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

Willow Flycatcher Population Trend in Vermont

All statesAerial insectivores

Willow Flycatcher in Vermont has surged: up 100% on the route-weighted index since 1977.

+100%Since 1977TrendPercent 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 →
24Routes 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 →
49YearsYears 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 VermontNotable 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 increasecomputed 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 surged in Vermont: up 100% on the route-weighted index since 1977.

Willow Flycatcher Population Forecast in Vermont

If the recent trend holds, Willow Flycatcher in Vermont is projected to rise about 14% by 2029 — from 0.44 in 2024 to a central estimate of 0.50 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±123.1%, with 100% of held-out values landing inside the 95% band.

+14%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 →
0.50Projected 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 →
0.00–1.395% 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 →
±123.1%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, Willow Flycatcher in Vermont is projected to rise about 14% by 2029 — from 0.44 in 2024 to a central estimate of 0.50 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±123.1%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20250.510.001.3
20260.510.001.3
20270.510.001.3
20280.510.001.3
20290.500.001.3

Willow Flycatcher Survey Routes in Vermont

Routes recording Willow Flycatcher in Vermont.
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 →
Northfld Fls1019971987
Bristol520001995
W Rutland420241986
East Calais319831977
S Wallingfrd220211983
Fletcher220242014
Hinesburg219941988
Marlboro120172017
North Pownal120211978
Stratton120121980
Landgrove120231988
S Reading120231977
Gaysville120101990
Post Mills120241977
Shaftsbury120231990
St Johnsbury120091986
East Haven119981992
Middlesex119861975
Hardwick120241993
Greensboro120091976
Colchester120141987
Grand Isle119981995
Newbury 2120212008
Stowe120222022

Willow Flycatcher Population Trend in Other States

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

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