What Is a Mountain Bluebird?

The mountain bluebird (Sialia currucoides) is a highly distinctive songbird species found across western North America. True to its name, the mountain bluebird’s most striking feature is the vivid azure blue plumage exhibited by the males. This color is so deep and rich that it almost appears iridescent from certain angles. Females sport a duller greyish-blue color overall. Both male and female mountain bluebirds have a contrasting white belly and underwing area.  

These bluebirds measure around 6.5-8 inches in length, making them a bit smaller than their eastern and western bluebird relatives. A slender, rounded body shape and large eyes give them an endearing, inquisitive look. Mountain bluebirds belong to the thrush family, renowned for their melodic vocalizations and ability to live in harsher environments like mountainous terrain.

Also Read: Fun Facts About Eastern Bluebird Eggs

Songs and Sounds of the Mountain Bluebird  

For such a small and delicately built songbird, the mountain bluebird’s voice carries an unexpectedly low, rich warbling quality. Their primary song has been described as a simple, plaintive call combining low-pitched churs and gurgling notes. It may start soft and ramp up in volume, similar to a gentle whistle that grows in intensity.  

Males are typically the more vocal birds, using their melancholy yet hopeful-sounding song to attract mates and defend breeding territories each spring. Both sexes also emit harsh scolding tchur and chrrr calls when agitated or signaling alarm. The begging cheep calls of the downy hatchlings are a frequent sound around active nests as parents shuttle food back and forth to the hungry broods.

Mountain Bluebird Breeding and Feeding  

Mountain bluebirds are secondary cavity nesters, meaning they rely on existing tree cavities, rock crevices, or nest boxes rather than excavating their own cavities. The female builds the nest using fine dry grasses, weeds, bark strips, and other plant materials, while shaping it into a cozy inner cup lined with soft feathers or animal fur.  

During the breeding season from April through July, the female lays between 4-8 pale blue eggs. She incubates the clutch for approximately 13-14 days until the eggs hatch. Both parents then feed the helpless hatchlings a diet primarily composed of insects like crickets, grasshoppers, beetles, and larvae. Smaller fruits and berries supplement the nestlings’ diet as well.

Once the juveniles fledge from the nest around 15-20 days old, the family joins up in flocks with other bluebird broods. By late summer and fall, their diet shifts more toward fruits, seeds, and grains in preparation for winter. Mountain bluebirds form larger mixed flocks during the winter months to forage together.

Mountain Bluebird Region and Range

As the name implies, mountain bluebirds inhabit mountainous areas across western North America, from Alaska and western Canada down through the Rocky Mountains into Mexico. Their breeding range is centered in the Intermountain West region, including states like Montana, Idaho, Utah, Wyoming, Colorado, and others. They favor semi-open habitats like alpine meadows, forest edges, ranchlands, and urban areas.

During winter, most mountain bluebird populations migrate to lower elevations and deserts in the southwestern United States and northern Mexico to escape the harshest cold and snow. Some residents may remain year-round in parts of Oregon, Washington, and western Canada if conditions allow.

Also Read: 11 Facts About Female Eastern Bluebirds

Conservation of the Mountain Bluebird

Like many other bluebird species, mountain bluebirds experienced steep declines in the late 19th and early 20th centuries due to practices like unregulated shooting and lack of nesting sites as forests were cleared. Conservation efforts to install nesting boxes, promote sustainable forestry, and protect natural habitats have helped mountain bluebird numbers rebound to healthy levels across much of their range.

However, threats still remain from habitat loss, nesting competition from invasive species like European starlings, and environmental factors like severe weather. Maintaining open meadow habitats, controlling invasive competitors, and continuing nest box programs will be vital for future mountain bluebird population stability. Many land trusts and nature organizations focus specifically on mountain bluebird conservation as a high priority.