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

Western Bluebird In Coastal California

All regionsCoastal CaliforniaForest birds

Western Bluebird in Coastal California has held roughly steady: up 4% on the route-weighted index since 1970.

+4%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 →
108Routes 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 Western Bluebird in Coastal California. See the full index history below.

Western Bluebird In Coastal California Population Forecast

If the recent trend holds, Western Bluebird in Coastal California is projected to rise about 19% by 2030 — from 5.5 in 2025 to a central estimate of 6.6 (95% range 4.3–8.9). A 5-year backtest shows a typical error of ±35.9%, with 80% of held-out values landing inside the 95% band.

+19%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 →
6.6Projected 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 →
4.3–8.995% 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 →
±35.9%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 Bluebird in Coastal California is projected to rise about 19% by 2030 — from 5.5 in 2025 to a central estimate of 6.6 (95% range 4.3–8.9). A 5-year backtest shows a typical error of ±35.9%, 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 →
20266.54.28.8
20276.54.28.8
20286.54.28.8
20296.54.28.9
20306.64.38.9

Routes In Coastal California

Routes recording Western Bluebird 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 →
Tres Pinos 2CALIFORNIA572011
Mt Pinos 2CALIFORNIA312024
ValyermoCALIFORNIA252019
Cal Hot SpgsCALIFORNIA252019
White RiverCALIFORNIA221992
Gold HillCALIFORNIA212025
ReddingCALIFORNIA211983
Glen EllenCALIFORNIA202004
AdelaidaCALIFORNIA182025
Carmel ValCALIFORNIA142025
JacksonCALIFORNIA141992
LockwoodCALIFORNIA142025
Yokohl ValCALIFORNIA131997
Big BearCALIFORNIA121986
FolsomCALIFORNIA122025
TujungaCALIFORNIA122021
Lake HemetCALIFORNIA111986
PolomaCALIFORNIA112024
San Benito Mtn.CALIFORNIA112009
SisquocCALIFORNIA102014
Red BluffCALIFORNIA92025
CohassetCALIFORNIA92025
Mesa GrandeCALIFORNIA92025
Lockwood ValCALIFORNIA92019
Yolla BollyCALIFORNIA92025

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