BirdAnalyst
Species · California · BBS 2025 Release · 1966–2024

Bushtit Population Trend in California

All statesGeneralists

Bushtit in California has declined: down 49% on the route-weighted index since 1970.

-49%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 →
195Routes In StateSurvey 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 Bushtit Trends in CaliforniaNotable 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 Bushtit in California. See the full index history below.

Bushtit Population Forecast in California

If the recent trend holds, Bushtit in California is projected to fall about 21% by 2029 — from 3.9 in 2024 to a central estimate of 3.1 (95% range 0.89–5.3). A 5-year backtest shows a typical error of ±27%, with 100% of held-out values landing inside the 95% band.

-21%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 →
3.1Projected 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 →
0.89–5.395% 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 →
±27%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, Bushtit in California is projected to fall about 21% by 2029 — from 3.9 in 2024 to a central estimate of 3.1 (95% range 0.89–5.3). A 5-year backtest shows a typical error of ±27%, 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 →
20253.21.15.4
20263.21.05.4
20273.20.975.4
20283.10.935.3
20293.10.895.3

Bushtit Survey Routes in California

Routes recording Bushtit in 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 →
Poway9619801973
Morro Bay8120191973
Foster Park5219941968
Jofegan 24720242024
Santa Ynez3520191969
Auburn3519801969
Jackson3019921972
Elsinore Mtn2820241970
Mt Pinos 22620212010
Coyote2620241972
Adelaida2520241970
Colma2419721968
Orland2120221988
Moraga1920241972
Orange Cove1720161972
Greenhorn Mt1720061973
Stonyford1620182016
San Ysidro1520191973
Sanger1520242011
Higgins Corn1520241975
Coulterville1520191997
Yokohl Val1419971972
Fairfax1420241972
Carmel Val1420241974
Cuyamaca Pk1420241970

Bushtit Population Trend in Other States

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