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Species · California · BBS 2026 Release · 1966–2025

Chestnut-backed Chickadee Population Trend in California

All statesForest birds

Chestnut-backed Chickadee in California has declined: down 39% on the route-weighted index since 1970.

-39%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 →
75Routes 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 Chestnut-backed Chickadee 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 Chestnut-backed Chickadee in California. See the full index history below.

Chestnut-backed Chickadee Population Forecast in California

If the recent trend holds, Chestnut-backed Chickadee in California is projected to fall about 25% by 2030 — from 3.2 in 2025 to a central estimate of 2.4 (95% range 0.57–4.2). A 5-year backtest shows a typical error of ±8.6%, with 100% of held-out values landing inside the 95% band.

-25%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 →
2.4Projected 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 →
0.57–4.295% 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 →
±8.6%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, Chestnut-backed Chickadee in California is projected to fall about 25% by 2030 — from 3.2 in 2025 to a central estimate of 2.4 (95% range 0.57–4.2). A 5-year backtest shows a typical error of ±8.6%, 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 →
20262.40.604.3
20272.40.594.3
20282.40.594.3
20292.40.584.2
20302.40.574.2

Chestnut-backed Chickadee Survey Routes in California

Routes recording Chestnut-backed Chickadee 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 →
Colma10719721968
Crescent Cty5820251972
Moraga4320251972
Point Reyes3420251970
Fairfax3020241972
Holmes2720251968
Korbel2720251972
Redwood N.P. 22620132012
Fish Rock2520141968
Waterman Gap2120251972
Creston1819831983
Coyote1820251972
Glen Ellen1620041972
Alderpoint1520121974
Friday Ridge1320251994
Honeydew1020171968
Pilot Creek919961995
Redwood N.P.820101995
Pescadero720251992
Rio Dell720121972
Laytonville620251972
Ukiah620111988
Carmel Val620251974
Burnt Ranch520162004
Mark West520251975

Chestnut-backed Chickadee Population Trend in Other States

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