Mountain Bluebird

Sialia currucoides

The Mountain Bluebird is six to seven inches in length. It has a small, pointed black bill and black legs and feet. The male is a deep sky blue above and a paler blue below with a white stomach.

The female is a duller blue-gray on her wings with a gray throat, back and crown.

These bluebirds are characterized by an overall blue wash. They lack the bold rufous coloring of Western Bluebirds.

Males are a striking sky-blue color. Females are predominantly gray with a bluish tint, especially on the wings and tail.

Females have a white eye-ring, which males lack, and some females may have some light rufous on their throats and breasts.

Mountain Bluebird Male

Length: 6.3–7.9 in (16–20 cm)

Weight: 1.1 oz (30 g)


A common sight in ranchland and other open areas of the American West.

The male Bluebird is a breathtaking brilliant sky blue.

It prefers more open habitats than the other bluebirds and can be found in colder habitats in winter.

Mountain Bluebirds occur in varied, open terrain, more open than the habitat of Western Bluebirds. They are found in alpine parklands, and also at lower elevations in steppe areas, open woodlands with Ponderosa pine, forests openings, clearings, and logged areas where a few snags have been left.


The bluebird diet consists of a combination of insects and berries Insects make up a larger percentage of their diet than is the case with other thrushes.

Bluebirds hover just above the ground looking for insects. When it spots one, it swoops down and snatches if up. It may also swoop down on its prey from a perch in a tree.

In the winter, the Bluebirds travel in small flocks, sometimes with sparrows and western bluebirds, and forage for insects and berries.


The males usually arrives at the breeding site first. They select a nesting site in a tree cavity, an old woodpecker hole or in a rocky crevice. When the females arrive, the males fly in and out of their sites and call out, trying to attract the interest of a female.

Once a pair has mated, the female will build a nest of plant fibers and bark while the male guards her and the nesting site. The female lays four to seven eggs at a rate of one egg per day. The female incubates the eggs.

The chicks hatch after about 13 days. The male brings food to the female and the chicks.

The chicks fledge when they are 22-23 days old, but may stay with their parents for another two months. Sometimes a pair will have a second brood during the breeding season.

Cavity-nesters, they rely on natural holes in trees, old woodpecker holes, and man-made cavities for nesting spots. If a traditional cavity can't be located, they will nest in cliff holes, dirt banks, or old swallow nests.

The female selects the cavity, and both build a loose cup-nest with stems, grass, and twigs, lined with softer materials.


The most migratory of the bluebirds, most Mountain Bluebirds leave the nesting grounds in September or October for their wintering grounds in the southwestern United States and Mexico, returning to the nesting grounds in March.

They migrate short distances, sometimes forming large flocks in the winter at low elevations in Ponderosa pine and juniper forest.


Since much of their nesting habitat is remote, Mountain Bluebirds have been less affected than other species by nest site competition with starlings, House sparrows. Artificial nest boxes have helped keep overall population numbers healthy. Nest boxes have allowed for range expansion into new habitats where they previously had no place to nest. In the past century, there has been a decline in some locations.

Eastern Bluebirds

Western Bluebirds

Mountain Bluebirds and other Backyard Birds

Nest Boxes for Bluebirds and Others

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