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

Western Tanager In Coastal California

All regionsCoastal CaliforniaGeneralists

Western Tanager in Coastal California has edged down: down 22% on the route-weighted index since 1970.

-22%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 →
85Routes 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 Western Tanager in Coastal California. See the full index history below.

Forecast

If the recent trend holds, Western Tanager in Coastal California is projected to rise about 47% by 2029 — from 1.4 in 2024 to a central estimate of 2.1 (95% range 0.77–3.5). A 5-year backtest shows a typical error of ±34.7%, with 100% of held-out values landing inside the 95% band.

+47%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 →
2.1Projected 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 →
0.77–3.595% 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 →
±34.7%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, Western Tanager in Coastal California is projected to rise about 47% by 2029 — from 1.4 in 2024 to a central estimate of 2.1 (95% range 0.77–3.5). A 5-year backtest shows a typical error of ±34.7%, 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 →
20252.20.793.5
20262.10.793.5
20272.10.783.5
20282.10.773.5
20292.10.773.5

Routes In Coastal California

Routes recording Western Tanager 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 →
Hough SpringsCALIFORNIA382007
StonyfordCALIFORNIA312018
FallsvaleCALIFORNIA241981
CohassetCALIFORNIA232024
JacksonCALIFORNIA161984
Mt BaldyCALIFORNIA152024
Bartlett SpsCALIFORNIA142018
ValyermoCALIFORNIA132019
Angelus OaksCALIFORNIA122017
Green ValleyCALIFORNIA112023
TehamaCALIFORNIA102022
TomheadCALIFORNIA102011
CalpellaCALIFORNIA81986
RumseyCALIFORNIA82008
Point ReyesCALIFORNIA82008
White RiverCALIFORNIA71992
Santa YnezCALIFORNIA62014
Lake HemetCALIFORNIA61986
Red BluffCALIFORNIA52024
Lake SuccessCALIFORNIA51996
Big BearCALIFORNIA51986
ColmaCALIFORNIA41968
FolsomCALIFORNIA42023
Mt LagunaCALIFORNIA41987
Gold HillCALIFORNIA42024

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