BirdAnalyst
Species · Washington · BBS 2026 Release · 1966–2025

Western Tanager Population Trend in Washington

All statesForest birds

Western Tanager in Washington has surged: up 90% on the route-weighted index since 1970.

+90%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 →
86Routes In StateSurvey 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 Western Tanager Trends in WashingtonNotable 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 Washington: up 90% on the route-weighted index since 1970.

Western Tanager Population Forecast in Washington

If the recent trend holds, Western Tanager in Washington is projected to stay roughly flat through 2030, near 15 (95% range 11–19). A 5-year backtest shows a typical error of ±11%, with 100% of held-out values landing inside the 95% band.

-6%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 →
15Projected 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 →
11–1995% 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 →
±11%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 Washington is projected to stay roughly flat through 2030, near 15 (95% range 11–19). A 5-year backtest shows a typical error of ±11%, 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 →
2026141019
2027151119
2028151119
2029151119
2030151119

Western Tanager Survey Routes in Washington

Routes recording Western Tanager in Washington.
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 →
Blewett Pass9620251992
E. Mt. Adams5220251995
Carlton4620221992
L. Wenatchee4520251993
L Pend O Nwr4520241995
Mendota 34220252005
Cloverland4020251993
Omak Creek3920241996
Spring Lake3620251982
Newhalem3120251968
Rimrock3120251968
Snowden3120251971
Kendall2920251981
Twin Lakes2920251983
Cedar Falls2920141993
Mazama2920221993
Camas2820091982
Ronald2820251973
Cusick2720251982
Leavenworth2720241981
Glacier2420241975
Sullivan Lk2419991999
Rainier2420251993
Winthrop2320221983
Index 22220232014

Western Tanager Population Trend in Other States

alaskaarizonacaliforniacoloradoidahomontananebraskanevadanew-mexicooregonsouth-dakotatexasutahwyoming

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