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Species · California · BBS 2026 Release · 1966–2025

Gambel's Quail Population Trend in California

All statesGame birds

Gambel's Quail in California has fallen sharply: down 63% on the route-weighted index since 1970.

-63%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 →
37Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Gambel's 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 →

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 →

Gambel's Quail has fallen sharply in California: down 62% on the route-weighted index since 1970.

Gambel's Quail Population Forecast in California

If the recent trend holds, Gambel's Quail in California is projected to stay roughly flat through 2030, near 0.45 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±66.2%, with 100% of held-out values landing inside the 95% band.

+1%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 →
0.45Projected 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 →
0.00–1.395% 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 →
±66.2%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, Gambel's Quail in California is projected to stay roughly flat through 2030, near 0.45 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±66.2%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.480.001.4
20270.480.001.4
20280.470.001.3
20290.460.001.3
20300.450.001.3

Gambel's Quail Survey Routes in California

Routes recording Gambel's 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 →
Joshua Tree7620021970
Imperial Dam2820101973
Elizabeth Lk2119701970
Coachella Cn2020131973
Havasu Lake1720031973
Niland1620251980
Iron Mtns1520142006
Tecopa1320231979
Parker Dam1120071973
Goldstone1020061968
Palo Verde820251973
Lenwood620121975
Cottonwood620251975
Lone Pine619961970
Darwin520052005
Joshua Tree 2520252013
Willow Spgs419741973
Oak Grove419711970
Valley Wells320231969
Glamis320181968
Ivanpah320191989
Essex319961988
Lucerne Val320251989
Needles319731973
Alamo River320181973

Gambel's Quail Population Trend in Other States

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