Western Bluebird

Sialia mexicana

Western Bluebird
Photo courtesy of Tom Grey

Two species of bluebird are found in the western mountains: Western bluebird (Sialia mexicana) south of Canada, up to 9500 ft and Mountain bluebird (Sialia currucoides) up to 12,000 ft. Both Mountain and Western Bluebirds flock together in fall as they migrate to lower altitudes and/or more southerly regions. They are often seen in coastal plains, deserts and mountain foothills from early fall until spring. If food resources are available they may remain in the mountain areas further into winter.

Male has a bright blue hood and back, light blue wings and tail, rusty red breast, white belly. Dark eyes have white ring. Female predominantly gray-blue with a buff colored breast. 6 ½-7 in (15-18 cm)
Song varied, mixture of cheer, cheer-lee, chup, and churchur; call is a chweer
Feeds from a perch, dropping down to the ground to catch insects. Also eats beetles, ants, grasshoppers, crickets, plant fruits. Mistletoe berries are an important food source during winter months.
Males return to the mountains around April to scout for breeding territories. Females arrive a few weeks later to mate. Grass nests are made in old woodpecker holes, tree cavities, and man made nesting boxes. They may occasionally burrow into stream banks. If nesting sites are hard to find, they may drive out resident of an existing nest. Average clutch is 3-5 bluish-green eggs that are incubated 14 days. Young leave the nest after 22-25 days. Two broods may be raised in a season.
They prefer meadows and open woods; lower elevation coniferous forests.
Found in southern half of British Columbia and western Alberta, south to Baja California and Central Mexico; along the western Rocky Mtns to TX.
Bluebirds capture food in three ways: Perching: They perch on a branch with a good view of the immediate vicinity; sitting quietly. When animal or plant food is spotted, the birds fly to the ground to capture it. This method conserves energy. Flycatching: Birds chase insects through air; this uses a lot of energy. This method is most often used during the nesting period when a lot of food needs to be captured for their young. Hovering: Rapid wing-flapping to keep bird in a fixed position in the air. They can look out 10-20 ft, spy food, and drop down to get it. This method is most often used by the Mountain Bluebirds.

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