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

Chipping Sparrow Population Trend in California

All statesForest birds

Chipping Sparrow in California has fallen sharply: down 51% on the route-weighted index since 1970.

-51%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 →
177Routes 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 Chipping 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 →

long arc declinecomputed 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 →

Chipping Sparrow has fallen sharply in California: down 51% on the route-weighted index since 1970.

Chipping Sparrow Population Forecast in California

If the recent trend holds, Chipping Sparrow in California is projected to stay roughly flat through 2030, near 2.3 (95% range 0.83–3.7). A 5-year backtest shows a typical error of ±38.4%, with 100% of held-out values landing inside the 95% band.

-6%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 →
2.3Projected 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 →
0.83–3.795% 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 →
±38.4%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, Chipping Sparrow in California is projected to stay roughly flat through 2030, near 2.3 (95% range 0.83–3.7). A 5-year backtest shows a typical error of ±38.4%, 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 →
20262.40.973.8
20272.40.943.8
20282.30.903.8
20292.30.873.7
20302.30.833.7

Chipping Sparrow Survey Routes in California

Routes recording Chipping 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 →
Santa Cruz I5719881988
Goumaz4620111997
Macdoel3220191972
S Catalina2520251988
Chester2520171997
Eagle Lake2220251969
Last Chance2220191993
Alderpoint2020121974
Crowder Flat1920192002
Westville1620251971
Hackamore1620102000
Pollock Pines1620251997
Martins Fy1520091976
Mccloud1420211973
Chilcoot1320241998
Ingalls1220251973
Riverton1220251973
Tuolumne Grove1120251972
Pine Mountain1120171997
White River1019921972
Tahoe Nf1019941987
Meadow Valley1020251999
Medicine Mtn.1020212000
Cohasset920251974
Tionesta920211997

Chipping Sparrow Population Trend in Other States

alabamaalaskaarizonaarkansascoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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