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

Rufous-crowned Sparrow In Coastal California

All regionsCoastal CaliforniaGeneralists

Rufous-crowned Sparrow in Coastal California has surged: up 620% on the route-weighted index since 1972.

+620%Since 1972TrendPercent 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 →
62Routes 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 →
54YearsYears 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 →

Rufous-crowned Sparrow has surged in Coastal California: up 620% on the route-weighted index since 1972.

Forecast

If the recent trend holds, Rufous-crowned Sparrow in Coastal California is projected to fall about 24% by 2029 — from 1.3 in 2024 to a central estimate of 0.96 (95% range 0.47–1.5). A 5-year backtest shows a typical error of ±43.5%, with 40% of held-out values landing inside the 95% band.

-24%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 →
0.96Projected 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 →
0.47–1.595% 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 →
±43.5%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, Rufous-crowned Sparrow in Coastal California is projected to fall about 24% by 2029 — from 1.3 in 2024 to a central estimate of 0.96 (95% range 0.47–1.5). A 5-year backtest shows a typical error of ±43.5%, with 40% of held-out values landing inside the 95% band.19702029
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 →
20250.920.421.4
20260.930.431.4
20270.940.441.4
20280.950.451.5
20290.960.471.5

Routes In Coastal California

Routes recording Rufous-crowned 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 →
Elsinore MtnCALIFORNIA262024
Santa Cruz ICALIFORNIA181988
Cuyamaca PkCALIFORNIA122021
MorenoCALIFORNIA112024
GreenfieldCALIFORNIA92024
Angelus OaksCALIFORNIA92005
Red BluffCALIFORNIA51995
Lake SuccessCALIFORNIA51972
PowayCALIFORNIA51980
Oak GroveCALIFORNIA42024
SangerCALIFORNIA42023
CoyoteCALIFORNIA42024
Hough SpringsCALIFORNIA42007
Orange CoveCALIFORNIA32012
Lake CachumaCALIFORNIA32016
Lake Hemet 2CALIFORNIA32014
JofeganCALIFORNIA32023
RumseyCALIFORNIA22008
Tres PinosCALIFORNIA22002
El ToroCALIFORNIA21987
White RiverCALIFORNIA21992
MoragaCALIFORNIA21986
OnealsCALIFORNIA22019
Cal Hot SpgsCALIFORNIA22016
Yokohl ValCALIFORNIA11997

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