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

Mountain Quail Population Trend in California

All statesGeneralists

Mountain Quail in California has increased: up 49% on the route-weighted index since 1970.

+49%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 →
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 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 →

No notable trend signals for Mountain Quail in California. See the full index history below.

Mountain Quail Population Forecast in California

If the recent trend holds, Mountain Quail in California is projected to rise about 28% by 2029 — from 2.3 in 2024 to a central estimate of 3.0 (95% range 0.76–5.2). A 5-year backtest shows a typical error of ±71.5%, with 80% of held-out values landing inside the 95% band.

+28%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 →
3.0Projected 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 →
0.76–5.295% 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 →
±71.5%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 28% by 2029 — from 2.3 in 2024 to a central estimate of 3.0 (95% range 0.76–5.2). A 5-year backtest shows a typical error of ±71.5%, 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 →
20253.00.795.2
20263.00.785.2
20273.00.775.2
20283.00.765.2
20293.00.765.2

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
South Fork Mtn4720222000
Green Valley4320231970
Little Truckee2920231997
Hat Creek2820181973
Cuyamaca Pk2720241971
Bartlett Sps2320181972
Lockwood Val2220191970
Longvale2220231972
Pilot Creek2219961994
Pollock Pines2020241997
Lake Hemet1719861971
Tuolumne Grove1720241972
Burnt Ranch1720161998
Cottage Spgs1519751968
Westville1420241971
Last Chance1220191993
Nubieber1120181970
Shasta Lake1120121972
Tahoe Nf1119941987
Yolla Bolly1020241973
Lake Hemet 2920231993
Forest Hill920221997
Stonyford920182015
Onyx819981976

Mountain Quail Population Trend in Other States

nevadaoregonwashington

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