BirdAnalyst
Species · BCR 15 · BBS 2026 Release · 1966–2025

Bushtit In Sierra Nevada

All regionsSierra NevadaForest birds

Bushtit in Sierra Nevada has collapsed: down 81% on the route-weighted index since 1970.

-81%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 →
27Routes 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 →

long arc declinecomputed 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 →

Bushtit has collapsed in Sierra Nevada: down 81% on the route-weighted index since 1970.

Bushtit In Sierra Nevada Population Forecast

If the recent trend holds, Bushtit in Sierra Nevada is projected to rise about 40% by 2030 — from 1.2 in 2025 to a central estimate of 1.6 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±48%, with 100% of held-out values landing inside the 95% band.

+40%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 →
1.6Projected 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 →
0.00–5.195% 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 →
±48%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, Bushtit in Sierra Nevada is projected to rise about 40% by 2030 — from 1.2 in 2025 to a central estimate of 1.6 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±48%, 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 →
20261.80.005.3
20271.70.005.3
20281.70.005.2
20291.70.005.2
20301.60.005.1

Routes In Sierra Nevada

Routes recording Bushtit 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 →
Greenhorn MtCALIFORNIA172006
CoultervilleCALIFORNIA152019
Tuolumne GroveCALIFORNIA92015
SattleyCALIFORNIA81992
GeneseeCALIFORNIA81983
PaxtonCALIFORNIA82024
WoodfordsCALIFORNIA62025
WawonaCALIFORNIA52025
Cottage SpgsCALIFORNIA41975
JohnsvilleCALIFORNIA42015
LumberyardCALIFORNIA42025
Butte MeadowCALIFORNIA41990
Meadow ValleyCALIFORNIA42018
Bass LakeCALIFORNIA32019
Kings CanyonCALIFORNIA32016
DownievilleCALIFORNIA32019
Hat CreekCALIFORNIA31998
LakeshoreCALIFORNIA32024
Forest HillCALIFORNIA32025
Eagle LakeCALIFORNIA22025
WestvilleCALIFORNIA22023
Silver CityCALIFORNIA22013
Pine MountainCALIFORNIA22015
ChilcootCALIFORNIA22008
Higgins CornCALIFORNIA12025

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