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

Alder Flycatcher Population Trend in Vermont

All statesAerial insectivores

Alder Flycatcher in Vermont has surged: up 233% on the route-weighted index since 1968.

+233%Since 1968TrendPercent 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 →
25Routes 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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Alder 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 →

Alder Flycatcher has surged in Vermont: up 233% on the route-weighted index since 1968.

Alder Flycatcher Population Forecast in Vermont

If the recent trend holds, Alder Flycatcher in Vermont is projected to rise about 21% by 2030 — from 4.9 in 2025 to a central estimate of 5.9 (95% range 4.1–7.8). A 5-year backtest shows a typical error of ±14.2%, with 100% of held-out values landing inside the 95% band.

+21%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 →
5.9Projected 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 →
4.1–7.895% 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 →
±14.2%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, Alder Flycatcher in Vermont is projected to rise about 21% by 2030 — from 4.9 in 2025 to a central estimate of 5.9 (95% range 4.1–7.8). A 5-year backtest shows a typical error of ±14.2%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20265.73.87.5
20275.73.97.6
20285.84.07.6
20295.94.07.7
20305.94.17.8

Alder Flycatcher Survey Routes in Vermont

Routes recording Alder 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 →
Hardwick1320241968
Stratton1220251973
Middlesex1220251968
Stowe1120241988
Greensboro1020251967
Newbury 21020232005
East Haven920251966
St Johnsbury820251970
Landgrove720251966
East Calais620251966
W Rutland520251968
Shaftsbury420251973
Fletcher420252008
Bristol420171998
S Reading320241969
Post Mills320251975
S Wallingfrd320221967
Hinesburg319931982
Marlboro220251968
Gaysville220251988
Northfld Fls220251980
Waterville219801979
North Pownal120251980
Newbury120041986
Colchester120251986

Alder Flycatcher Population Trend in Other States

alaskaconnecticutidahoillinoisindianaiowamainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-dakotavirginiawashingtonwest-virginiawisconsin

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