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

Yellow Warbler Population Trend in Montana

All statesForest birds

Yellow Warbler in Montana has surged: up 76% on the route-weighted index since 1970.

+76%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 →
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 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 76% 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 21% by 2029 — from 9.5 in 2024 to a central estimate of 11 (95% range 8.6–14). A 5-year backtest shows a typical error of ±24%, with 60% of held-out values landing inside the 95% band.

+21%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 →
11Projected 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 →
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 →
±24%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 21% by 2029 — from 9.5 in 2024 to a central estimate of 11 (95% range 8.6–14). A 5-year backtest shows a typical error of ±24%, with 60% 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 →
2025118.314
2026118.414
2027118.514
2028118.514
2029118.614

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 →
Chestnut5320241968
Clyde Park4220242018
Brandenberg3520191968
Reed Point3120241977
Red Rock2920241973
Ninemile2920241993
Fish Creek2820241995
Chinook2820242015
Elliston2720241968
Forsyth2720231980
Clinton2520241975
Freeman Creek2420162015
Muddy Creek2320152015
Hebgen Lake2320242017
Fort Logan2320242018
Libby Dam2220241979
Beaverhead2120241973
Church Hill2120242017
Wise River1920241993
Chuffey Spring1920242016
Cleveland1820241979
East Glacier Park1820242015
Highwood1720241968
Woodman1720241968
Laurel1720221968

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 2026-05-22.