BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Dusky Grouse

PhasianidaeGame birdsDendragapus obscurus

Dusky Grouse has surged: up 411% on the route-weighted index since 1972.

+411%Since 1972TrendPercent 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 →
120RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
52Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Dusky Grouse

The Dusky Grouse (Dendragapus obscurus) is a North American member of the Pheasants, Grouse & Turkeys (Phasianidae). In this analysis it is grouped with the game birds.

Size
12–47 in long (30–120 cm) — a ground-dwelling game bird (typical for the family)
Habitat
Fields, brushland, prairie and the forest floor, where it forages and nests on the ground.
Diet
Seeds, grain, buds, leaves and insects gathered on the ground.
Range
Recorded on 120 Breeding Bird Survey routes across 10 states, most concentrated in the Northern Rockies.
Family
Phasianidae · Game birds

Notable Dusky Grouse TrendsNotable 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 Dusky Grouse. See the full index history below.

Dusky Grouse Population Forecast

If the recent trend holds, Dusky Grouse is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.01). A 5-year backtest shows a typical error of ±68.6%, with 100% 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 →
0.01Projected 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 →
0.00–0.0195% 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 →
±68.6%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, Dusky Grouse is projected to stay roughly flat through 2029, near 0.01 (95% range 0.00–0.01). A 5-year backtest shows a typical error of ±68.6%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.010.000.01
20260.010.000.01
20270.010.000.01
20280.010.000.01
20290.010.000.01

Where the Dusky Grouse Is Detected

BBS routes recording Dusky Grouse, sized by most recent count.

Dusky Grouse Population Trend by State

Dusky Grouse population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizonainsufficient datan/a1
Colorado-78%197542
Idaho-81%19768
Montana-61%198419
Nevadainsufficient datan/a2
New Mexicoinsufficient datan/a1
Oregon+67%199813
Utah-36%199813
Washington-61%199210
Wyoming-65%199311

Dusky Grouse Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Dusky Grouse population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Great Basin-67%19766
Northern Rockies+27%197657
Southern Rockies / Colorado Plateau-68%197556

Dusky Grouse Conservation Status

Our route-weighted index shows it up about 411% since 1972.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.