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

Brown Thrasher Population Trend in Montana

All statesForest birds

Brown Thrasher in Montana has edged up: up 24% on the route-weighted index since 1970.

+24%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 →
49Routes 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 Brown Thrasher 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 Brown Thrasher in Montana. See the full index history below.

Brown Thrasher Population Forecast in Montana

If the recent trend holds, Brown Thrasher in Montana is projected to fall about 43% by 2030 — from 0.60 in 2025 to a central estimate of 0.34 (95% range 0.00–0.78). A 5-year backtest shows a typical error of ±44.6%, with 100% of held-out values landing inside the 95% band.

-43%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 →
0.34Projected 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 →
0.00–0.7895% 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 →
±44.6%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, Brown Thrasher in Montana is projected to fall about 43% by 2030 — from 0.60 in 2025 to a central estimate of 0.34 (95% range 0.00–0.78). A 5-year backtest shows a typical error of ±44.6%, with 100% 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 →
20260.350.000.79
20270.350.000.79
20280.350.000.78
20290.340.000.78
20300.340.000.78

Brown Thrasher Survey Routes in Montana

Routes recording Brown Thrasher 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 →
Wolf Point1120242015
Lambert820252021
Miles City820252015
Hehn Draw720252016
Webster420251979
Brandenberg420251969
Saco420252016
Cleveland320171979
Glasgow320251968
Jordan320161968
Savage320251968
Locate320221981
Muddy Creek320152015
Flatwillow 2220232011
Malta220191987
Brusett220231982
Circle220231973
Ingomar220151974
Reed Point220231989
Laurel220221968
St Xavier219921982
Chinook220252015
Westby220252015
Custer220192019
Cabin Creek220252019

Brown Thrasher Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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