BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Western Tanager In Northern Rockies

All regionsNorthern RockiesForest birds

Western Tanager in Northern Rockies has surged: up 117% on the route-weighted index since 1970.

+117%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 →
186Routes 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 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 →

Western Tanager has surged in Northern Rockies: up 117% on the route-weighted index since 1970.

Western Tanager In Northern Rockies Population Forecast

If the recent trend holds, Western Tanager in Northern Rockies is projected to stay roughly flat through 2030, near 11 (95% range 8.8–13). A 5-year backtest shows a typical error of ±8.9%, with 100% of held-out values landing inside the 95% band.

-5%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 →
11Projected 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 →
8.8–1395% 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 →
±8.9%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 Northern Rockies is projected to stay roughly flat through 2030, near 11 (95% range 8.8–13). A 5-year backtest shows a typical error of ±8.9%, 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 →
2026108.412
2027108.512
2028108.612
2029118.712
2030118.813

Routes In Northern Rockies

Routes recording Western Tanager in Northern Rockies.
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 →
DonnellyOREGON832006
WallowaOREGON572025
CascadeIDAHO541984
Buckskin MtnWYOMING512025
CobaltIDAHO472025
SilviesOREGON472024
Hash RockOREGON462025
BarnhouseOREGON462025
Black Mtn.OREGON462004
L Pend O NwrWASHINGTON452024
Deep CreekIDAHO441985
Greenoagh 3MONTANA412025
Mount VernonOREGON412024
CoolinIDAHO402025
CloverlandWASHINGTON402025
Hells CanyonOREGON392025
Omak CreekWASHINGTON392024
Threemile WaMONTANA372025
Spring LakeWASHINGTON362025
Silver CreekOREGON352025
Eagle CreekOREGON332025
Donelly 2OREGON332025
MivodenIDAHO322025
St RegisMONTANA322025
GrangevilleIDAHO312025

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