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

Swainson's Thrush In Coastal California

All regionsCoastal CaliforniaForest birds

Swainson's Thrush in Coastal California has increased: up 29% on the route-weighted index since 1970.

+29%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 →
47Routes 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 Swainson's Thrush in Coastal California. See the full index history below.

Forecast

If the recent trend holds, Swainson's Thrush in Coastal California is projected to rise about 141% by 2029 — from 1.1 in 2024 to a central estimate of 2.6 (95% range 1.5–3.6). A 5-year backtest shows a typical error of ±64.3%, with 80% of held-out values landing inside the 95% band.

+141%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 →
2.6Projected 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 →
1.5–3.695% 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 →
±64.3%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, Swainson's Thrush in Coastal California is projected to rise about 141% by 2029 — from 1.1 in 2024 to a central estimate of 2.6 (95% range 1.5–3.6). A 5-year backtest shows a typical error of ±64.3%, with 80% 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 →
20252.51.43.5
20262.51.43.6
20272.51.43.6
20282.51.53.6
20292.61.53.6

Routes In Coastal California

Routes recording Swainson's Thrush 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 →
Point ReyesCALIFORNIA592023
PescaderoCALIFORNIA302024
FairfaxCALIFORNIA162024
Morro BayCALIFORNIA62019
CalpellaCALIFORNIA51981
BakersfieldCALIFORNIA51970
Santa YnezCALIFORNIA51997
Cuyamaca PkCALIFORNIA41972
MoragaCALIFORNIA32010
Mark WestCALIFORNIA32024
Lake Hemet 2CALIFORNIA31994
FolsomCALIFORNIA22009
TujungaCALIFORNIA21977
Mt LagunaCALIFORNIA21972
JacksonCALIFORNIA21976
Bartlett SpsCALIFORNIA22014
Cal Hot SpgsCALIFORNIA21993
ColmaCALIFORNIA11971
CollegevilleCALIFORNIA11973
ParkfieldCALIFORNIA11977
Foster ParkCALIFORNIA11993
Harbor LakeCALIFORNIA11991
Oak GroveCALIFORNIA11978
Big BearCALIFORNIA11980
S CatalinaCALIFORNIA11998

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