BirdAnalyst
Species · California · BBS 2026 Release · 1966–2025

Bushtit Population Trend in California

All statesForest birds

Bushtit in California has fallen sharply: down 52% on the route-weighted index since 1970.

-52%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 →
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 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 →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Bushtit has fallen sharply in California: down 52% on the route-weighted index since 1970.

Bushtit Population Forecast in California

If the recent trend holds, Bushtit in California is projected to stay roughly flat through 2030, near 3.0 (95% range 0.86–5.2). A 5-year backtest shows a typical error of ±21.2%, with 100% of held-out values landing inside the 95% band.

-3%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 →
3.0Projected 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 →
0.86–5.295% 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 →
±21.2%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 stay roughly flat through 2030, near 3.0 (95% range 0.86–5.2). A 5-year backtest shows a typical error of ±21.2%, with 100% 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 →
20263.21.05.4
20273.20.985.3
20283.10.945.3
20293.10.905.3
20303.00.865.2

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
Santa Ynez3520191969
Auburn3519801969
Jackson3019921972
Moraga2820251972
Mt Pinos 22620212010
Jofegan 22520252024
Colma2419721968
Cuyamaca Pk2420251970
Orland2120221988
Elsinore Mtn2120251970
Orange Cove1720161972
Greenhorn Mt1720061973
Stonyford1620182016
San Ysidro1520191973
Sanger1520242011
Coulterville1520191997
Yokohl Val1419971972
Fairfax1420241972
Redding1419801972
Oneals1420241972
Coalinga1320141973
Lake Success1319961972

Bushtit Population Trend in Other States

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