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

California Quail Population Trend in California

All statesGeneralists

California Quail in California has edged up: up 11% on the route-weighted index since 1970.

+11%Since 1970TrendPercent 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 →
218Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable California Quail 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 California Quail in California. See the full index history below.

California Quail Population Forecast in California

If the recent trend holds, California Quail in California is projected to fall about 12% by 2029 — from 11 in 2024 to a central estimate of 10 (95% range 5.8–14). A 5-year backtest shows a typical error of ±20.6%, with 80% of held-out values landing inside the 95% band.

-12%Change 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 →
10Projected 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 →
5.8–1495% 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 →
±20.6%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, California Quail in California is projected to fall about 12% by 2029 — from 11 in 2024 to a central estimate of 10 (95% range 5.8–14). A 5-year backtest shows a typical error of ±20.6%, with 80% of held-out values landing inside the 95% band.19682029
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 →
2025105.815
2026105.814
2027105.814
2028105.814
2029105.814

California Quail Survey Routes in California

Routes recording California Quail 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 →
S Catalina12620221988
Lake Berryessa8020242023
Coalinga7220221973
Oak Grove5720241968
White River5619921972
Jacumba5520241973
Kelso Valley5120241973
Tehama4920221973
Rumsey4720081969
Greenfield4720241973
Lockwood Val4520191970
Jackson4519921972
Parkfield4320241968
Dorris4120191972
Red Bluff3820241968
Poway3519801973
Yolla Bolly3420241973
Colma3219721968
Sanger3020242011
Point Reyes2920231970
Tres Pinos 22920112005
Yokohl Val2819971972
Carmel Val2820241973
Adelaida2820241970
Auburn2719801969

California Quail Population Trend in Other States

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