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Species · California · BBS 2025 Release · 1966–2024

Greater Sage-Grouse Population Trend in California

All statesGeneralists

Greater Sage-Grouse in California has surged: up 397% on the route-weighted index since 1977.

+397%Since 1977TrendPercent 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 →
7Routes 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 →
34YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Greater Sage-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 →

long arc increasecomputed 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 →

Greater Sage-Grouse has surged in California: up 397% on the route-weighted index since 1977.

Greater Sage-Grouse Population Forecast in California

If the recent trend holds, Greater Sage-Grouse in California is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.23). A 5-year backtest shows a typical error of ±286.3%, 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 →
0.07Projected 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 →
0.00–0.2395% 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 →
±286.3%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, Greater Sage-Grouse in California is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.23). A 5-year backtest shows a typical error of ±286.3%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20250.070.000.23
20260.070.000.23
20270.070.000.23
20280.070.000.23
20290.070.000.23

Greater Sage-Grouse Survey Routes in California

Routes recording Greater Sage-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 →
Honey Lake1420211972
Clear Lk Res819891972
Cedarville419781978
Bodie120172008
Deep Springs119791979
Ravendale119941981
Crowley Lake120241977

Greater Sage-Grouse Population Trend in Other States

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