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

California Thrasher In Coastal California

All regionsCoastal CaliforniaArid-land birds

California Thrasher in Coastal California has increased: up 32% on the route-weighted index since 1970.

+32%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 →
84Routes 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 →

No notable trend signals for California Thrasher in Coastal California. See the full index history below.

California Thrasher In Coastal California Population Forecast

If the recent trend holds, California Thrasher in Coastal California is projected to fall about 41% by 2030 — from 4.0 in 2025 to a central estimate of 2.4 (95% range 0.67–4.0). A 5-year backtest shows a typical error of ±36.1%, with 80% of held-out values landing inside the 95% band.

-41%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 →
2.4Projected 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 →
0.67–4.095% 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 →
±36.1%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, California Thrasher in Coastal California is projected to fall about 41% by 2030 — from 4.0 in 2025 to a central estimate of 2.4 (95% range 0.67–4.0). A 5-year backtest shows a typical error of ±36.1%, with 80% 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 →
20262.40.694.1
20272.40.684.1
20282.40.684.1
20292.40.674.1
20302.40.674.0

Routes In Coastal California

Routes recording California Thrasher 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 MtnCALIFORNIA542025
Lake CachumaCALIFORNIA372016
Cuyamaca PkCALIFORNIA332025
RumseyCALIFORNIA192008
Mt BaldyCALIFORNIA182024
JacumbaCALIFORNIA172025
Oak GroveCALIFORNIA122025
PowayCALIFORNIA121980
Lockwood ValCALIFORNIA112019
AnzaCALIFORNIA112004
ColmaCALIFORNIA101971
Cleveland Nf 2CALIFORNIA102022
Anza 2CALIFORNIA92025
FallsvaleCALIFORNIA81981
Elizabeth LkCALIFORNIA72016
Hough SpringsCALIFORNIA72007
TomheadCALIFORNIA62011
StonyfordCALIFORNIA62018
Foster ParkCALIFORNIA51994
Green ValleyCALIFORNIA52023
GreenfieldCALIFORNIA52025
Tres Pinos 2CALIFORNIA52011
TujungaCALIFORNIA42018
Mesa GrandeCALIFORNIA42025
Lake HemetCALIFORNIA41986

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