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Species · Montana · BBS 2026 Release · 1966–2025

Yellow Warbler Population Trend in Montana

All statesForest birds

Yellow Warbler in Montana has surged: up 79% on the route-weighted index since 1970.

+79%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 →
111Routes 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 Yellow 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 →

Yellow Warbler has surged in Montana: up 79% on the route-weighted index since 1970.

Yellow Warbler Population Forecast in Montana

If the recent trend holds, Yellow Warbler in Montana is projected to rise about 14% by 2030 — from 10 in 2025 to a central estimate of 11 (95% range 8.6–14). A 5-year backtest shows a typical error of ±26%, with 80% of held-out values landing inside the 95% band.

+14%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 →
11Projected 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 →
8.6–1495% 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 →
±26%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, Yellow Warbler in Montana is projected to rise about 14% by 2030 — from 10 in 2025 to a central estimate of 11 (95% range 8.6–14). A 5-year backtest shows a typical error of ±26%, with 80% 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 →
2026118.314
2027118.414
2028118.514
2029118.514
2030118.614

Yellow Warbler Survey Routes in Montana

Routes recording Yellow 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 →
Reed Point6220251977
Chestnut4620251968
Clyde Park4620252018
Chinook3220252015
Ninemile3120251993
Highwood3020251968
Clancy3020252015
Red Rock2920251973
Fish Creek2820241995
Forsyth2720231980
Brandenberg2720251968
Hebgen Lake2720252017
Church Hill2520252017
East Glacier Park2420252015
Freeman Creek2420162015
Muddy Creek2320152015
Clinton2220251975
Elliston1920251968
Lima1920251994
Fort Logan1920252018
Woodman1820251968
Wise River1820251993
Willow Creek 21720251982
Beaverhead1520251973
St. Mary 21420252009

Yellow Warbler Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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