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

Brown Thrasher Population Trend in Montana

All statesGeneralists

Brown Thrasher in Montana has edged up: up 13% on the route-weighted index since 1970.

+13%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 →
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 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 36% by 2029 — from 0.51 in 2024 to a central estimate of 0.33 (95% range 0.00–0.76). A 5-year backtest shows a typical error of ±44.3%, with 100% of held-out values landing inside the 95% band.

-36%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 →
0.33Projected 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 →
0.00–0.7695% 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 →
±44.3%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, Brown Thrasher in Montana is projected to fall about 36% by 2029 — from 0.51 in 2024 to a central estimate of 0.33 (95% range 0.00–0.76). A 5-year backtest shows a typical error of ±44.3%, with 100% 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 →
20250.340.000.77
20260.340.000.77
20270.330.000.77
20280.330.000.76
20290.330.000.76

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
Lambert720242021
Savage620211968
Cabin Creek520242019
Cleveland320171979
Glasgow320241968
Jordan320161968
Locate320221981
Webster320241979
Westby320242015
Muddy Creek320152015
Flatwillow 2220232011
Malta220191987
Brusett220231982
Circle220231973
Ingomar220151974
Reed Point220231989
Laurel220221968
St Xavier219921982
Chinook220242015
Custer220192019
Sunburst120071987
Virgelle119951979
Harlem120151971
Oswego120241978

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 2026-05-22.