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

Willow Flycatcher Population Trend in Washington

All statesAerial insectivores

Willow Flycatcher in Washington has fallen sharply: down 65% on the route-weighted index since 1970.

-65%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 →
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 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 65% 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 43% by 2029 — from 5.5 in 2024 to a central estimate of 3.1 (95% range 0.00–7.0). A 5-year backtest shows a typical error of ±39%, with 100% of held-out values landing inside the 95% band.

-43%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 →
3.1Projected 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 →
0.00–7.095% 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 →
±39%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 43% by 2029 — from 5.5 in 2024 to a central estimate of 3.1 (95% range 0.00–7.0). A 5-year backtest shows a typical error of ±39%, 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 →
20253.60.007.5
20263.50.007.4
20273.40.007.3
20283.30.007.1
20293.10.007.0

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 34620242005
Issaquah3619871969
Mendota 23220001989
Montesand3120241986
Kendall2520241981
Mendota2519881977
South Elma2420241975
Everett2320241975
Raymond1920211993
Mcchord1920151996
Index1819711968
Carnation1620241988
Port Angeles1520241970
Rainier1520191993
Newhalem1220241968
Cougar1220231982
Hurricane Rg1220241995
Cedar Falls1220141992
Waitsburg1220041994
Mukilteo1120241993
Deer Park1020151994
Raymond 21020242022
Mt St Helens920241992
Turnbull Nwr820231993
Warm Beach720171968

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 2026-05-22.