A few eastern bluebirds attempt to winter-over in Minnesota, but nearly all of them spend the cold months in states south of us, returning in greatest numbers between mid-March and mid-April.
Bluebird habitat includes farmlands, orchards, roadsides and open woodlands. They nest in natural tree cavities, old woodpecker holes, wooden fence posts, and man-made boxes. Insects are the core of their diet, but they also eat fruits and seeds when insects are scarce.
The male bluebird has a sky-blue head, back and tail, a rusty-red throat and breast, and a white belly. The female is a fainter version of the male.
The 7-inch bird was nearly eliminated in Minnesota a half-century ago because of the increased insecticide use, fewer wooden fence posts, and a competition for nest sites from two introduced species — the house sparrow and the European starling.
Numerous individuals and organizations have helped bluebirds make a remarkable comeback by establishing and maintaining trails of nesting boxes. Such work seems to be the bird's best hope for survival. The trail consists of five or more pairs of nesting boxes set out by late March in their habitat.
To learn more, check out the Bluebird Recovery Program of Minnesota (bbrp.org).
Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.
