Mountain Bluebird
Mountain Bluebird has surged: up 253% on the route-weighted index since 1969.
About the Mountain Bluebird
The Mountain Bluebird (Sialia currucoides) is a North American member of the Thrushes (Turdidae). In this analysis it is grouped with the forest birds.
- Size
- 6–11 in long (15–28 cm) — a medium songbird (typical for the family)
- Habitat
- Woodlands and forest edges, including wooded suburbs and parks.
- Diet
- Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
- Range
- Recorded on 768 Breeding Bird Survey routes across 15 states, most concentrated in the Southern Rockies / Colorado Plateau.
- Family
- Turdidae · Forest birds
Notable Mountain Bluebird Trends
Mountain Bluebird has surged in surveyed states: up 252% on the route-weighted index since 1969.
Mountain Bluebird Population Forecast
If the recent trend holds, Mountain Bluebird is projected to rise about 34% by 2029 — from 0.67 in 2024 to a central estimate of 0.90 (95% range 0.60–1.2). A 5-year backtest shows a typical error of ±58.4%, with 0% of held-out values landing inside the 95% band.
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.86 | 0.56 | 1.2 |
| 2026 | 0.87 | 0.57 | 1.2 |
| 2027 | 0.88 | 0.58 | 1.2 |
| 2028 | 0.89 | 0.59 | 1.2 |
| 2029 | 0.90 | 0.60 | 1.2 |
Where the Mountain Bluebird Is Detected
BBS routes recording Mountain Bluebird, sized by most recent count.
Mountain Bluebird Population Trend by State
| Alaska | insufficient data | n/a | 3 |
| Arizona | -73% | 1970 | 27 |
| California | -31% | 1971 | 57 |
| Colorado | +166% | 1970 | 113 |
| Idaho | -14% | 1971 | 49 |
| Montana | +24% | 1970 | 86 |
| Nebraska | -79% | 1982 | 4 |
| Nevada | -43% | 1970 | 24 |
| New Mexico | -48% | 1970 | 46 |
| North Dakota | +317% | 1974 | 11 |
| Oregon | -35% | 1970 | 79 |
| South Dakota | +146% | 1969 | 23 |
| Utah | +48% | 1970 | 95 |
| Washington | +293% | 1970 | 34 |
| Wyoming | +187% | 1970 | 117 |
Mountain Bluebird Population Trend by Region
Bird Conservation Regions are the ecological unit for trends.
| Northern Pacific Rainforest | -67% | 1970 | 17 |
| Great Basin | -11% | 1970 | 148 |
| Northern Rockies | -7% | 1970 | 206 |
| Prairie Potholes | -61% | 1987 | 9 |
| Sierra Nevada | -72% | 1971 | 22 |
| Southern Rockies / Colorado Plateau | +42% | 1970 | 225 |
| Badlands and Prairies | +46% | 1969 | 90 |
| Shortgrass Prairie | -36% | 1970 | 22 |
| Coastal California | -86% | 1971 | 8 |
| Sierra Madre Occidental | -26% | 1970 | 12 |
| Chihuahuan Desert | -91% | 1974 | 5 |
Mountain Bluebird Conservation Status
Our route-weighted index shows it up about 252% since 1969.
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.