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

Song Sparrow Population Trend in California

All statesForest birds

Song Sparrow in California has increased: up 45% on the route-weighted index since 1970.

+45%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 →
206Routes 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 Song Sparrow 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 Song Sparrow in California. See the full index history below.

Song Sparrow Population Forecast in California

If the recent trend holds, Song Sparrow in California is projected to stay roughly flat through 2030, near 5.5 (95% range 3.4–7.6). A 5-year backtest shows a typical error of ±47.7%, with 60% 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 →
5.5Projected 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 →
3.4–7.695% 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 →
±47.7%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, Song Sparrow in California is projected to stay roughly flat through 2030, near 5.5 (95% range 3.4–7.6). A 5-year backtest shows a typical error of ±47.7%, with 60% 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 →
20265.53.47.6
20275.53.47.6
20285.53.47.6
20295.53.47.6
20305.53.47.6

Song Sparrow Survey Routes in California

Routes recording Song Sparrow 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 →
Dorris8420191976
Horse Creek5420191970
Ora Loma4320251972
Point Reyes3220251970
Crescent Cty3120251972
Rio Dell3120121972
Santa Cruz I3019881988
Staten Is.3020251994
Honeydew2920171968
Navarro2920111972
Jofegan 22820252024
Redwood N.P.2520101995
Harbor Lake 22420242014
Holmes2320251968
Pescadero2320251992
Cp. Pendleton2220041970
Genesee2220241972
Fish Rock2120141968
Arvin2020221971
Sisquoc1920141970
Paxton1820251998
Lake Berryessa1720252023
Poway1619801973
Last Chance1520191993
Moreno1420251974

Song Sparrow Population Trend in Other States

alabamaalaskaarizonaarkansascoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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