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

Rufous-crowned Sparrow In Coastal California

All regionsCoastal CaliforniaArid-land birds

Rufous-crowned Sparrow in Coastal California has surged: up 522% on the route-weighted index since 1972.

+522%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 →
63Routes 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 →
55YearsYears 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 522% on the route-weighted index since 1972.

Rufous-crowned Sparrow In Coastal California Population Forecast

If the recent trend holds, Rufous-crowned Sparrow in Coastal California is projected to stay roughly flat through 2030, near 0.98 (95% range 0.48–1.5). A 5-year backtest shows a typical error of ±36.8%, with 40% of held-out values landing inside the 95% band.

+6%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 →
0.98Projected 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 →
0.48–1.595% 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 →
±36.8%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 stay roughly flat through 2030, near 0.98 (95% range 0.48–1.5). A 5-year backtest shows a typical error of ±36.8%, with 40% of held-out values landing inside the 95% band.19702030
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 →
20260.930.441.4
20270.940.451.4
20280.950.461.4
20290.960.471.5
20300.980.481.5

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 MtnCALIFORNIA192025
Santa Cruz ICALIFORNIA181988
Angelus OaksCALIFORNIA92005
GreenfieldCALIFORNIA72025
Red BluffCALIFORNIA51995
Lake SuccessCALIFORNIA51972
PowayCALIFORNIA51980
SangerCALIFORNIA42023
Hough SpringsCALIFORNIA42007
Orange CoveCALIFORNIA32012
Lake CachumaCALIFORNIA32016
Lake Hemet 2CALIFORNIA32014
JofeganCALIFORNIA32023
RumseyCALIFORNIA22008
Tres PinosCALIFORNIA22002
MorenoCALIFORNIA22025
El ToroCALIFORNIA21987
Lake BerryessaCALIFORNIA22025
Cuyamaca PkCALIFORNIA22025
White RiverCALIFORNIA21992
MoragaCALIFORNIA21986
OnealsCALIFORNIA22019
Cal Hot SpgsCALIFORNIA22016
Yokohl ValCALIFORNIA11997
Santa YnezCALIFORNIA12018

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