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Species · California · BBS 2025 Release · 1966–2024

Chestnut-backed Chickadee Population Trend in California

All statesForest birds

Chestnut-backed Chickadee in California has declined: down 46% on the route-weighted index since 1970.

-46%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 →
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 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 12% by 2029 — from 2.7 in 2024 to a central estimate of 2.4 (95% range 0.51–4.2). A 5-year backtest shows a typical error of ±18.6%, with 100% of held-out values landing inside the 95% band.

-12%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 →
2.4Projected 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 →
0.51–4.295% 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 →
±18.6%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 12% by 2029 — from 2.7 in 2024 to a central estimate of 2.4 (95% range 0.51–4.2). A 5-year backtest shows a typical error of ±18.6%, 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 →
20252.40.554.2
20262.40.544.2
20272.40.534.2
20282.40.524.2
20292.40.514.2

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 Cty3620241972
Waterman Gap3220241972
Fairfax3020241972
Holmes2820241968
Moraga2720241972
Redwood N.P. 22620132012
Fish Rock2520141968
Creston1819831983
Glen Ellen1620041972
Alderpoint1520121974
Point Reyes1520231970
Pescadero1420241992
Coyote1120241972
Korbel1120241972
Shasta Lake1120241976
Honeydew1020171968
Laytonville1020241972
Pilot Creek919961995
Carmel Val920241974
Redwood N.P.820101995
Mark West820241975
Friday Ridge820241994
Rio Dell720121972
Ukiah620111988

Chestnut-backed Chickadee Population Trend in Other States

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