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Species · California · BBS 2026 Release · 1966–2025

Mountain Quail Population Trend in California

All statesGame birds

Mountain Quail in California has risen sharply: up 55% on the route-weighted index since 1970.

+55%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 →
154Routes 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 Mountain 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 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 →

Mountain Quail has risen sharply in California: up 55% on the route-weighted index since 1970.

Mountain Quail Population Forecast in California

If the recent trend holds, Mountain Quail in California is projected to rise about 35% by 2030 — from 2.2 in 2025 to a central estimate of 2.9 (95% range 0.69–5.1). A 5-year backtest shows a typical error of ±81.6%, with 80% of held-out values landing inside the 95% band.

+35%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 →
2.9Projected 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 →
0.69–5.195% 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 →
±81.6%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, Mountain Quail in California is projected to rise about 35% by 2030 — from 2.2 in 2025 to a central estimate of 2.9 (95% range 0.69–5.1). A 5-year backtest shows a typical error of ±81.6%, with 80% 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 →
20262.90.735.2
20272.90.725.1
20282.90.715.1
20292.90.705.1
20302.90.695.1

Mountain Quail Survey Routes in California

Routes recording Mountain 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 →
Mt Baldy8520241970
Westville5520251971
South Fork Mtn4720222000
Green Valley4320231970
Tuolumne Grove3320251972
Little Truckee2920231997
Hat Creek2820181973
Bartlett Sps2320181972
Lockwood Val2220191970
Longvale2220231972
Pilot Creek2219961994
Cuyamaca Pk1820251971
Pollock Pines1820251997
Lake Hemet1719861971
Burnt Ranch1720161998
Riverton1620251973
Cottage Spgs1519751968
Shasta Lake1420251972
Forest Hill1220251997
Last Chance1220191993
Nubieber1120181970
Tahoe Nf1119941987
Yolla Bolly1020241973
Lake Hemet 2920231993
Stonyford920182015

Mountain Quail Population Trend in Other States

nevadaoregonwashington

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