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

Peregrine Falcon Population Trend in California

All statesGeneralists

Peregrine Falcon in California has edged up: up 17% on the route-weighted index since 1975.

+17%Since 1975TrendPercent 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 →
41Routes 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 →
40YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Peregrine Falcon 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 Peregrine Falcon in California. See the full index history below.

Peregrine Falcon Population Forecast in California

If the recent trend holds, Peregrine Falcon in California is projected to stay roughly flat through 2029, near 0.04 (95% range 0.01–0.08). A 5-year backtest shows a typical error of ±107.5%, with 60% of held-out values landing inside the 95% band.

n/aChange 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 →
0.04Projected 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 →
0.01–0.0895% 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 →
±107.5%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, Peregrine Falcon in California is projected to stay roughly flat through 2029, near 0.04 (95% range 0.01–0.08). A 5-year backtest shows a typical error of ±107.5%, with 60% of held-out values landing inside the 95% band.19692029
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 →
20250.040.000.08
20260.040.000.08
20270.040.000.08
20280.040.010.08
20290.040.010.08

Peregrine Falcon Survey Routes in California

Routes recording Peregrine Falcon 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 →
Bodega Bay420211977
Cedarville220242024
Benton220192019
Crescent Cty120222017
Honeydew119691969
Iron Gate120182018
Hullville120172017
Orleans 2120142014
Glenn120152015
Hughson120241970
Atwater120122012
Brawley120122012
Gold Hill120112011
Crowley Lake120192014
Tuolumne Grove120112011
Sattley120082008
Longvale120212000
Forest Hill120182018
Calif City119781978
Dorris119951989
Orleans120111975
Clear Lk Res119961996
Alderpoint119851985
Yolla Bolly120182018
Morro Bay120122012

Peregrine Falcon Population Trend in Other States

alabamaalaskaarizonacoloradoconnecticutdelawareidahoindianamainemarylandmichiganminnesotamontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorkoklahomaoregonpennsylvaniatennesseetexasutahvermontvirginiawashingtonwisconsinwyoming

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