The most important step we can take to help bring back the bluebird is to provide nesting sites by setting out a bluebird box or starting a bluebird trail.
Bluebirds are territorial, prefer open grassland with scattered trees and are cavity nesters (similar to many species of woodpecker). Bluebirds can typically produce between two to four broods during the spring and summer (March through August in the Northeastern United States). Males look for potential nest sites and try to attract prospective females to those nesting sites with special and in treating behaviors to watch that include singing and flapping their wings, and then placing some material in a nesting box or cavity. If the female likes the male and the nesting site, she alone builds the nest and incubates the eggs. Below are artificial cavities (bird houses) that will also attract bluebirds and help increase these beautiful vibrant "blue" birds population on the planet. Help Bluebirds make the planet more colorful by putting up a bluebird house and giving them another place to nest.
Bluebird Bird House Dimensions for making your own Bluebird House