BirdAnalyst
Species · BCR 10 · BBS 2025 Release · 1966–2024

Western Tanager In Northern Rockies

All regionsNorthern RockiesGeneralists

Western Tanager in Northern Rockies has surged: up 108% on the route-weighted index since 1970.

+108%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 →
183Routes 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 →

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 108% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Western Tanager in Northern Rockies is projected to stay roughly flat through 2029, near 10 (95% range 8.6–12). A 5-year backtest shows a typical error of ±7.6%, with 100% of held-out values landing inside the 95% band.

-0%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 →
10Projected 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 →
8.6–1295% 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 →
±7.6%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, Western Tanager in Northern Rockies is projected to stay roughly flat through 2029, near 10 (95% range 8.6–12). A 5-year backtest shows a typical error of ±7.6%, 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 →
2025108.212
2026108.312
2027108.412
2028108.512
2029108.612

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
DesolationOREGON632007
CascadeIDAHO541984
CusickWASHINGTON522024
CobaltIDAHO472024
SilviesOREGON472024
Black Mtn.OREGON462004
L Pend O NwrWASHINGTON452024
Deep CreekIDAHO441985
Threemile WaMONTANA422024
Mount VernonOREGON412024
Hash RockOREGON412024
Rochat DivdeIDAHO392023
BarnhouseOREGON392024
Omak CreekWASHINGTON392024
CabartonIDAHO382023
Greenoagh 3MONTANA382024
Hells CanyonOREGON352022
GrangevilleIDAHO332024
CoolinIDAHO332024
Summit PrOREGON332024
Buckskin MtnWYOMING322021
WoodmanMONTANA312024
CloverlandWASHINGTON312024
Cramer CreekMONTANA302019

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