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

Gambel's Quail Population Trend in California

All statesArid-land birds

Gambel's Quail in California has fallen sharply: down 66% on the route-weighted index since 1970.

-66%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 →
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 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 66% 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 rise about 80% by 2029 — from 0.26 in 2024 to a central estimate of 0.47 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±80.7%, with 100% of held-out values landing inside the 95% band.

+80%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 →
0.47Projected 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 →
0.00–1.395% 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 →
±80.7%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 rise about 80% by 2029 — from 0.26 in 2024 to a central estimate of 0.47 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±80.7%, with 100% 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 →
20250.500.001.4
20260.490.001.4
20270.480.001.4
20280.470.001.4
20290.470.001.3

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
Joshua Tree 22020162013
Niland1920241980
Havasu Lake1720031973
Iron Mtns1520142006
Tecopa1320231979
Parker Dam1120071973
Goldstone1020061968
Lenwood620121975
Cottonwood620191975
Lone Pine619961970
Darwin520052005
Willow Spgs419741973
Oak Grove419711970
Palo Verde420241973
Valley Wells320231969
Glamis320181968
Ivanpah320191989
Essex319961988
Needles319731973
Alamo River320181973
Kelso Valley219751973

Gambel's Quail Population Trend in Other States

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