Mountain Bluebird

Sialia currucoides

Mountain Bluebird - Male
Tom Koerner / USFWS / Flickr / CC by 2.0

The bluest of the North American bluebirds, the mountain bluebird has bright blue plumage and a winning personality. Often seen hovering over fields as it hunts for insects, this member of the Turdidae bird family of thrushes is a popular species for birders to add to their life list.

Fast Facts

  • Scientific Name: Sialia currucoides 
  • Common Name: Mountain Bluebird
  • Lifespan: 6-10 years
  • Size: 6.5-8 inches
  • Weight: 1-1.1 ounces
  • Wingspan: 11-14 inches
  • Conservation Status: Least concern

Mountain Bluebird Identification

These colorful songbirds can easily be identified by their bright blue overall plumage, but wear and tear on their feathers can make coloring uneven and birders should know other key field marks to be certain when they see mountain bluebirds. Males are significantly brighter than females, but their underparts are duller and gray-blue or whitish on the lower abdomen and underneath the tail. A gray wash can be seen around the lores and eyes and could create a faint mask-like appearance.

Females have gray upperparts that may show a faint blue wash, but their brightest blue is on their wings and tail. Females’ underparts are gray or white. There is a thin white eye ring and a gray-brown wash on the face. Both males and females may occasionally show a rufous wash on the chest, though this is highly variable and stands out more on females. Both genders have black legs and feet, and their bills are thin, pointed, and black.

Juvenile mountain bluebirds resemble females but show strong buff or white spotting on the breast and head, and their plumage looks more rumpled and disorganized.

While the mountain bluebird is not exceptionally vocal, it does have soft calls with a "burry" quality. The song is a rapid, chirping warble and when these birds do sing, they may vocalize for long periods.

Mountain Bluebird vs. Western Bluebird

Mountain bluebirds and western bluebirds can occasionally be seen together, but they’re easy to tell apart. Western bluebirds have a bold, distinctive brick-red breast with reddish color on their flanks and back as well, whereas mountain bluebirds have only a very faint reddish wash. Western bluebirds also have a bright blue hood that contrasts with their red breast. Females are duller overall, but still show much more red than mountain bluebirds. Birders should also note that western bluebirds generally stick to lower elevations, while mountain bluebirds prefer higher altitudes.

Mountain Bluebird Habitat and Distribution

Mountain bluebirds are generally found at elevations greater than 7,000 feet during the summer months in the mountainous areas of western North America as far north as Alaska. They prefer sparse woodland edges and open areas such as alpine meadows, mountain prairies, and plowed agricultural fields, particularly if there are scattered trees to provide lookout perches. They may also be seen in recently burned areas where the vegetation is more open. These birds can be found year-round in the mountains of Nevada, southeastern Oregon, southern Utah, and Colorado, as well as in similar habitats in northern regions of Arizona and New Mexico.

Migration Pattern

In winter, mountain bluebirds migrate to lower elevations and extend their range further south, including into Mexico. Vagrant birds are occasionally recorded in winter in the Midwest or further east.

Behavior

These are relatively solitary birds but are regularly found in pairs or small family groups, particularly at the end of the breeding season when young birds are maturing and still look to their parents for guidance. In late summer and early fall, flocks of up to 30 or more mountain bluebirds may form.

Diet and Feeding

Mountain bluebirds are generally insectivorous and eat a wide range of both flying and crawling insects, as well as caterpillars and other larvae. They will also eat different types of fruit and berries, especially in fall and winter when insects are scarce.

When feeding, mountain bluebirds can hover extensively and will pounce on prey from the air before taking it to a perch to feed. They will beat larger insects on rocks or branches not only to kill their prey, but to help dismember it before eating.

Nesting

Mountain bluebirds are cavity-nesting birds and will readily nest in bird houses. Male will scout possible nesting sites, but the female bird ultimately chooses where the nest will be. The female builds the nest with grasses, lining a snug cup with finer grasses, strips of bark, and occasionally soft feathers or fur.

Eggs and Young

The three to eight eggs per brood are plain, pale bluish-white. A mated pair of mountain bluebirds will produce one to two broods per year. The female parent will incubate the eggs for 13 to 14 days, and both parents feed the helpless young chicks for an additional 21 to 23 days.

In areas where mountain bluebird habitat overlaps with the eastern bluebird's, the two species can hybridize.

Mountain Bluebird Conservation

Mountain bluebirds are not considered threatened or endangered, but they can be at risk from competition for appropriate nesting sites, especially from house sparrows and European starlings. Choosing bird houses with the proper entrance hole size and taking other steps to deter house sparrows and other invasive birds can help mountain bluebirds have better nesting success.

Tips for Backyard Birders

At the proper altitude within their range, these birds will regularly visit yards where mealworms or suet are offered in open feeders. They will also nest in bird houses of appropriate dimensions. Backyard birders hoping to attract mountain bluebirds should avoid using pesticides that would eliminate that critical food source. Planting trees and shrubs that hold berries and fruit into the winter, particularly grapes and sumac, will provide additional food to encourage these birds to visit. Other steps to attract thrushes can also be helpful in attracting mountain bluebirds.

How to Find This Bird

Mountain bluebirds can be challenging to find. Visiting mountain meadows and pasture areas at high elevations, such as along scenic mountain drives or on routes leading to ski resorts, is the best option for seeing these bright blue birds. Look for mountain bluebirds to be perched on fence posts as they sally back and forth while foraging, or visit feeding stations offering suet or mealworms in mountain areas to see when mountain bluebirds visit.

Mountain Bluebirds in Culture

The mountain bluebird is such a pretty, distinctive bird, it has been honored as the official state bird of Idaho and Nevada. In Idaho, these birds are only summer residents, but they can be seen throughout western and southern Nevada year-round. Idaho adopted the mountain bluebird in 1931 after fierce campaigning by women’s groups and schools, while Nevada adopted the mountain bluebird as its state symbol in 1967 after similar voting and public input.

Explore More Species in This Family

The Turdidae bird family is filled with more than 150 colorful thrushes. Familiar relatives of the mountain bluebird include:

Don’t miss our other wild bird species profiles to learn all about your favorite birds!