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

Wilson's Warbler Population Trend in Washington

All statesForest birds

Wilson's Warbler in Washington has declined: down 34% on the route-weighted index since 1970.

-34%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 →
84Routes 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 Wilson's Warbler 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 →

No notable trend signals for Wilson's Warbler in Washington. See the full index history below.

Wilson's Warbler Population Forecast in Washington

If the recent trend holds, Wilson's Warbler in Washington is projected to fall about 15% by 2030 — from 4.4 in 2025 to a central estimate of 3.7 (95% range 1.1–6.4). A 5-year backtest shows a typical error of ±29.1%, with 100% of held-out values landing inside the 95% band.

-15%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 →
3.7Projected 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 →
1.1–6.495% 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 →
±29.1%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, Wilson's Warbler in Washington is projected to fall about 15% by 2030 — from 4.4 in 2025 to a central estimate of 3.7 (95% range 1.1–6.4). A 5-year backtest shows a typical error of ±29.1%, 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 →
20263.91.36.6
20273.91.26.5
20283.81.26.5
20293.81.16.4
20303.71.16.4

Wilson's Warbler Survey Routes in Washington

Routes recording Wilson's Warbler 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 →
Raymond 25620242022
Ozette4720251971
Raymond3120211993
Mendota2719881977
Montesand2620241986
Taholah2420221969
Kendall1820251981
Port Angeles1720251970
Kamilche1720251968
Vashon Is.1720251995
Bunker Hill1420251968
Pe Ell1420251993
Mendota 31220252005
Carnation1120251988
Hurricane Rg1020251992
Cedar Falls1020141993
Issaquah919871969
Ilwaco920251975
South Elma920241975
Mendota 2920001989
Leavenworth820151985
Neilton519751975
Deception520181992
Everett420251975
Lake Chelan420251989

Wilson's Warbler Population Trend in Other States

alaskacaliforniacoloradoidahomainemichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorkoregonutahvermontwisconsinwyoming

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