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

Sooty Grouse Population Trend in California

All statesGeneralists

Sooty Grouse in California has risen sharply: up 62% on the route-weighted index since 1976.

+62%Since 1976TrendPercent 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 →
42Routes 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 →
47YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Sooty Grouse Trends in CaliforniaNotable 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 Sooty Grouse in California. See the full index history below.

Sooty Grouse Population Forecast in California

If the recent trend holds, Sooty Grouse in California is projected to stay roughly flat through 2028, near 0.07 (95% range 0.01–0.12). A 5-year backtest shows a typical error of ±151.9%, with 80% 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 →
0.07Projected 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 →
0.01–0.1295% 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 →
±151.9%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, Sooty Grouse in California is projected to stay roughly flat through 2028, near 0.07 (95% range 0.01–0.12). A 5-year backtest shows a typical error of ±151.9%, with 80% of held-out values landing inside the 95% band.19732028
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 →
20240.070.010.12
20250.070.010.12
20260.070.010.12
20270.070.010.12
20280.070.010.12

Sooty Grouse Survey Routes in California

Routes recording Sooty Grouse in California.
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 →
Lakeshore520071989
Genesee420152012
Paxton320072007
Korbel319911976
Rio Dell319731973
Pilot Creek219961994
Hiouchi220142003
Junction Cty219821973
Pine Mountain219971997
Friday Ridge220231998
Hat Creek220171974
Crescent Cty119901990
Honeydew120062006
Holmes120021976
Forest Hill 2120052005
Lassen Park119891977
Eagle Lake119941994
Ship Mtn.120161995
Westville120172007
White River119801980
Dardanelle120081987
Lonesome Rdg120111994
Dirigio120052005
Tionesta120181999
French Gulch120042002

Sooty Grouse Population Trend in Other States

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