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

Savannah Sparrow Population Trend in California

All statesGrassland birds

Savannah Sparrow in California has surged: up 107% on the route-weighted index since 1970.

+107%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 →
77Routes 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 Savannah 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 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 →

Savannah Sparrow has surged in California: up 107% on the route-weighted index since 1970.

Savannah Sparrow Population Forecast in California

If the recent trend holds, Savannah Sparrow in California is projected to rise about 70% by 2030 — from 0.72 in 2025 to a central estimate of 1.2 (95% range 0.21–2.2). A 5-year backtest shows a typical error of ±269.7%, with 40% of held-out values landing inside the 95% band.

+70%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 →
1.2Projected 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 →
0.21–2.295% 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 →
±269.7%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, Savannah Sparrow in California is projected to rise about 70% by 2030 — from 0.72 in 2025 to a central estimate of 1.2 (95% range 0.21–2.2). A 5-year backtest shows a typical error of ±269.7%, with 40% 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 →
20261.20.202.2
20271.20.202.2
20281.20.212.2
20291.20.212.2
20301.20.212.2

Savannah Sparrow Survey Routes in California

Routes recording Savannah 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 →
Poway3819801973
Crowley Lake3820251972
Dorris3820191972
Hughson3019771977
Macdoel1320191972
Clear Lk Res1220181977
Rio Dell1020121972
Orland1019931993
Oilfields820051973
Yreka820191973
Goumaz820111997
Crescent Cty720251975
Honeydew720171968
Ingalls620001973
Likely520251972
Ora Loma519761976
Nubieber420181970
San Ysidro419761973
Bodega Bay420191973
Collegeville319721972
Fairfax319731973
Carrizo Pln320231993
Glenn319711971
Sattley320251972
Honey Lake320081994

Savannah Sparrow Population Trend in Other States

alaskaarizonacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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