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

Dusky Grouse Population Trend in Washington

All statesGeneralists

Dusky Grouse in Washington has fallen sharply: down 61% on the route-weighted index since 1992.

-61%Since 1992TrendPercent 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 →
10Routes 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 →
21YearsYears 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 WashingtonNotable 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 Washington: down 61% on the route-weighted index since 1992.

Dusky Grouse Population Forecast in Washington

If the recent trend holds, Dusky Grouse in Washington is projected to stay roughly flat through 2028, near 0.02 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±42.4%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 2028 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 →
±42.4%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 Washington is projected to stay roughly flat through 2028, near 0.02 (95% range 0.00–0.08). A 5-year backtest shows a typical error of ±42.4%, with 100% of held-out values landing inside the 95% band.19712028
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 →
20240.020.000.09
20250.020.000.09
20260.020.000.09
20270.020.000.09
20280.020.000.08

Dusky Grouse Survey Routes in Washington

Routes recording Dusky Grouse in Washington.
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 →
Cloverland420171996
Winthrop320222018
Omak Creek120221996
Keller120041971
Northport120071998
L. Wenatchee120232023
L Pend O Nwr120112011
Curlew120062004
Sullivan Lake 2120152015
Twin Lakes120182015

Dusky Grouse Population Trend in Other States

arizonacoloradoidahomontananevadanew-mexicooregonutahwyoming

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