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Species · California · BBS 2026 Release · 1966–2025

Greater Sage-Grouse Population Trend in California

All statesGame birds

Greater Sage-Grouse in California has surged: up 537% on the route-weighted index since 1977.

+537%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 →
8Routes 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 →
35YearsYears 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 →

No notable trend signals for Greater Sage-Grouse in California. See the full index history below.

Greater Sage-Grouse Population Forecast in California

If the recent trend holds, Greater Sage-Grouse in California is projected to fall about 61% by 2030 — from 0.25 in 2025 to a central estimate of 0.10 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±141.8%, with 80% of held-out values landing inside the 95% band.

-61%Change by 2030TrendPercent 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 →
0.10Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.2695% 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 →
±141.8%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 fall about 61% by 2030 — from 0.25 in 2025 to a central estimate of 0.10 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±141.8%, with 80% of held-out values landing inside the 95% band.19722030
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 →
20260.090.000.26
20270.090.000.26
20280.090.000.26
20290.100.000.26
20300.100.000.26

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
Bodie1320252008
Clear Lk Res819891972
Crowley Lake720251977
Cedarville419781978
Deep Springs119791979
Crestview120252025
Ravendale119941981

Greater Sage-Grouse Population Trend in Other States

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Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.