BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Lesser Goldfinch In Coastal California

All regionsCoastal CaliforniaGeneralists

Lesser Goldfinch in Coastal California has surged: up 75% on the route-weighted index since 1970.

+75%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 →
116Routes 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 →
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 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 →

Lesser Goldfinch has surged in Coastal California: up 75% on the route-weighted index since 1970.

Lesser Goldfinch In Coastal California Population Forecast

If the recent trend holds, Lesser Goldfinch in Coastal California is projected to stay roughly flat through 2029, near 15 (95% range 10–20). A 5-year backtest shows a typical error of ±20.8%, with 100% of held-out values landing inside the 95% band.

-6%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 →
15Projected 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 →
10–2095% 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 →
±20.8%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, Lesser Goldfinch in Coastal California is projected to stay roughly flat through 2029, near 15 (95% range 10–20). A 5-year backtest shows a typical error of ±20.8%, 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 →
2025159.920
20261510.020
2027151020
2028151020
2029151020

Routes In Coastal California

Routes recording Lesser 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 →
Jofegan 2CALIFORNIA632024
CohassetCALIFORNIA582024
Gold HillCALIFORNIA582024
FolsomCALIFORNIA562024
Harbor Lake 2CALIFORNIA412024
FallsvaleCALIFORNIA401981
Bartlett SpsCALIFORNIA382018
Mt LagunaCALIFORNIA371987
RumseyCALIFORNIA362008
AuburnCALIFORNIA351980
Red BluffCALIFORNIA332024
Elsinore MtnCALIFORNIA332024
Cuyamaca PkCALIFORNIA312024
ColmaCALIFORNIA301972
PowayCALIFORNIA301980
San YsidroCALIFORNIA282019
Point ReyesCALIFORNIA282023
White RiverCALIFORNIA271992
MorenoCALIFORNIA252024
LockwoodCALIFORNIA242024
Tres Pinos 2CALIFORNIA242011
OrovilleCALIFORNIA232024
PenningtonCALIFORNIA222024
CopperopolisCALIFORNIA222024
TujungaCALIFORNIA212021

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