesting boxes aided the bluebird in re-establishing itself throughout its range. Bluebird houses need to be built so they will attract bluebirds to live in them, and to deter other less desirable species and bluebird predators from gaining access to them.

  1. Declining numbers

    • There are three main species of bluebirds in the U.S.: eastern bluebird, western bluebird and mountain bluebird. The eastern bluebird was most affected by a number of factors, and its numbers fell drastically through the 1950s and 1960s. The common usage of pesticides killed off much of their preferred food--insects--and caused many bluebird deaths from birds consuming bugs exposed to pesticides. Species of birds such as the house sparrow and European starling compete for the bluebird's favorite kind of nesting site, a cavity in a tree, and also have been known to kill the young bluebirds and even the adults to claim a nest. Add those scenarios to severe winters and loss of habitat, and the eastern bluebird was becoming endangered.

    Bluebird house design

    • The ideal bluebird house will be constructed so that the roof will provide shade and keep rain from entering the box. It should not have a perch by the entrance hole--bluebirds don't need one--but starlings and house sparrows prefer one and would gladly take advantage of it to stake a claim on the box. The entrance hole itself should be no larger than 1 9/16 inches across for the western and mountain species and even smaller for the eastern bluebird. This allows them in but makes it difficult for larger birds to enter. There should be some ventilation, but not enough that it can become very cold or wet in the nest box. Holes to allow drainage in the floor and a door that opens so that the nest box can be cleaned and checked for other species is a good idea as well.

    Location

    • Bluebird houses should never be simply mounted on a tree or a fence; this allows easy access for predators such as snakes, raccoons and cats. Bluebird houses should be mounted on a galvanized pipe with the entrance hole about 5 feet off the ground. Bluebirds tend to like open grasslands such as meadows, orchards and roadsides in the country. Cemeteries, golf courses, parks and very large lawns away from buildings are excellent locations for a bluebird house.

    Considerations

    • A bluebird house should be set up so that it is facing open spaces, but away from prevailing winds if possible. There should be a tree, telephone pole and wires, or some other perch that the bluebird can utilize within no more than 100 feet from the house. Bluebird houses should not be installed right next to each other, as bluebirds like to establish their own territory. Placing them at least 100 yards apart allows them to do this. They should never be put where pesticides are commonly employed, as this will reduce their food supply and put them in danger of being poisoned themselves.

    North American Bluebird Society

    • The North American Bluebird Society was established in 1978 to help bring back the bluebird population. It consists of thousands of volunteers who put up bluebird houses to help the species make a comeback. This organization has very specific specifications for bluebird houses to ensure the best chance of bluebirds living in them and raising a family. For example, the North American Bluebird Society does not want a birdhouse to be built from pressure-treated wood, which can contain toxic compounds. NABS has a website that approves bluebird houses and allows data to be entered regarding bluebird populations by those who put up houses.