BirdAnalyst
Species · BCR 32 · BBS 2026 Release · 1966–2025

Song Sparrow In Coastal California

All regionsCoastal CaliforniaForest birds

Song Sparrow in Coastal California has surged: up 182% on the route-weighted index since 1970.

+182%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 →
109Routes In RegionSurvey 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 SignalsNotable 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 →

Song Sparrow has surged in Coastal California: up 182% on the route-weighted index since 1970.

Song Sparrow In Coastal California Population Forecast

If the recent trend holds, Song Sparrow in Coastal California is projected to fall about 16% by 2030 — from 7.3 in 2025 to a central estimate of 6.1 (95% range 3.1–9.1). A 5-year backtest shows a typical error of ±29.9%, with 100% of held-out values landing inside the 95% band.

-16%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 →
6.1Projected 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 →
3.1–9.195% 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 →
±29.9%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 Coastal California is projected to fall about 16% by 2030 — from 7.3 in 2025 to a central estimate of 6.1 (95% range 3.1–9.1). A 5-year backtest shows a typical error of ±29.9%, 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 →
20266.03.09.1
20276.13.19.1
20286.13.19.1
20296.13.19.1
20306.13.19.1

Routes In Coastal California

Routes recording Song Sparrow in Coastal 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 →
Ora LomaCALIFORNIA432025
Point ReyesCALIFORNIA322025
Santa Cruz ICALIFORNIA301988
Staten Is.CALIFORNIA302025
Jofegan 2CALIFORNIA282025
Harbor Lake 2CALIFORNIA242024
PescaderoCALIFORNIA232025
Cp. PendletonCALIFORNIA222004
ArvinCALIFORNIA202022
SisquocCALIFORNIA192014
Lake BerryessaCALIFORNIA172025
PowayCALIFORNIA161980
MorenoCALIFORNIA142025
GreenfieldCALIFORNIA142025
El ToroCALIFORNIA131999
CoyoteCALIFORNIA132025
ColmaCALIFORNIA121972
FairfaxCALIFORNIA122024
Carmel ValCALIFORNIA122025
RumseyCALIFORNIA112008
FallsvaleCALIFORNIA111981
Mark WestCALIFORNIA112025
Cuyamaca PkCALIFORNIA102025
LockwoodCALIFORNIA102025
Harbor LakeCALIFORNIA91991

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