Mountain bluebirds are a beautiful species of thrush that live predominantly in the western United States and Canada. Their bright blue plumage and lovely songs make them a delight to see in the wild. But exactly where do these birds make their homes?
Mountain Bluebird Habitat
Mountain bluebirds thrive in open, treeless areas at relatively high elevations. They are found in mountains, high plateaus, and foothills across the western half of North America. Their preferred habitat includes:
- Alpine meadows
- Mountain parks
- Open ponderosa pine forests
- Burnt-over areas with snags for nesting
- River valleys
The key requirements seem to be open terrain, short vegetation, and suitable nesting sites. Mountain bluebirds perch on wires, rocks, low bushes, or burnt snags as they hunt for insects. Access to berries and seeds is also important during the non-breeding season.
Western Mountain Range
The mountain bluebird has a stronghold across the mountain ranges of the western United States and Canada. Some of the prime locations include:
- Rocky Mountains – This vast mountain range stretching from New Mexico to Alaska offers ideal habitat for mountain bluebirds at elevations between 5,000-12,000 feet.
- Sierra Nevada – The California section of this range bisecting the state provides important summer grounds and migration habitat.
- Cascades – These mountains running through British Columbia, Washington and Oregon have plentiful alpine habitat for nesting bluebirds.
- Coast Range – Lower elevation areas along this range paralleling the Pacific Coast offer habitat, especially in winter.
The mountain bluebird is considered a common summer resident and breeder across many of these western mountain ranges. The birds migrate down in elevation or latitude during the winter months when alpine conditions get too harsh.
Rocky Mountain Range
The Rocky Mountains offer excellent habitat for mountain bluebirds across high elevations and open terrain. Some specific areas where they are found include:
- Banff National Park, Alberta
- Grand Teton National Park, Wyoming
- Glacier National Park, Montana
- Mount Evans, Colorado
- San Juan Mountains, Colorado
Nest boxes and bird feeders in mountain towns and ski resorts provide habitat for bluebirds in winter. Summer sightings are common along high mountain trails, roads, and alpine meadows.
Sierra Nevada Range
The Sierra Nevada mountains form an important breeding area for mountain bluebirds in California. Some top spots include:
- Yosemite National Park
- Kings Canyon National Park
- Mammoth Lakes area
- Lake Tahoe Basin
- Lundy Canyon
Alpine meadows with wildflowers and scattered conifers above 8,000 feet are preferred. The bluebirds migrate downslope for winter, some crossing the Central Valley to the Coast Ranges.
Other Western States
In addition to the major mountain ranges, mountain bluebirds occupy suitable habitat across many other areas of the western U.S. Some prime states include:
- Arizona – Found across higher elevations including San Francisco Peaks. Migrates south and downward in winter.
- Colorado – Widespread in summer across mountains, foothills and high valleys. Descends eastward and southward in winter.
- Idaho – Common summer resident. Found nesting south through Rocky Mountains region.
- Montana – Abundant in summer across mountain ranges and open hills. Winters across lower elevations.
- Nevada – Local populations breed in Wassuk Range, Toiyabe Range and other high elevation sites.
Suitable habitat exists for mountain bluebirds throughout higher elevation areas across the interior west. Migratory patterns vary depending on the severity of winter weather.
Western Canada
Decent populations of mountain bluebirds can be found inhabiting the western provinces of Canada during the spring and summer. Key areas include:
- British Columbia – Abundant along eastern slopes of Coast Mountains. Also found in Okanagan Valley and across southern BC.
- Alberta – Common summer resident in Rocky Mountains including Banff and Jasper National Parks.
- Saskatchewan – Localized breeding populations in Cypress Hills and northwestern mountain regions.
- Manitoba – Rare summer residents along Riding Mountain and Duck Mountain.
The mountain bluebird’s Canadian range becomes patchier further north and east. Winter habitat likely shifts southward and downward in elevation as needed.
Breeding Habitat
Mountain bluebirds nest in tree cavities in open mountain terrain. Good nesting locations include:
- Aspen groves
- Forest edges and openings
- Burnt-out conifers with snags
- Fence posts and power poles
- Nest boxes put up for bluebirds
The female builds a neat cup nest of grasses and pine needles inside the cavity. She lays about 5-7 light blue eggs and incubates them for 13-17 days. The altricial nestlings are fed insects by both parents, fledging in around 22-27 days.
Ideal Nest Sites
Mountain bluebirds are very particular about their nest sites. They prefer cavities that offer:
- An entrance hole around 1.5 inches wide
- A cavity depth of 8-12 inches
- A height of 4-15 feet off the ground
- Protection from predators and the elements
Natural and artificial sites meeting these parameters are readily used by bluebirds. Nest boxes specifically designed for mountain bluebirds can effectively boost breeding habitat.
Wintering Areas
As alpine summer habitat becomes unsuitable, mountain bluebirds migrate to lower elevations or more southerly latitudes for the winter. Mild weather and food availability are key factors.
Western Wintering Sites
Some major wintering areas in the western states include:
- Southern Arizona
- Southern New Mexico
- Southern California coast
- Eastern slopes of Coast Range
- Willamette Valley, Oregon
- Lower elevations of Great Basin
- Mild areas of Colorado Plateau
Winters with ample berries and open woodlands provide the best habitat. Some bluebirds remain year-round in sufficiently mild climates.
Mexico and Central America
Most mountain bluebird populations migrate south into Mexico for the winter months. How far south they travel depends on the harshness of the weather. Their winter range extends from northern Mexico to Nicaragua.
Country | Key Wintering Areas |
---|---|
Mexico | Northern and central highlands. South to Oaxaca. |
Guatemala | Highlands. Southwest to El Salvador. |
Honduras | Interior highlands. South to Nicaragua. |
The mountain bluebirds occupy open, mountainous areas and adjacent agricultural regions. Mild winters allow them to find sufficient food.
Seasonal Migration
Mountain bluebirds are short to medium-distance migrants between their breeding and wintering grounds. Their migration covers a looping pattern due to the north-south orientation of mountain ranges.
Spring Migration
The timing of spring migration depends on weather and location:
- Early March – Arizona, New Mexico, California
- Mid March – Colorado, Oregon, Idaho, Utah
- Late March – Montana, Wyoming, Nevada
- Early April – Canada
The bluebirds generally follow mountain valleys northward as the snow line recedes. This allows them to stop periodically to feed and rest.
Fall Migration
Mountain bluebirds start heading south again in late summer and early fall:
- Early August – Canadian Rockies
- Late August – Montana, Wyoming
- Early September – Colorado, Idaho, Oregon
- Late September – California, Arizona, New Mexico
They may wander some after breeding before migrating south in search of winter habitat. The birds migrating farther south tend to leave earlier.
Threats and Conservation
Mountain bluebird numbers dropped over much of their range during the 20th century due to habitat loss and competition from European starlings and house sparrows for nesting cavities. However, populations have rebounded somewhat in recent decades.
Major Threats
Some ongoing threats to mountain bluebirds include:
- Reduction in nesting cavities from forest management practices
- Competition with non-native birds for nest sites
- Decline of burrowing mammal populations
- Increased severe weather events
- Climate change shrinking alpine habitat
Conservation Actions
Various conservation measures are helping mountain bluebird populations recover:
- Eradication and control of invasive birds
- Installation of nest boxes in strategic locations
- Protection of high elevation breeding areas
- Promotion of rangeland management practices that maintain habitat
- Reintroduction programs in some areas like California’s central coast
Continued habitat management and access to nesting sites will be key for sustaining mountain bluebird populations into the future.
Conclusion
In summary, mountain bluebirds inhabit open, high elevation terrain across the western half of North America. Major mountain ranges like the Rockies and Sierras provide summer breeding habitat. Mild winters are spent at lower elevations or as far south as Central America. Conserving prime habitat and nesting cavities will help ensure the future of these beautiful alpine thrushes.