BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Chestnut-backed Chickadee In Coastal California

All regionsCoastal CaliforniaForest birds

Chestnut-backed Chickadee in Coastal 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 →
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 →
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 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.

Forecast

If the recent trend holds, Chestnut-backed Chickadee in Coastal California is projected to rise about 33% by 2029 — from 2.8 in 2024 to a central estimate of 3.8 (95% range 0.80–6.7). A 5-year backtest shows a typical error of ±87.4%, with 100% of held-out values landing inside the 95% band.

+33%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 →
3.8Projected 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 →
0.80–6.795% 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 →
±87.4%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 rise about 33% by 2029 — from 2.8 in 2024 to a central estimate of 3.8 (95% range 0.80–6.7). A 5-year backtest shows a typical error of ±87.4%, 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 →
20253.70.756.7
20263.70.766.7
20273.70.786.7
20283.70.796.7
20293.80.806.7

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
Waterman GapCALIFORNIA322024
FairfaxCALIFORNIA302024
MoragaCALIFORNIA272024
CrestonCALIFORNIA181983
Glen EllenCALIFORNIA162004
Point ReyesCALIFORNIA152023
PescaderoCALIFORNIA142024
CoyoteCALIFORNIA112024
Carmel ValCALIFORNIA92024
Mark WestCALIFORNIA82024
ParkfieldCALIFORNIA42012
AlamarCALIFORNIA42001
RumseyCALIFORNIA31991
Santa YnezCALIFORNIA32014
Morro BayCALIFORNIA32019
SisquocCALIFORNIA32014
TehamaCALIFORNIA31981
CalpellaCALIFORNIA21986
Bartlett SpsCALIFORNIA22017
GreenfieldCALIFORNIA22017
Tres Pinos 2CALIFORNIA22010
Hollister 2CALIFORNIA22017
Glen Ellen 3CALIFORNIA22024
Red BluffCALIFORNIA12002

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