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

Lesser Goldfinch In Coastal California

All regionsCoastal CaliforniaForest birds

Lesser Goldfinch in Coastal California has surged: up 99% on the route-weighted index since 1970.

+99%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 →
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 →

Lesser Goldfinch has surged in Coastal California: up 99% 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 fall about 11% by 2030 — from 17 in 2025 to a central estimate of 15 (95% range 11–20). A 5-year backtest shows a typical error of ±16.2%, with 100% of held-out values landing inside the 95% band.

-11%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 →
15Projected 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 →
11–2095% 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 →
±16.2%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 fall about 11% by 2030 — from 17 in 2025 to a central estimate of 15 (95% range 11–20). A 5-year backtest shows a typical error of ±16.2%, 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 →
2026151020
2027151020
2028151020
2029151020
2030151120

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 →
CoyoteCALIFORNIA542025
Jofegan 2CALIFORNIA522025
Elsinore MtnCALIFORNIA452025
FolsomCALIFORNIA422025
MoragaCALIFORNIA422025
Harbor Lake 2CALIFORNIA412024
FallsvaleCALIFORNIA401981
Bartlett SpsCALIFORNIA382018
Mt LagunaCALIFORNIA371987
RumseyCALIFORNIA362008
AuburnCALIFORNIA351980
PenningtonCALIFORNIA302025
ColmaCALIFORNIA301972
PowayCALIFORNIA301980
San YsidroCALIFORNIA282019
White RiverCALIFORNIA271992
Yolla BollyCALIFORNIA272025
MorenoCALIFORNIA262025
LockwoodCALIFORNIA252025
Tres Pinos 2CALIFORNIA242011
Red BluffCALIFORNIA232025
Cuyamaca PkCALIFORNIA232025
Glen Ellen 3CALIFORNIA232025
CohassetCALIFORNIA222025
CopperopolisCALIFORNIA222024

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