BirdAnalyst
Species · California · BBS 2026 Release · 1966–2025

Lesser Goldfinch Population Trend in California

All statesForest birds

Lesser Goldfinch in California has increased: up 50% on the route-weighted index since 1970.

+50%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 →
228Routes 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 →
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 Lesser 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 Lesser Goldfinch in California. See the full index history below.

Lesser Goldfinch Population Forecast in California

If the recent trend holds, Lesser Goldfinch in California is projected to stay roughly flat through 2030, near 8.5 (95% range 5.9–11). A 5-year backtest shows a typical error of ±12.2%, with 100% of held-out values landing inside the 95% band.

-8%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 →
8.5Projected 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 →
5.9–1195% 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 →
±12.2%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 California is projected to stay roughly flat through 2030, near 8.5 (95% range 5.9–11). A 5-year backtest shows a typical error of ±12.2%, 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 →
20268.45.811
20278.45.811
20288.55.811
20298.55.911
20308.55.911

Lesser Goldfinch Survey Routes in California

Routes recording Lesser 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 →
Coyote5420251972
Jofegan 25220252024
Iron Gate5120191988
Elsinore Mtn4520251970
Folsom4220251984
Moraga4220251972
Harbor Lake 24120242014
Fallsvale4019811970
Bartlett Sps3820181972
Mt Laguna3719871970
Rumsey3620081969
Auburn3519801969
Macdoel3420191972
Pennington3020251971
Colma3019721968
Poway3019801973
Bass Lake2920191972
San Ysidro2820191973
Blythe2720031977
White River2719921972
Yolla Bolly2720251973
Moreno2620251973
Lockwood2520251972
Tres Pinos 22420112005
Red Bluff2320251968

Lesser Goldfinch Population Trend in Other States

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