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

House Sparrow In Coastal California

All regionsCoastal CaliforniaGeneralists

House Sparrow in Coastal California has fallen sharply: down 59% on the route-weighted index since 1970.

-59%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 →
112Routes 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 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 →

House Sparrow has fallen sharply in Coastal California: down 59% on the route-weighted index since 1970.

House Sparrow In Coastal California Population Forecast

If the recent trend holds, House Sparrow in Coastal California is projected to fall about 43% by 2030 — from 26 in 2025 to a central estimate of 15 (95% range 0.00–33). A 5-year backtest shows a typical error of ±35.9%, with 100% of held-out values landing inside the 95% band.

-43%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 →
15Projected 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 →
0.00–3395% 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 →
±35.9%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, House Sparrow in Coastal California is projected to fall about 43% by 2030 — from 26 in 2025 to a central estimate of 15 (95% range 0.00–33). A 5-year backtest shows a typical error of ±35.9%, 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 →
2026170.0035
2027160.0035
2028160.0034
2029150.0033
2030150.0033

Routes In Coastal California

Routes recording House 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 →
AtwaterCALIFORNIA7552012
OrlandCALIFORNIA2082022
TiptonCALIFORNIA1531997
MorenoCALIFORNIA1352025
GravesboroCALIFORNIA1111995
ShafterCALIFORNIA941989
ReddingCALIFORNIA851983
LivermoreCALIFORNIA831991
CaruthersCALIFORNIA781987
San YsidroCALIFORNIA752019
OrovilleCALIFORNIA732025
AthloneCALIFORNIA682007
CollegevilleCALIFORNIA672004
Ora LomaCALIFORNIA672025
PenningtonCALIFORNIA652025
GlennCALIFORNIA632025
Buena VistaCALIFORNIA592019
AuburnCALIFORNIA581980
HughsonCALIFORNIA572025
OilfieldsCALIFORNIA572013
Harbor LakeCALIFORNIA561991
WestleyCALIFORNIA562025
Yolla BollyCALIFORNIA542025
Collegeville 2CALIFORNIA542023
LockwoodCALIFORNIA532025

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