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

Sage Thrasher Population Trend in Montana

All statesArid-land birds

Sage Thrasher in Montana has fallen sharply: down 55% on the route-weighted index since 1970.

-55%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 →
41Routes 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 Sage 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 →

long arc declinecomputed 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 →

Sage Thrasher has fallen sharply in Montana: down 55% on the route-weighted index since 1970.

Sage Thrasher Population Forecast in Montana

If the recent trend holds, Sage Thrasher in Montana is projected to fall about 83% by 2030 — from 0.64 in 2025 to a central estimate of 0.11 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±66.1%, with 100% of held-out values landing inside the 95% band.

-83%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 →
0.11Projected 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 →
0.00–1.095% 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 →
±66.1%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, Sage Thrasher in Montana is projected to fall about 83% by 2030 — from 0.64 in 2025 to a central estimate of 0.11 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±66.1%, 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 →
20260.190.001.1
20270.170.001.1
20280.150.001.1
20290.130.001.1
20300.110.001.0

Sage Thrasher Survey Routes in Montana

Routes recording Sage 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 →
Brunzell Slough2020252015
Twin Bridges619761968
Polson520251994
Boulder520251969
Lima520252001
Malta419971988
Jordan420171968
Flatwillow 2320212021
Leroy320252009
Chuffey Spring320252018
Glen220251977
Willow Creek 2220251982
Roy220171988
Brusett220231983
Woodman219941994
Flatwillow219921977
Ingomar220241980
Beaverhead220251973
Jordan South220252016
Cleveland119841984
Pryor Mtn.120242000
Shawmut120211979
Forsyth119921988
Sula120162016
Willow Creek119781972

Sage Thrasher Population Trend in Other States

arizonacaliforniacoloradoidahonebraskanevadanew-mexiconorth-dakotaoregonsouth-dakotautahwashingtonwyoming

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