Currently there is not enough scientific data to make a clear judgment on whether one should remove the old nesting material after the breeding season or leave it in the nest box. NatureCraft will provide information as it becomes available. Unlike other bluebird species, male Mountain Bluebirds have no chestnut red on their bodies. The head, back, wings, and tail are a bright sky blue. Males are light blue from the chin to the belly, and grayish-white on the belly and undertail coverts.
Females have brownish-gray upper parts.
The wings, rump, and tail are a pale or light blue. Females sometimes have a pale reddish throat and breast, but more commonly, the throat and breast are gray brown. Juveniles look like adult females, but they are darker and less colorful. Their breasts and sides are streaked with brown. This species song is a deep chur or phew.