Last week the Master Naturalist Class took an excursion to Waterworks Hill to look (and listen) for birds. We saw several common Montana species: American robins, northern flickers, dark-eyed juncos, black-billed magpies, and spotted towhees. Instructor Brian Williams heard the call of a mountain bluebird and saw it fly away in the distance, but the untrained ears and eyes of the students were too slow to pick up on it. In lieu of having seen the bird, I decided to do a little research, find a few pictures, and share some bluebird facts here.
We in Western Montana know and love these bright bits of bird blue that come our way in the springtime. Well-named are those perfect, sunny, blue-sky days we call "bluebird days"!
Mountain Bluebirds (Sialia currucoides) are members of the thrush family, and are medium-sized songbirds with a large, round head, chunky body, medium-length tail, and sky-blue feathers. The males in particular stand out, with the bright blue color covering head, body, wings, and tail. Females are a duller color, a greyish-blue overall, with pale sky-blue coloring only on their wings, rump, and tail. In general, it is the males that catch our attention, perhaps because they seem almost impossibly blue. I always forget how richly blue they are, and am surprised, every year, by their vividness.
Mountain bluebirds can be found in open areas and grasslands with scattered trees and bushes, such as agricultural areas and prairie-forest habitats. Their ability to live in open spaces makes them unusual in the thrush family, and helps them increase their population when humans clear land or raise grazing animals. They eat small fruits and insects, which they catch by hovering above their prey and dropping rapidly down to the ground, or by perching and flycatching insects from mid-air.
The females lay 4-8 eggs in nests built of grasses lined with soft bark, hair, or feathers, located in cavities in trees or snags, or in human-made nest boxes. The mountain bluebird's propensity for using nest boxes has made it a fairly easy subject for field research, but has resulted in most of that research being done on nest-box rather than natural mountain bluebird populations.
This bird's summer range extends north-south from Alaska to Arizona and east-west from western Nebraska to California, while in the winter it can be found from Colorado and Nebraska down into central Mexico. It can be found year-round (though populations differ from summer to winter) from central Oregon to northern Arizona and New Mexico. In western Montana, we can look for the mountain bluebird to return in early to mid-March. In other words, now!
When you're out hiking in mountain bluebird habitat, listen for the series of low burry whistles of its song, or the clear, mellow "feeer" or "perf" whistle of its call. You can listen to both sounds here. Happy bluebirding!