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

Chestnut-backed Chickadee In Coastal California

All regionsCoastal CaliforniaForest birds

Chestnut-backed Chickadee in Coastal 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 →
32Routes 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 Chestnut-backed Chickadee in Coastal California. See the full index history below.

Chestnut-backed Chickadee In Coastal California Population Forecast

If the recent trend holds, Chestnut-backed Chickadee in Coastal California is projected to stay roughly flat through 2030, near 3.8 (95% range 0.83–6.7). A 5-year backtest shows a typical error of ±56.5%, with 100% of held-out values landing inside the 95% band.

+4%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 →
3.8Projected 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 →
0.83–6.795% 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 →
±56.5%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 Coastal California is projected to stay roughly flat through 2030, near 3.8 (95% range 0.83–6.7). A 5-year backtest shows a typical error of ±56.5%, 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 →
20263.70.786.6
20273.70.806.7
20283.70.816.7
20293.80.826.7
20303.80.836.7

Routes In Coastal California

Routes recording Chestnut-backed Chickadee 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 →
ColmaCALIFORNIA1071972
MoragaCALIFORNIA432025
Point ReyesCALIFORNIA342025
FairfaxCALIFORNIA302024
Waterman GapCALIFORNIA212025
CrestonCALIFORNIA181983
CoyoteCALIFORNIA182025
Glen EllenCALIFORNIA162004
PescaderoCALIFORNIA72025
Carmel ValCALIFORNIA62025
Mark WestCALIFORNIA52025
ParkfieldCALIFORNIA42012
AlamarCALIFORNIA42001
RumseyCALIFORNIA31991
Santa YnezCALIFORNIA32014
Morro BayCALIFORNIA32019
SisquocCALIFORNIA32014
TehamaCALIFORNIA31981
CalpellaCALIFORNIA21986
Bartlett SpsCALIFORNIA22017
GreenfieldCALIFORNIA22017
Tres Pinos 2CALIFORNIA22010
Hollister 2CALIFORNIA22017
Red BluffCALIFORNIA12025
Tres PinosCALIFORNIA11994

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