The bluebirds are medium-sized, mostly insectivorous or omnivorous birds in the genus Sialia of the thrush family Turdidae.
Species include the Eastern Bluebird Sialia sialis, Western Bluebird, Sialia mexicana and the Mountain Bluebird Sialia currucoides.
As the name implies, 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 sexes.
Bluebirds are territorial, prefer open grassland with scattered trees and are cavity nesters. Predators of young bluebirds in the nests can include snakes, cats and raccoons. Non-native bird species competing with bluebirds for nesting locations include the Common Starling and House Sparrow, both of which kill adult bluebirds sitting on their nests along with the young and eggs in order to claim the nesting site.
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.
By the 1970s, bluebird numbers had declined by estimates ranging to 70% due to unsuccessful competition with house sparrows and starlings, both introduced species, for nesting cavities, coupled with a decline in habitat. However, in late 2005 Cornell University's Laboratory of Ornithology reported bluebird sightings at many locations in the southern United States as part of its yearly Backyard Bird Count, a strong indication of the bluebird's return to the region. This upsurge can largely be attributed to a movement of volunteers establishing and maintaining bluebird trails.
