BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

House Sparrow In Coastal California

All regionsCoastal CaliforniaGeneralists

House Sparrow in Coastal California has fallen sharply: down 57% on the route-weighted index since 1970.

-57%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 →
111Routes 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 →
56YearsYears 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 57% on the route-weighted index since 1970.

Forecast

If the recent trend holds, House Sparrow in Coastal California is projected to fall about 37% by 2029 — from 23 in 2024 to a central estimate of 15 (95% range 0.00–33). A 5-year backtest shows a typical error of ±36.6%, with 100% of held-out values landing inside the 95% band.

-37%Change by 2029TrendPercent 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 2029 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 →
±36.6%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 37% by 2029 — from 23 in 2024 to a central estimate of 15 (95% range 0.00–33). A 5-year backtest shows a typical error of ±36.6%, with 100% of held-out values landing inside the 95% band.19682029
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 →
2025170.0035
2026170.0035
2027160.0034
2028150.0033
2029150.0033

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
OrovilleCALIFORNIA1662024
TiptonCALIFORNIA1531997
GlennCALIFORNIA1232023
GravesboroCALIFORNIA1111995
MorenoCALIFORNIA1102024
ShafterCALIFORNIA941989
ReddingCALIFORNIA851983
LivermoreCALIFORNIA831991
Ora LomaCALIFORNIA822024
CaruthersCALIFORNIA781987
San YsidroCALIFORNIA752019
HughsonCALIFORNIA702024
AthloneCALIFORNIA682007
CollegevilleCALIFORNIA672004
WestleyCALIFORNIA672024
Buena VistaCALIFORNIA592019
AuburnCALIFORNIA581980
OilfieldsCALIFORNIA572013
Harbor LakeCALIFORNIA561991
Collegeville 2CALIFORNIA542023
Hollister 2CALIFORNIA512024
GreenfieldCALIFORNIA502024
PenningtonCALIFORNIA492024

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.