BirdAnalyst
Species · Washington · BBS 2025 Release · 1966–2024

Western Tanager Population Trend in Washington

All statesGeneralists

Western Tanager in Washington has surged: up 83% on the route-weighted index since 1970.

+83%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 →
85Routes 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 →
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 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 83% 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 2029, near 15 (95% range 11–19). A 5-year backtest shows a typical error of ±9.6%, with 100% of held-out values landing inside the 95% band.

-7%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 →
15Projected 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 →
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 →
±9.6%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 Washington is projected to stay roughly flat through 2029, near 15 (95% range 11–19). A 5-year backtest shows a typical error of ±9.6%, 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 →
2025141018
2026141019
2027151019
2028151119
2029151119

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 Pass10120241992
Cusick5220241982
E. Mt. Adams4820241995
Carlton4620221992
L Pend O Nwr4520241995
Rimrock3920241968
Omak Creek3920241996
Ronald3320241973
Snowden3220241971
Cloverland3120241993
Mendota 33120242005
Kendall2920241981
Cedar Falls2920141993
Mazama2920221993
Camas2820091982
Leavenworth2720241981
L. Wenatchee2620241993
Mt. Adams2520241993
Glacier2420241975
Twin Lakes2420241983
Sullivan Lk2419991999
Winthrop2320221983
Spring Lake2220241982
Index 22220232014
Cougar2120231968

Western Tanager Population Trend in Other States

alaskaarizonacaliforniacoloradoidahomontananebraskanevadanew-mexicooregonsouth-dakotatexasutahwyoming

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