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Species · Montana · BBS 2025 Release · 1966–2024

Sage Thrasher Population Trend in Montana

All statesGeneralists

Sage Thrasher in Montana has fallen sharply: down 61% on the route-weighted index since 1970.

-61%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 →
40Routes 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 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 61% 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 85% by 2029 — from 0.65 in 2024 to a central estimate of 0.09 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±65.3%, with 100% of held-out values landing inside the 95% band.

-85%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 →
0.09Projected 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 →
0.00–1.095% 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 →
±65.3%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, Sage Thrasher in Montana is projected to fall about 85% by 2029 — from 0.65 in 2024 to a central estimate of 0.09 (95% range 0.00–1.0). A 5-year backtest shows a typical error of ±65.3%, 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 →
20250.180.001.1
20260.160.001.1
20270.140.001.1
20280.120.001.0
20290.090.001.0

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 Slough1720242015
Polson820241994
Boulder820241969
Beaverhead820241973
Twin Bridges619761968
Winnett620222018
Malta419971988
Jordan420171968
Lima420242001
Flatwillow 2320212021
Glen220231977
Leroy220242009
Roy220171988
Brusett220231983
Woodman219941994
Flatwillow219921977
Ingomar220241980
Custer 2220242024
Jordan South220242016
Roundup220182016
Cleveland119841984
Willow Creek 2120231982
Pryor Mtn.120242000
Shawmut120211979
Forsyth119921988

Sage Thrasher Population Trend in Other States

arizonacaliforniacoloradoidahonebraskanevadanew-mexiconorth-dakotaoregonsouth-dakotautahwashingtonwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.