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

Bald Eagle Population Trend in California

All statesGeneralists

Bald Eagle in California has surged: up 895% on the route-weighted index since 1975.

+895%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 →
58Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bald Eagle 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 →

Bald Eagle has surged in California: up 895% on the route-weighted index since 1975.

Bald Eagle Population Forecast in California

If the recent trend holds, Bald Eagle in California is projected to rise about 15% by 2029 — from 0.15 in 2024 to a central estimate of 0.17 (95% range 0.10–0.25). A 5-year backtest shows a typical error of ±46.6%, with 80% of held-out values landing inside the 95% band.

+15%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 →
0.17Projected 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 →
0.10–0.2595% 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 →
±46.6%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, Bald Eagle in California is projected to rise about 15% by 2029 — from 0.15 in 2024 to a central estimate of 0.17 (95% range 0.10–0.25). A 5-year backtest shows a typical error of ±46.6%, with 80% of held-out values landing inside the 95% band.19722029
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 →
20250.160.090.23
20260.160.090.24
20270.170.090.24
20280.170.100.25
20290.170.100.25

Bald Eagle Survey Routes in California

Routes recording Bald Eagle 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 →
Horse Creek520181972
Davis Creek420231978
Woodfords420222021
Iron Gate320191992
Lake Berryessa320242024
Red Bluff220181992
Creston220192015
Whiskeytown220062002
Likely220241992
Crowder Flat220072005
Sattley220242024
Oroville220122012
Longvale220232018
Dorris220181994
Macdoel220191975
Chilcoot220232023
Strawberry220122002
Bodega Bay220182017
Ingalls219971997
S Catalina220132013
Poloma220172014
Adelaida220242022
Nubieber120072000
Crescent Cty120012001
Holmes120221973

Bald Eagle Population Trend in Other States

alabamaalaskaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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