BirdAnalyst
Species · BCR 32 · BBS 2026 Release · 1966–2025

American Goldfinch In Coastal California

All regionsCoastal CaliforniaForest birds

American Goldfinch in Coastal California has surged: up 94% on the route-weighted index since 1970.

+94%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 →
86Routes In RegionSurvey 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 SignalsNotable 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 →

American Goldfinch has surged in Coastal California: up 94% on the route-weighted index since 1970.

American Goldfinch In Coastal California Population Forecast

If the recent trend holds, American Goldfinch in Coastal California is projected to stay roughly flat through 2030, near 4.5 (95% range 1.4–7.5). A 5-year backtest shows a typical error of ±57.3%, with 100% of held-out values landing inside the 95% band.

+2%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 →
4.5Projected 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 →
1.4–7.595% 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 →
±57.3%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 Coastal California is projected to stay roughly flat through 2030, near 4.5 (95% range 1.4–7.5). A 5-year backtest shows a typical error of ±57.3%, 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 →
20264.31.27.3
20274.31.37.4
20284.41.37.4
20294.41.47.5
20304.51.47.5

Routes In Coastal California

Routes recording American Goldfinch in Coastal 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 SuccessCALIFORNIA421978
ZamoraCALIFORNIA382025
Collegeville 2CALIFORNIA312023
CohassetCALIFORNIA292025
OrovilleCALIFORNIA282025
WestleyCALIFORNIA202025
AtwaterCALIFORNIA162012
Cp. PendletonCALIFORNIA132004
Ora LomaCALIFORNIA132025
Tres PinosCALIFORNIA101996
Mt LagunaCALIFORNIA101986
HughsonCALIFORNIA92025
Lake Hemet 2CALIFORNIA91993
PenningtonCALIFORNIA82025
AuburnCALIFORNIA81980
Lockwood ValCALIFORNIA82008
Cuyamaca PkCALIFORNIA81975
Mark WestCALIFORNIA72025
Glen EllenCALIFORNIA72004
HollisterCALIFORNIA62011
Morro BayCALIFORNIA62018
JacumbaCALIFORNIA61976
Tracy 2CALIFORNIA62024
Harbor Lake 2CALIFORNIA52017
Red BluffCALIFORNIA42025

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