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

Willow Flycatcher Population Trend in Washington

All statesAerial insectivores

Willow Flycatcher in Washington has fallen sharply: down 63% on the route-weighted index since 1970.

-63%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 →
93Routes 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 Willow Flycatcher 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 declinecomputed 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 →

Willow Flycatcher has fallen sharply in Washington: down 62% on the route-weighted index since 1970.

Willow Flycatcher Population Forecast in Washington

If the recent trend holds, Willow Flycatcher in Washington is projected to fall about 48% by 2030 — from 6.1 in 2025 to a central estimate of 3.2 (95% range 0.00–7.1). A 5-year backtest shows a typical error of ±41.4%, with 100% of held-out values landing inside the 95% band.

-48%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 →
3.2Projected 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 →
0.00–7.195% 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 →
±41.4%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, Willow Flycatcher in Washington is projected to fall about 48% by 2030 — from 6.1 in 2025 to a central estimate of 3.2 (95% range 0.00–7.1). A 5-year backtest shows a typical error of ±41.4%, 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 →
20263.70.007.6
20273.60.007.5
20283.40.007.3
20293.30.007.2
20303.20.007.1

Willow Flycatcher Survey Routes in Washington

Routes recording Willow Flycatcher 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 →
Mendota 34820252005
Issaquah3619871969
Mendota 23220001989
Montesand3120241986
Rainier3020251993
Kendall2820251981
Mendota2519881977
Carnation2520251988
South Elma2420241975
Everett2120251975
Raymond1920211993
Mcchord1920151996
Newhalem1820251968
Index1819711968
Port Angeles1320251970
Cougar1220231982
Cedar Falls1220141992
Mukilteo1220251993
Lake Chelan1220251988
Waitsburg1220041994
Nighthawk1120251992
Pe Ell1120251993
Deer Park1020151994
Raymond 21020242022
Hurricane Rg920251995

Willow Flycatcher Population Trend in Other States

alaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawest-virginiawisconsinwyoming

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