These are one of the relatively few thrush groups to be restricted to the New World. 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 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 lure 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.
Individuals wishing to build and mount nesting boxes for bluebirds should place predator baffles at least 36" in length on poles to prevent predation of young by snakes, cats and raccoons. Also, birdhouses should be placed at least several hundred yards apart, avoiding overhanging limbs which might provide springboards for predators. Non-native bird species competing with American bluebirds for nesting locations include the Common Starling and House Sparrow, both of which have been known to kill young bluebirds.
Bluebirds are attracted to platform bird feeders, filled with grubs of the darkling beetle - sold by many online bird product wholesalers as "mealworms." Some bluebird enthusiasts report the birds will eat raisins soaked in water as well. In addition, in winter many birders report bluebirds frequenting backyard heated birdbaths.
Bluebird numbers declined by estimates ranging to 70% in the 1970s due to a decline in habitat. However, in late 2005 Cornell University's Lab of Ornithology reported bluebird sightings at many locations in the southern U.S. as part of its yearly Backyard Bird Count, a strong indication of the bluebird's return to the region.
Species:
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Eastern Bluebird, Sialia sialis
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Western Bluebird, Sialia mexicana
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Mountain Bluebird, Sialia currucoides