The Mountain Bluebird belongs to the Thrush subfamily of birds. It's the largest of bluebirds, with the male sky blue above with lighter blue below. The female is a uniform pale-grayish brown body with sky blue wings and tail
The nest is cup-shaped and made of grasses, shreads of sage, aspen bark, twigs, feathers, and pine needles. The female will lay one pale blue or whitish egg per day until there are 4 to 8 in the nest. Incubation is 13-14 days, and nestlings fledge within 18 to 23 days. At high elevations, there will be only one brood per season vs. two broods per season at lower elevations. The adult bluebird will live about 5 years.