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

Wilson's Warbler Population Trend in Washington

All statesForest birds

Wilson's Warbler in Washington has declined: down 32% on the route-weighted index since 1970.

-32%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 →
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 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 37% by 2029 — from 6.0 in 2024 to a central estimate of 3.7 (95% range 1.1–6.4). A 5-year backtest shows a typical error of ±30.5%, with 100% of held-out values landing inside the 95% band.

-37%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 →
3.7Projected 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 →
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 →
±30.5%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 37% by 2029 — from 6.0 in 2024 to a central estimate of 3.7 (95% range 1.1–6.4). A 5-year backtest shows a typical error of ±30.5%, 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 →
20253.91.36.6
20263.91.26.6
20273.81.26.5
20283.81.16.5
20293.71.16.4

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 →
Ozette5920241971
Raymond 25620242022
Pe Ell3720231993
Raymond3120211993
Kamilche2920241968
Mendota2719881977
Montesand2620241986
Kendall2520241981
Taholah2420221969
Vashon Is.2320241995
Mendota 32020242005
Hurricane Rg1520241992
Port Angeles1120241970
Bunker Hill1020241968
Snowden1020241984
Cedar Falls1020141993
Issaquah919871969
South Elma920241975
Mendota 2920001989
Cusick820241982
Leavenworth820151985
E. Mt. Adams720241995
Ilwaco620241975
Neilton519751975
Concrete520192013

Wilson's Warbler Population Trend in Other States

alaskacaliforniacoloradoidahomainemichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorkoregonutahvermontwisconsinwyoming

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