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

Willow Flycatcher Population Trend in Maine

All statesAerial insectivores

Willow Flycatcher in Maine has collapsed: down 80% on the route-weighted index since 1979.

-80%Since 1979TrendPercent 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 →
30Routes 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 →
42YearsYears 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 MaineNotable 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 collapsed in Maine: down 80% on the route-weighted index since 1979.

Willow Flycatcher Population Forecast in Maine

If the recent trend holds, Willow Flycatcher in Maine is projected to fall about 87% by 2027 — from 0.10 in 2022 to a central estimate of 0.01 (95% range 0.00–0.30). A 5-year backtest shows a typical error of ±95.8%, with 100% of held-out values landing inside the 95% band.

-87%Change by 2027TrendPercent 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 →
0.01Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3095% 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 →
±95.8%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 Maine is projected to fall about 87% by 2027 — from 0.10 in 2022 to a central estimate of 0.01 (95% range 0.00–0.30). A 5-year backtest shows a typical error of ±95.8%, with 100% of held-out values landing inside the 95% band.19702027
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 →
20230.030.000.31
20240.020.000.31
20250.020.000.30
20260.020.000.30
20270.010.000.30

Willow Flycatcher Survey Routes in Maine

Routes recording Willow Flycatcher in Maine.
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 →
Cape Neddick220121983
Wilson Mills219901990
Otisfield Gr220002000
Charleston220141991
Wytopitlock219961993
Benedicta219931993
Westbrook120141985
Biddeford120081989
Kittery Pt120131983
Turner120101986
Greenwood120212008
Reeds120222022
Hartford120191978
Bowdoin Ctr120042004
Manchester119831978
Warren119891988
Brooks120191993
Hermon119841982
Hancock120091970
Cooper119811980
Carrabassett120212021
Medway119921991
Hudson120002000
Ashland119861984
Cornville120222022

Willow Flycatcher Population Trend in Other States

alaskaarizonaarkansascaliforniacoloradoconnecticutdelawaregeorgiaidahoillinoisindianaiowakansaskentuckymarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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