BirdAnalyst
Species · Montana · BBS 2025 Release · 1966–2024

Western Bluebird Population Trend in Montana

All statesForest birds

Western Bluebird in Montana has declined: down 32% on the route-weighted index since 1989.

-32%Since 1989TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
15Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
33YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Western Bluebird Trends in MontanaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Western Bluebird in Montana. See the full index history below.

Western Bluebird Population Forecast in Montana

If the recent trend holds, Western Bluebird in Montana is projected to stay roughly flat through 2029, near 0.09 (95% range 0.01–0.17). A 5-year backtest shows a typical error of ±541.3%, with 20% of held-out values landing inside the 95% band.

n/aChange by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.09Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.01–0.1795% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±541.3%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Western Bluebird in Montana is projected to stay roughly flat through 2029, near 0.09 (95% range 0.01–0.17). A 5-year backtest shows a typical error of ±541.3%, with 20% of held-out values landing inside the 95% band.19872029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.090.000.17
20260.090.000.17
20270.090.000.17
20280.090.000.17
20290.090.010.17

Western Bluebird Survey Routes in Montana

Routes recording Western Bluebird in Montana.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Clancy320172017
Libby Dam219921987
Victor220151993
Glen220162007
St Regis220221991
Augusta219991993
Ninemile120241994
Kalispell120221996
Lima119991999
Threemile Wa120152015
Pablo Res.120122012
Polson120221992
Painted Rock120172009
Woodman120222007
Greenoagh 3120172016

Western Bluebird Population Trend in Other States

arizonacaliforniacoloradoidahonevadanew-mexicooregontexasutahwashingtonwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.