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

American Goldfinch Population Trend in California

All statesGeneralists

American Goldfinch in California has held roughly steady: down 10% on the route-weighted index since 1970.

-10%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 →
146Routes 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 Goldfinch 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 American Goldfinch in California. See the full index history below.

American Goldfinch Population Forecast in California

If the recent trend holds, American Goldfinch in California is projected to rise about 37% by 2029 — from 1.7 in 2024 to a central estimate of 2.3 (95% range 0.88–3.8). A 5-year backtest shows a typical error of ±70.3%, with 100% of held-out values landing inside the 95% band.

+37%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 →
2.3Projected 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 →
0.88–3.895% 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 →
±70.3%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 Goldfinch in California is projected to rise about 37% by 2029 — from 1.7 in 2024 to a central estimate of 2.3 (95% range 0.88–3.8). A 5-year backtest shows a typical error of ±70.3%, 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 →
20252.30.843.7
20262.30.853.7
20272.30.863.7
20282.30.873.7
20292.30.883.8

American Goldfinch Survey Routes in California

Routes recording American Goldfinch 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 →
Lake Success4219781972
Oroville3520241972
Westley3320241976
Collegeville 23120232007
Honeydew2220171968
Rio Dell2220121972
Atwater1620122003
Dorris1520192001
Zamora1520241975
Pennington1420241971
Cp. Pendleton1320041971
Fish Rock1220141968
Redwood N.P.1220101995
Crescent Cty1120241972
Hughson1020241968
Tres Pinos1019961973
Mt Laguna1019861974
Lake Hemet 2919931992
Auburn819801969
Lockwood Val820082008
Cuyamaca Pk819751973
Glenn820231975
Greenhorn Mt719801974
Glen Ellen720041987
Red Bluff620221968

American Goldfinch Population Trend in Other States

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

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