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

California Thrasher In Coastal California

All regionsCoastal CaliforniaGeneralists

California Thrasher in Coastal California has edged up: up 15% on the route-weighted index since 1970.

+15%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 →
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 →

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 34% by 2029 — from 3.4 in 2024 to a central estimate of 2.2 (95% range 0.58–3.9). A 5-year backtest shows a typical error of ±34.1%, with 100% of held-out values landing inside the 95% band.

-34%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 →
2.2Projected 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 →
0.58–3.995% 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 →
±34.1%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 34% by 2029 — from 3.4 in 2024 to a central estimate of 2.2 (95% range 0.58–3.9). A 5-year backtest shows a typical error of ±34.1%, 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 →
20252.30.613.9
20262.30.603.9
20272.20.593.9
20282.20.593.9
20292.20.583.9

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 MtnCALIFORNIA412024
Lake CachumaCALIFORNIA372016
Cuyamaca PkCALIFORNIA272024
RumseyCALIFORNIA192008
Mt BaldyCALIFORNIA182024
Oak GroveCALIFORNIA162024
PowayCALIFORNIA121980
Lockwood ValCALIFORNIA112019
AnzaCALIFORNIA112004
ColmaCALIFORNIA101971
JacumbaCALIFORNIA102024
Anza 2CALIFORNIA102024
Cleveland Nf 2CALIFORNIA102022
FallsvaleCALIFORNIA81981
Elizabeth LkCALIFORNIA72016
Yolla BollyCALIFORNIA72024
Hough SpringsCALIFORNIA72007
FolsomCALIFORNIA62024
Mesa GrandeCALIFORNIA62024
GreenfieldCALIFORNIA62024
TomheadCALIFORNIA62011
StonyfordCALIFORNIA62018
Foster ParkCALIFORNIA51994
Green ValleyCALIFORNIA52023
Tres Pinos 2CALIFORNIA52011

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