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

Lesser Goldfinch Population Trend in California

All statesGeneralists

Lesser Goldfinch in California has increased: up 38% on the route-weighted index since 1970.

+38%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 →
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 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 fall about 14% by 2029 — from 9.8 in 2024 to a central estimate of 8.4 (95% range 5.8–11). A 5-year backtest shows a typical error of ±15%, with 100% of held-out values landing inside the 95% band.

-14%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 →
8.4Projected 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 →
5.8–1195% 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 →
±15%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 fall about 14% by 2029 — from 9.8 in 2024 to a central estimate of 8.4 (95% range 5.8–11). A 5-year backtest shows a typical error of ±15%, 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 →
20258.35.711
20268.45.711
20278.45.711
20288.45.811
20298.45.811

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 →
Jofegan 26320242024
Cohasset5820241972
Gold Hill5820241975
Folsom5620241984
Iron Gate5120191988
Harbor Lake 24120242014
Fallsvale4019811970
Bartlett Sps3820181972
Higgins Corn3820241974
Mt Laguna3719871970
Rumsey3620081969
Auburn3519801969
Macdoel3420191972
Red Bluff3320241968
Elsinore Mtn3320241970
Cuyamaca Pk3120241970
Colma3019721968
Poway3019801973
Bass Lake2920191972
San Ysidro2820191973
Point Reyes2820231970
Blythe2720031977
White River2719921972
Moreno2520241973
Lockwood2420241972

Lesser Goldfinch Population Trend in Other States

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