How to … attract bluebirds with nesting boxes

A male eastern bluebird darts from its perch to the ground to capture an insect. When the light is angled just right, the feathers on the bird's back and tail flash a brilliant blue — so blue, in fact, the bird appears unreal. We stare in awe, mouths agape.

Three or four decades ago, the U.S. population of eastern bluebirds was in peril. Biologists estimate population of the colorful birds had dropped 90 percent. Reasons for the decline were the introduction of two European invasive bird species, the starling and the house sparrow. Both of these non-native species competed with bluebirds for nesting cavities. They were also known to peck holes in bluebird eggs and kill bluebird nestlings.

Modern farming also took its toll. Indiscriminate use of pesticides reduced the number of insects, the main diet of bluebirds. In addition, tree-lines and shelterbelts were cut to make room for row crops. These trees, along with the now outdated wooden fence posts, contained nesting cavities vital to the bluebirds' survival.

However, in recent decades, the eastern bluebird population has recovered nicely. Now the colorful birds are a common sight throughout Minnesota. It's not a coincidence that bluebirds' nesting boxes are also abundant on the landscape.

Bluebirds begin arriving in Minnesota during early March. Nesting occurs throughout May, June and — since most bluebird pairs will raise two broods — even into July. Therefore, it is not too late to put up nesting boxes now. They can be purchased at most stores that sell bird feeding supplies, or you can build your own. The book Woodworking for Wildlife by Carrol L. Henderson contains plans for building nesting boxes for all sorts of wildlife.

Ideal bluebird habitat contains sunny openings where the grass is less than knee-high. Bluebirds depend on spotting their insect prey from a distance and feed more efficiently in open areas. Meadows, farm pastures, and open back yards make perfect bluebird habitats, but bluebirds will reside even in urban locals.

So what's the big deal about having a few bluebirds around? A friend once answered that question like this: "If you have to explain to someone why a person would want to attract bluebirds to their property, then chances are they won't understand."

Bill Marchel, an outdoors writer and photographer, lives near Brainerd.