BirdAnalyst
Species · California · BBS 2026 Release · 1966–2025

Cooper's Hawk Population Trend in California

All statesBirds of prey

Cooper's Hawk in California has risen sharply: up 62% on the route-weighted index since 1970.

+62%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 →
162Routes 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 Cooper's Hawk 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 →

Cooper's Hawk has risen sharply in California: up 61% on the route-weighted index since 1970.

Cooper's Hawk Population Forecast in California

If the recent trend holds, Cooper's Hawk in California is projected to fall about 32% by 2030 — from 0.20 in 2025 to a central estimate of 0.14 (95% range 0.05–0.22). A 5-year backtest shows a typical error of ±39.9%, with 100% of held-out values landing inside the 95% band.

-32%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 →
0.14Projected 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 →
0.05–0.2295% 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 →
±39.9%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, Cooper's Hawk in California is projected to fall about 32% by 2030 — from 0.20 in 2025 to a central estimate of 0.14 (95% range 0.05–0.22). A 5-year backtest shows a typical error of ±39.9%, with 100% 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 →
20260.130.050.22
20270.130.050.22
20280.140.050.22
20290.140.050.22
20300.140.050.22

Cooper's Hawk Survey Routes in California

Routes recording Cooper's Hawk 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 →
Sawmill Mtn419931974
Moreno320251983
Lockwood Val320111976
Jofegan 2220242024
Wildrose220212021
Santa Ynez220131976
Orange Cove220161974
Arvin220132013
Jackson219841975
Longvale220111998
Redding219771977
Offield Mtn219781973
Coyote220231976
Copperopolis220141975
Waterman Gap220252002
Cleveland Nf219961996
Tres Pinos 2220092005
Harbor Lake 2220242019
Alamar220002000
Horse Creek120171977
Crescent Cty119941979
Honeydew120141984
Holmes120242024
Red Bluff120212010
Eagle Lake120031974

Cooper's Hawk Population Trend in Other States

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

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