BirdAnalyst
Species · Montana · BBS 2026 Release · 1966–2025

Townsend's Warbler Population Trend in Montana

All statesForest birds

Townsend's Warbler in Montana has surged: up 167% on the route-weighted index since 1970.

+167%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 →
30Routes 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 →
57YearsYears 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 167% 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 116% by 2030 — from 1.9 in 2025 to a central estimate of 4.2 (95% range 2.5–5.8). A 5-year backtest shows a typical error of ±79.9%, with 20% of held-out values landing inside the 95% band.

+116%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 →
4.2Projected 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 →
2.5–5.895% 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 →
±79.9%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 116% by 2030 — from 1.9 in 2025 to a central estimate of 4.2 (95% range 2.5–5.8). A 5-year backtest shows a typical error of ±79.9%, with 20% of held-out values landing inside the 95% band.19682030
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 →
20264.02.35.6
20274.02.35.7
20284.12.45.7
20294.12.45.8
20304.22.55.8

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 Regis6320251977
Whitefish Lake3820242016
Fish Creek3520241995
Woodman2620251968
Ninemile1820251993
Threemile Wa1420251993
Inside Road1020251990
Skalkaho919981992
Greenough820041996
Logan Pass620251980
Greenoagh 3620252015
Cramer Creek520192018
Skalkho-Rye520221999
Painted Rock520221992
Noxon520231995
Arlee420251968
Swan Lake420252015
Victor320251993
Elevation Mt320252004
Libby Dam120241979
Kalispell119841980
Polson119971990
Clinton120251976
Sula120181978
Chestnut119751975

Townsend's Warbler Population Trend in Other States

alaskaidahooregonwashingtonwyoming

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