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

American Kestrel Population Trend in California

All statesGeneralists

American Kestrel in California has fallen sharply: down 71% on the route-weighted index since 1970.

-71%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 →
238Routes 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 American Kestrel 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 →

American Kestrel has fallen sharply in California: down 71% on the route-weighted index since 1970.

American Kestrel Population Forecast in California

If the recent trend holds, American Kestrel in California is projected to fall about 63% by 2029 — from 1.5 in 2024 to a central estimate of 0.57 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±23.6%, with 100% of held-out values landing inside the 95% band.

-63%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 →
0.57Projected 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 →
0.00–1.695% 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 →
±23.6%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, American Kestrel in California is projected to fall about 63% by 2029 — from 1.5 in 2024 to a central estimate of 0.57 (95% range 0.00–1.6). A 5-year backtest shows a typical error of ±23.6%, 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 →
20250.710.001.7
20260.680.001.7
20270.640.001.7
20280.610.001.6
20290.570.001.6

American Kestrel Survey Routes in California

Routes recording American Kestrel 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 →
Tres Pinos 22620112005
Moreno1120241968
Niland1020241974
Alderpoint1020121974
Riovista920241968
Hollister620111973
Ravendale620241973
Likely620241971
Yolla Bolly620241974
Coyote620241972
Yreka620191973
South Lake620062006
Tracy 2620242010
Tres Pinos520031968
Alamo River520181974
Imperial Dam520101973
Zamora520241972
Tracy520091992
Yokohl Val419971972
Orange Cove420161972
Lenwood419951977
Coachella Cn420131986
Lake Berryessa420242023
Elsinore Mtn420241970
White River419921972

American Kestrel Population Trend in Other States

alabamaalaskaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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