from "Wild About Birds, The DNR Bird Feeding Guide"
Eastern Bluebirds have made a dramatic recovery throughout much of the Midwest. Thousands of people place and manage nest boxes for them in backyards, farms and meadows.
A male bluebird is a rich blue color with a rusty-red upper breast and a white belly. Females have similar but duller color patterns. Bluebirds are about two-thirds the size of robins.
Eastern bluebirds nest across most of the eastern half of the United States, the eastern Great Plains states of North Dakota to Texas, northern Mexico, and southern portions of the Canadian provinces from Saskatchewan eastward to the Atlantic Ocean.
Meadows, orchards, farms, cemeteries, golf courses, pastures, suburban and rural backyards and woodland edges will all make good habitats for bluebirds. In the fall bluebirds migrate to the southeastern states, Atlantic seaboard states and northern Mexico. A few bluebirds may winter in northern regions where adequate food and shelter is available.
Bluebirds return from southern wintering areas between late March and mid-April. They nest in natural cavities, rotted wooden fence post tops, old woodpecker holes and nest boxes. Usually their clutches consist of four or five light blue eggs, which hatch after 12 to 14 days of incubation. The young fledge after 19 days of parental care and feeding.
Most bluebirds attempt to renest and raise a second brood during the same season. Their second clutch of eggs is usually smaller:three to four eggs. Sometimes a bluebird will raise three broods in a summer.
The eastern bluebirds diet consists of 90 percent animal food in the summer and 60 percent in the winter. Bluebirds can survive on bittersweet berries during cold weather prior to the emergence of insects in the spring.
---1995 State of Minnesota, Department of Natural Resources. "Wild About Birds, The DNR Bird Feeding Guide", Carrol L. Henderson