The bluebirds are medium-sized, mostly insectivorous or omnivorous birds of the thrush family. These are one of the relatively few thrush genera to be restricted to the Americas. These are attractive birds with blue, or blue and red, plumage. Female birds are less brightly colored than males, although color patterns are similar and there is no noticeable difference in size between genders.
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 northeast). Males identify potential nest sites and try to attract prospective female mates to those nesting sites with special behaviors that include singing and flapping wings, and then placing some material in a nesting box or cavity. If the female accepts the male and the nesting site she and she alone builds the nest and incubates the eggs.
Bluebirds are attracted to platform bird feeders, filled with grubs of the darkling beetle, sold by many online bird product wholesalers as mealworms. Bluebirds will also eat raisins soaked in water. In addition, in winter bluebirds use backyard heated birdbaths.
Information source: Wikipedia