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Species · Montana · BBS 2026 Release · 1966–2025

Wilson's Warbler Population Trend in Montana

All statesForest birds

Wilson's Warbler in Montana has edged down: down 18% on the route-weighted index since 1972.

-18%Since 1972TrendPercent 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 →
39Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Wilson's Warbler 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 Wilson's Warbler in Montana. See the full index history below.

Wilson's Warbler Population Forecast in Montana

If the recent trend holds, Wilson's Warbler in Montana is projected to rise about 60% by 2030 — from 0.27 in 2025 to a central estimate of 0.42 (95% range 0.00–0.91). A 5-year backtest shows a typical error of ±57.4%, with 100% of held-out values landing inside the 95% band.

+60%Change by 2030TrendPercent 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 →
0.42Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.9195% 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 →
±57.4%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, Wilson's Warbler in Montana is projected to rise about 60% by 2030 — from 0.27 in 2025 to a central estimate of 0.42 (95% range 0.00–0.91). A 5-year backtest shows a typical error of ±57.4%, with 100% of held-out values landing inside the 95% band.19702030
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 →
20260.420.000.91
20270.420.000.91
20280.420.000.91
20290.420.000.91
20300.420.000.91

Wilson's Warbler Survey Routes in Montana

Routes recording Wilson's Warbler 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 →
Libby Dam520131981
Cleveland519791979
Sula520241978
Swan Lake520212015
Skalkaho519921992
Hebgen Lake520252019
Wise River520251993
Arlee420251970
Logan Pass320251980
Beaverhead319971973
Clancy320232021
Elevation Mt220252005
Clinton219821975
Inside Road220251992
Whitefish Lake220242019
Ninemile220151993
Fish Creek220211997
Noxon219991999
Kalispell120211981
St Mary119921992
Victor120161994
Threemile Wa120131994
Cramer Creek120192005
Glen120172000
Greenough120031998

Wilson's Warbler Population Trend in Other States

alaskacaliforniacoloradoidahomainemichiganminnesotanevadanew-hampshirenew-mexiconew-yorkoregonutahvermontwashingtonwisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.