The Eastern Bluebird is a species familiar to millions in eastern North America, though they are nowhere near as common as they used to be. While they are still around and are seen when people build nest boxes, scientists wonder why there aren’t more.
Males are easy to recognize, with a bright blue back, head, and wings, and a rust-colored throat and breast. Females are similar, but much duller in color. These birds are cavity-dwellers, so they nest in natural tree cavities, old woodpecker holes and bird boxes. Nests are built with grasses and weed stems.
Young bluebirds are grayish in color. They have speckled breasts and their wings have blue tips. As they become adults, the blue color becomes much more obvious, and their speckles disappear.
This beautiful bird is a favorite of many people and is eagerly awaited in the spring after a long winter. Though if the weather is mild, they may stick around all year. They are considered are “partially migratory;” they fly south when food becomes scarce or when temperatures and other environmental conditions become harsh.
Eastern bluebirds eat a variety of foods depending on the season. In summer months they consume mostly insects. During the fall and winter seasons, when insects are less common, they eat fruits and plants.
The future of Eastern Bluebirds has been of concern to conservation agencies. Populations have shrunk over the last few decades (in some places by as much as 90%).
Two reasons why bluebird populations have declined are habitat destruction and competition. Much of their habitat has been turned into farmland or commercial property. Eastern bluebirds also have to compete with the more aggressive, introduced species, like House Sparrows and European Starlings, for food and nesting sites.