Western vs. Eastern Bluebird

Western Bluebirds are found across the western United States and central Mexico. Notice the blue throat and bluish belly on the male in the top photo. Contrast that with the brown throat and white belly of the Eastern Bluebird (below). Western Bluebirds often show brown on their backs or scapulars. I took this Western Bluebird’s photo in a park just outside of Missoula, Montana (and the Eastern Bluebird below is from a Christmas Bird Count at Frontenac State Park just south of Red Wing, Minnesota.)

Somebody, probably from the University of Montana, must be studying Western Bluebirds—look at the color bands on this bird’s legs. Research shows that Western Bluebirds are “socially” monogamous, but both sexes also mate outside their pair bond.  The result is that “offspring are not always related to the attendant male.” The pair also get help raising their young, often by adult male relatives or juveniles from previous broods (Guinan et al. 2008).

Unlike Eastern Bluebirds, Westerns prefer edge habitats, and do not favor large, open meadows. Clear-cutting, snag removal, and fire suppression all adversely affect Western Bluebirds.