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Species · Montana · BBS 2025 Release · 1966–2024

Dusky Grouse Population Trend in Montana

All statesGeneralists

Dusky Grouse in Montana has fallen sharply: down 61% on the route-weighted index since 1984.

-61%Since 1984TrendPercent 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 →
19Routes 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 →
28YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Dusky Grouse 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 →

Dusky Grouse has fallen sharply in Montana: down 61% on the route-weighted index since 1984.

Dusky Grouse Population Forecast in Montana

If the recent trend holds, Dusky Grouse in Montana is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±42.3%, with 80% of held-out values landing inside the 95% band.

n/aChange 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 →
0.02Projected 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 →
0.00–0.0895% 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 →
±42.3%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, Dusky Grouse in Montana is projected to stay roughly flat through 2029, near 0.02 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±42.3%, with 80% of held-out values landing inside the 95% band.19772029
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 →
20250.030.000.08
20260.030.000.08
20270.030.000.08
20280.030.000.08
20290.020.000.08

Dusky Grouse Survey Routes in Montana

Routes recording Dusky Grouse 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 →
Fish Creek320212021
Logan Pass220241997
Victor120122010
Threemile Wa120121998
Cramer Creek120002000
Greenough120031998
Pryor Mtn.120162016
St Regis120071993
Woodman120182018
Clinton119991984
Elliston120031979
Sula120241977
Chestnut120002000
Reed Point119961996
East Glacier Park120182018
Skalkho-Rye120222021
Greenoagh 3120222015
Ninemile120082008
Painted Rock119981998

Dusky Grouse Population Trend in Other States

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