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Species · Montana · BBS 2025 Release · 1966–2024

Townsend's Warbler Population Trend in Montana

All statesForest birds

Townsend's Warbler in Montana has surged: up 183% on the route-weighted index since 1970.

+183%Since 1970TrendPercent 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 →
29Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Townsend'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 →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Townsend's Warbler has surged in Montana: up 182% on the route-weighted index since 1970.

Townsend's Warbler Population Forecast in Montana

If the recent trend holds, Townsend's Warbler in Montana is projected to rise about 63% by 2029 — from 2.6 in 2024 to a central estimate of 4.3 (95% range 2.7–5.9). A 5-year backtest shows a typical error of ±53.3%, with 40% of held-out values landing inside the 95% band.

+63%Change 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 →
4.3Projected 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 →
2.7–5.995% 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 →
±53.3%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, Townsend's Warbler in Montana is projected to rise about 63% by 2029 — from 2.6 in 2024 to a central estimate of 4.3 (95% range 2.7–5.9). A 5-year backtest shows a typical error of ±53.3%, with 40% of held-out values landing inside the 95% band.19682029
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 →
20254.12.55.7
20264.12.55.7
20274.22.65.8
20284.22.65.8
20294.32.75.9

Townsend's Warbler Survey Routes in Montana

Routes recording Townsend'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 →
St Regis5120241977
Whitefish Lake3820242016
Fish Creek3520241995
Woodman1620241968
Ninemile1520241993
Threemile Wa1420241993
Logan Pass1120241980
Swan Lake1020242015
Inside Road920241990
Skalkaho919981992
Greenough820041996
Arlee820241968
Greenoagh 3620242015
Cramer Creek520192018
Skalkho-Rye520221999
Painted Rock520221992
Noxon520231995
Elevation Mt420242004
Victor220241993
Clinton220241976
Wise River220222005
Libby Dam120241979
Kalispell119841980
Polson119971990
Sula120181978

Townsend's Warbler Population Trend in Other States

alaskaidahooregonwashingtonwyoming

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