The Mountain Bluebird (Sialia currucoides) is a small thrush found in western North America. They are medium-sized songbirds with sky blue upperparts and whitish underparts. Mountain Bluebirds are primarily found in open habitats like meadows, prairies, and mountainsides. Their breeding range extends from Alaska through western Canada and the western United States. Mountain Bluebirds are a species of Least Concern according to the IUCN Red List, but their populations can fluctuate depending on habitat availability. In this article, we’ll examine if Mountain Bluebirds are rare and some key facts about their population size and conservation status.
Are Mountain Bluebirds Rare?
Mountain Bluebirds are not considered globally rare or threatened species. Their global population size has not been quantified but they have an extremely large range across western North America. Based on their widespread distribution and presence in diverse habitat types, Mountain Bluebirds are evaluated as Least Concern on the IUCN Red List.
However, locally Mountain Bluebirds may be uncommon or rare in areas at the edge of their range. Their numbers also fluctuate in response to changes in habitat or climate. For example, major droughts can temporarily reduce Mountain Bluebird populations if insect prey availability decreases. But in general, these birds remain common and resilient across their core western range.
Mountain Bluebird Population Size
The global population size of Mountain Bluebirds has not been quantified. They are reported to have extremely large range sizes, occupying nearly 2,000,000 square kilometers in their breeding grounds alone. Based on their extensive distribution, Mountain Bluebirds likely number in the millions of individuals worldwide.
In British Columbia, which makes up part of their northern range, Mountain Bluebirds are described as “fairly common” and “widespread.” Breeding Bird Survey (BBS) data from 1966-2019 shows Mountain Bluebirds had a positive population trend (61% increase) in British Columbia during that period.
Further south in California, BBS data indicates Mountain Bluebirds underwent a non-significant population decline of 16% from 1966-2015. However local declines have been more severe in southern California, where habitat loss has reduced breeding populations. Overall in California the species remains common.
Mountain Bluebird Conservation Status
Here is a summary of Mountain Bluebird’s conservation status:
- IUCN Red List: Least Concern
- Global Population: Unknown but likely numbers in the millions
- Population Trend: Generally stable or increasing, with some local declines particularly at southern edge of range
- Threats: Habitat loss, drought, climate change, competition with other bluebird species
Mountain Bluebirds are not considered globally threatened or endangered. Their Least Concern status on the IUCN Red List indicates they are widespread and abundant. However, conservation actions may be needed in areas where populations are declining or threatened by human activities. Providing nesting boxes and protecting open habitats can help sustain Mountain Bluebird populations into the future.
Key Facts about Mountain Bluebird Populations
- Mountain Bluebirds have an extremely large breeding range across western North America.
- They occupy diverse open habitats including meadows, prairies, tundra, savannah, and mountainsides.
- Global population size likely numbers in the millions but has not been accurately quantified.
- Populations generally increased from 1966-2019 according to Breeding Bird Survey data.
- They are common and widespread through most of range, but rare or declining in some peripheral areas.
- Major threats include habitat loss, drought, climate change, and competition with other bluebird species.
- Conservation actions like providing nest boxes and protecting open habitats can sustain populations.
In conclusion, Mountain Bluebirds remain common and resilient across most of their breeding range. While not globally rare or endangered, local declines at the edges of their range highlight the need for continued habitat protections and conservation actions to support Mountain Bluebird populations into the future.
Conclusion
Mountain Bluebirds are evaluated as a species of Least Concern by the IUCN Red List and remain relatively abundant and widespread in appropriate habitat across their large range in western North America. While their global population numbers likely in the millions, quantifying their total population has been challenging. Breeding Bird Survey data generally shows increasing population trends from 1966-2019, though some declines have occurred locally, especially in parts of California. Habitat loss remains the major threat to Mountain Bluebirds, highlighting the need for conservation of open meadows, prairies, and other habitats they utilize. While not globally rare, targeted conservation efforts may be needed in areas where Mountain Bluebirds have declined or face threats from human activity. Overall, Mountain Bluebirds remain a common and iconic songbird of western North America, but continued monitoring and habitat protections can help ensure their populations remain stable into the future.
