Bluebirds are one of the most loved and recognized of all birds, and their cheerful song is welcomed by most birders. In the mid 20th century, bluebird populations fell dramatically due to habitat loss and competition for nesting sites with house sparrows and European starlings. One way to help increase the bluebird population is by beginning a bluebird trail.
Bluebird nest boxes are most successful when placed on a post or pole, in an open area, about 4' to 5' high. For Eastern bluebirds, a 1.5" diameter entrance hole is needed, while the Western and Mountain bluebirds prefer a slightly larger 1.5625" diameter entrance hole. A rough interior aids the birds in exiting the nest, and all houses should include drainage on the base and protection from water entering the unit. A bluebird house should never have a perch, as they do not need one and it prevents predators from overtaking the nest.