BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Chestnut-backed Chickadee In Sierra Nevada

All regionsSierra NevadaForest birds

Chestnut-backed Chickadee in Sierra Nevada has surged: up 272% on the route-weighted index since 1976.

+272%Since 1976TrendPercent 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 →
10Routes 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 →
30YearsYears 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 →

long arc increasecomputed 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 →

Chestnut-backed Chickadee has surged in Sierra Nevada: up 272% on the route-weighted index since 1976.

Forecast

If the recent trend holds, Chestnut-backed Chickadee in Sierra Nevada is projected to rise about 28% by 2029 — from 0.63 in 2024 to a central estimate of 0.81 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±39.6%, with 80% of held-out values landing inside the 95% band.

+28%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 →
0.81Projected 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 →
0.00–1.795% 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 →
±39.6%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 Sierra Nevada is projected to rise about 28% by 2029 — from 0.63 in 2024 to a central estimate of 0.81 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±39.6%, with 80% of held-out values landing inside the 95% band.19732029
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 →
20250.750.001.6
20260.760.001.7
20270.780.001.7
20280.800.001.7
20290.810.001.7

Routes In Sierra Nevada

Routes recording Chestnut-backed Chickadee in Sierra Nevada.
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 →
WestvilleCALIFORNIA42024
Silver CityCALIFORNIA41976
Higgins CornCALIFORNIA42024
Forest HillCALIFORNIA32005
Tuolumne GroveCALIFORNIA22021
DownievilleCALIFORNIA22024
Butte MeadowCALIFORNIA11996
Pollock PinesCALIFORNIA12024
PlacervilleCALIFORNIA12024
CoultervilleCALIFORNIA12019

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