Mountain Bluebirds

The Mountain Bluebird

  • travels in flocks during winter, often with Western Bluebirds and Sparrows
  • is a highly aggressive bird
  • will sometimes obtain its food by hovering in the air a metre or more above the ground in a hawk-like manner

The population was in decline and perhaps doomed to extinction before bird lovers across North America began in the 1920s to build nest boxes.

Description

Three species of bluebird are found in North America: the Mountain Bluebird Sialia currucoides, the Eastern Bluebird Sialia sialis, and the Western Bluebird Sialia mexicana.

Bluebirds belong to the thrush family, whose members are found throughout much of the world. Another of North America’s well-loved birds, the American Robin, is also a thrush.

The Mountain Bluebird is a little larger than a House Sparrow but smaller than an American Robin. The back, wings, and tail of the male are a bright azure-blue, and the throat and breast are a lighter blue, which fades to white on the abdomen.

On the female, the flight feathers and tail are pale blue and the head and back are a mixed wash of blue and grey. The throat is brownish-ash, blending to white on the lower breast. Immature birds resemble females, except for the mottled breast characteristic of all juvenile members of the thrush family.

Signs and sounds

After working the fence line for some time, the Mountain Bluebird may disappear over the next ridge or clump of trees, leaving behind a soft warbling song. It has a louder song, which is heard most often in pre-dawn hours, during the breeding season.

Habits and Habitat

The Mountain Bluebird’s preferred habitat is sparsely treed grasslands. They require cavities for nesting. During winter, Mountain Bluebirds travel in flocks, often with Western Bluebirds and Sparrows, and feed on insects and small fruit, such as mistletoe, hackberry, and currants. They typically begin to move north in March, but often arrive in northern latitudes when snow still blankets much of the ground and temperatures still dip below -20°C. These hardy birds can usually withstand short spells of cold and stormy weather; however, during prolonged severe conditions they may freeze or starve to death.

Mountain Bluebirds sometimes migrate alone but more often travel in flocks of up to 50 birds (rarely up to 200). They travel during the day at a leisurely pace, stopping frequently to feed. They can sometimes be seen strung like brilliant blue jewels along a barbed wire fence, scanning bare patches of ground for weed seeds and dead insects. Highly aggressive birds, they usually sit at least a metre apart. There is a continual flashing of blue, as first one and then another leaves its perch momentarily to pick up a tasty morsel.

Unique characteristics

When elevated perches are not available, the Mountain Bluebird, unlike other members of the thrush family, will obtain most of its food by hovering in the air a metre or more above the ground in a hawk-like manner, as it searches the earth below for food.

Distribution

mountain_bluebird_map_bigThe Mountain Bluebird inhabits western North America. Its breeding range extends from the Yukon Territory, south through British Columbia east of the Coast Range. It breeds as far east as eastern Manitoba.

The Mountain Bluebird is the most migratory bluebird species, although many individuals simply move locally to lower elevations.

As for other bluebirds, the Eastern Bluebird, with its deep sky-blue back and crown and chestnut-red throat and breast, is found from southern Saskatchewan to Nova Scotia, along the east coast to Florida, and around the Gulf of Mexico to western Texas. The Western Bluebird, which is characterized by a blue throat and rusty upper back and breast, shares some of the Mountain Bluebird’s range in southwestern Canada. It occupies southern British Columbia through southern California into central Mexico and northward up through New Mexico to western Montana. It is scarcer than the Mountain Bluebird, except west of the coast ranges.

——— reprinted with permission from Environment Canada, “Hinterland Who’s Who”.