Sialia sialis

Male has blue upperparts, red-orange throat, breast, and flanks, and white lower belly and undertail coverts. Female has blue-gray upperparts, a gray-brown wash across the back, sometimes a vague white eye-ring; the wings and tail are dull blue; and the underparts are paler orange than on male. Both sexes have a short, stout, black bill. Birds in winter are generally duller and more grayish. Juveniles are browner than are adults, with white streaking above and dusky spotting below, and have a white eye-ring. Length is around 7 inches (18 cm).

See Kaufman (1992, Am. Birds 46:159-162) for detailed information on identification of bluebirds.

Habitat includes forest edge, open woodland, and partly open situations with scattered trees, from coniferous or deciduous forest to riparian woodland, also pine woodland or savanna in the tropics. Nests are in natural cavities, old woodpecker holes, bird boxes, or similar sites, mostly 3-20 feet (1-6 meters) above ground.

Nesting period varies with location and may begin as early as late February in some areas and extends into late summer. Clutch size is usually 4-5. Individual females in most areas produce 2 broods/year, sometimes 3, very rarely 4. Incubation, mainly by the female, lasts 12-16 days. Young are tended by both parents, leave nest at 15-20 days. Male tends fledged young if female renests. Young of the first brood may help feed the second brood.

Males and females of nesting pairs of eastern bluebirds commonly engage in copulations with other eastern bluebirds. As a result, some nests contain nestlings with different fathers.