Mountain Bluebird

The Mountain Bluebird is a slender, long-winged thrush of open country in the western United States and Canada, notable among bluebirds for lacking any rusty or chestnut tones. Males are an unbroken, brilliant sky blue overall, slightly paler on the belly, giving them an especially vivid appearance in flight against open landscapes. Females are grayish-brown overall with pale blue tinges on the wings, tail, and sometimes the rump, and a faint buffy wash on the breast.

This species favors more open, often treeless habitats than its Eastern and Western relatives, including high-elevation meadows, prairies, and sagebrush country, and it is well known for its graceful, hovering flight while hunting insects.

Key Field Marks

• Male: entirely sky blue, slightly paler below, with no orange or chestnut coloring
• Female: grayish-brown with pale blue on the wings and tail
• Slim body and relatively long wings compared to other bluebirds
• Often seen hovering low over grass while foraging

Similar Species

• Eastern Bluebird: male has an orange breast and throat, unlike the all-blue Mountain Bluebird male.
• Western Bluebird: male has a chestnut breast and often a chestnut back patch, with a blue (not orange) throat, still differing from the uniformly blue Mountain Bluebird.
• Indigo Bunting/Lazuli Bunting (males): smaller, with stout conical seed-eating bills, unlike the bluebird's slimmer, insect-catching bill.

Habitat

Mountain Bluebirds favor open, often treeless or sparsely treed habitats, including high-elevation meadows, alpine and subalpine grasslands, prairies, and sagebrush steppe.

Range

They breed across much of the interior western United States and western Canada, from the Rocky Mountains to the eastern edge of the Pacific ranges, and winter in the southwestern U.S. and Mexico.

Migration

Mountain Bluebirds are migratory, moving from higher-elevation and northern breeding grounds to lower elevations and more southerly wintering areas, often forming large flocks during migration and winter.

Behavior

Unlike other bluebirds that often perch-hunt, Mountain Bluebirds frequently forage by hovering low over open ground, dropping down to catch insects, a distinctive kestrel-like hovering flight technique.

Voice

The song is a soft, low warble, generally quieter than that of other bluebirds; calls include a soft, low "few" note similar to other Sialia species.

Feeding

Insects, especially grasshoppers and beetles caught by hovering or ground-sallying, make up much of the diet during the breeding season, while berries become more important in fall and winter.

Nesting & Breeding

Mountain Bluebirds nest in cavities, including old woodpecker holes, natural crevices, and nest boxes, often in more open and exposed sites than other bluebirds. They typically lay 4-6 pale blue eggs and readily use nest box trails set up along open rangeland.