The mountain bluebird, also called the Arctic bluebird and Rocky Mountain bluebird, has an average length of 6.5 to 7.75 inches (16.5 - 20 cm). Males sing a clear short warble, higher pitched than that of the eastern bluebird. Males are all turquoise blue with a paler blue and white belly below. The female's coloring is a dull brown to gray with blue on the rump, wing tips, and tail.
The mountain bluebird is a common summer resident in the western third of the state, particularly in the Black Hills. They can be found at all elevations. There are occasional reports of this bluebird wintering in the Badlands area and similar habitats in the southwestern corner of the state. They are rare migrants through the eastern areas of the state. South Dakota populations are stable, but national populations are considered low.
The mountain bluebird's habitat includes open areas and meadows and
open canyons with scattered trees. These bluebirds are cavity nesters,
but they are unable to excavate their own cavities. They are totally dependent
on holes abandoned by birds such as woodpeckers or nest boxes provided
by bluebird enthusiasts. The nests are built primarily of grasses, with
pine needles, weed stems, and rootlets as common additions. Breeding pairs
maintain a home territory of about one acre, and defend it against other
The mountain bluebirds feed on live insects throughout most of the year eating numerous beetles, weevils, grasshoppers, and
caterpillars, to name a few. To catch insects, they dart out from a low exposed perch or hover and then drop to the ground. In
addition to insects, they will also eat fruits such as currants, elderberries, and cedar berries.
Mountain bluebirds commonly have 4 or 5 eggs, but the range is 3 to 8. Their eggs are pale blue in color (rarely white) and require an incubation period of 14 days. Successful early nesters may raise a second brood. The nests are built of grasses, weed stems, and rootlets in a natural or man-made cavity. Mountain bluebirds are very tolerant of human activity and will nest in and around buildings located in open areas.
The most common reasons for nest failure are domestic cats, raccoons raiding nest cavities, nest parasites such as blow fly larvae, and competition with the more aggressive house sparrow and European starling. Saving of dead and dying trees and rotting wood fence posts, along with the installation and maintenance of nest boxes, can have positive impacts on local populations.
The eastern bluebird is a small thrush, 6.5 to 7 inches (16.7 - 17.7
cm) in length and closely related to the American robin. The male has a
brilliant blue head, back, wings, and tail, and a rust-colored throat and
breast. The female has pale blue wings and tail, a gray-blue head and back.
The throat and breast are pale rust.
In South Dakota, the eastern bluebird is considered an uncommon summer resident throughout the state. It is more common in the James River Valley and eastward. They migrate from their winter quarters in the southern United States in early spring, usually arriving in South Dakota during the last half of March.
Eastern bluebirds are cavity nesters, wholly dependent on several species of woodpeckers to excavate holes in rotting tree limbs and trunks, or man-made artificial cavities called nest boxes. Bluebirds prefer natural cavities or nest boxes located in sparsely wooded habitats with low thin ground cover. They are most often found in grazed pastures, large parks, golf courses, or cemeteries.
Females construct a cup-shaped nest made entirely of dry grass usually during the first 3 weeks of April. Full clutches of 4 to 6 blue, sometimes white, eggs are laid by the first 2 weeks of May. Eggs hatch after an incubation period of approximately 12 days. The young remain in the nest, cared for by both adults, approximately 18 days before fledging. A second nest by the same pair is usually initiated within a week after the first brood fledges.
The eastern bluebird population in North America has decreased due to habitat loss, use of pesticides to reduce insect populations, and competition with other bird species. Critical nesting habitat is lost by the trimming of dead branches and removal of dead trees from orchards and shelterbelts. Bluebirds cannot compete with the English sparrow and European starling, two introduced European birds that also nest in natural cavities. Construction of a nest box trail increases bluebird populations. Detailed instructions will be provided in a Nest Box Trail fact sheet in the Dakota Projects Chapter.
SDOU, 1991. The Birds of South Dakota, NSU Press, Aberdeen, SD 57401.
Terres, John K. 1980. The Audubon Society Encyclopedia of North American Birds.
Stokes, Donald and Lillian, 1991. The Bluebird Book. Little, Brown and Company.
Scriven, D. 1989. Bluebirds in the Upper Midwest, A Guide to Successful Trail Management. Bluebird Recovery Program,
Audubon Chapter of Minneapolis, P.O. Box 566, Minn., MN 55458.
Woodworking for Wildlife , a book by C.L. Henderson, 1984. Mongame
Wildlife Program, Minnesota Department of Natural
Resources, Box 7, 500 Lafayette Road, St. Paul, MN 55155.
Segment #103 Bluebirds. South Dakota Outdoor Guide, a video produced by Steve Lind. South Dakota Public TV. (The return of bluebirds to the Waubay National Wildlife Refuge bluebird trail) May be loaned from the SD State Library.
North Central Bluebird Recovery Team. They publish a Bluebird Directory once a year listing names and addresses of team
members who monitor bluebird boxes. They also publish plans and information on species of birds which nest in man-made boxes. Hultz Hall, Fargo, ND 58105.
Dennis Skadsen, RR 1, Box 113, Grenville, SD 57239.
Duane Weber, 1212 Canal Street, Custer, SD 57730. 1995.
Dr. Dan Tallman, Northern State University, Aberdeen, SD 57401.
Publication of the Bluebirds fact sheet was funded by the South Dakota Department of Game, Fish and Parks, Division of Wildlife, Pierre, SD.