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

Western Tanager In Sierra Nevada

All regionsSierra NevadaGeneralists

Western Tanager in Sierra Nevada has held roughly steady: up 5% on the route-weighted index since 1970.

+5%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 →
40Routes 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 Western Tanager in Sierra Nevada. See the full index history below.

Forecast

If the recent trend holds, Western Tanager in Sierra Nevada is projected to fall about 11% by 2029 — from 29 in 2024 to a central estimate of 26 (95% range 18–34). A 5-year backtest shows a typical error of ±13.9%, with 100% of held-out values landing inside the 95% band.

-11%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 →
26Projected 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 →
18–3495% 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 →
±13.9%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, Western Tanager in Sierra Nevada is projected to fall about 11% by 2029 — from 29 in 2024 to a central estimate of 26 (95% range 18–34). A 5-year backtest shows a typical error of ±13.9%, 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 →
2025251733
2026251734
2027261734
2028261834
2029261834

Routes In Sierra Nevada

Routes recording Western Tanager 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 →
Eagle LakeCALIFORNIA632024
JohnsvilleCALIFORNIA572024
LumberyardCALIFORNIA562024
PlacervilleCALIFORNIA542024
Pollock PinesCALIFORNIA402024
Pine MountainCALIFORNIA372017
LakeshoreCALIFORNIA352024
Greenhorn MtCALIFORNIA322008
Butte MeadowCALIFORNIA322014
CrestviewCALIFORNIA322024
WestvilleCALIFORNIA302024
GoumazCALIFORNIA302011
Silver CityCALIFORNIA292013
GeneseeCALIFORNIA292024
Chaos CraterCALIFORNIA282019
Forest HillCALIFORNIA272022
StrawberryCALIFORNIA252019
Tuolumne GroveCALIFORNIA222024
Little TruckeeCALIFORNIA222023
ChilcootCALIFORNIA212024
DownievilleCALIFORNIA202024
Kings CanyonCALIFORNIA182024
Tahoe NfCALIFORNIA181994
Forest Hill 2CALIFORNIA182005
WawonaCALIFORNIA172024

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