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Species · BCR 14 · BBS 2025 Release · 1966–2024

Willow Flycatcher In Atlantic Northern Forest

All regionsAtlantic Northern ForestAerial insectivores

Willow Flycatcher in Atlantic Northern Forest has surged: up 432% on the route-weighted index since 1968.

+432%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 →
89Routes In RegionSurvey 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 SignalsNotable 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 Atlantic Northern Forest: up 431% on the route-weighted index since 1968.

Willow Flycatcher In Atlantic Northern Forest Population Forecast

If the recent trend holds, Willow Flycatcher in Atlantic Northern Forest is projected to stay roughly flat through 2029, near 0.24 (95% range 0.07–0.40). A 5-year backtest shows a typical error of ±23.3%, with 100% of held-out values landing inside the 95% band.

-2%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 →
0.24Projected 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 →
0.07–0.4095% 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 →
±23.3%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 Atlantic Northern Forest is projected to stay roughly flat through 2029, near 0.24 (95% range 0.07–0.40). A 5-year backtest shows a typical error of ±23.3%, with 100% of held-out values landing inside the 95% band.19662029
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 →
20250.230.060.40
20260.230.070.40
20270.230.070.40
20280.230.070.40
20290.240.070.40

Routes In Atlantic Northern Forest

Routes recording Willow Flycatcher in Atlantic Northern Forest.
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 FlsVERMONT101997
GabrielsNEW-YORK41998
DannemoraNEW-YORK41995
W RutlandVERMONT42024
New HartfordCONNECTICUT31987
ChesterfieldMASSACHUSETTS32021
East CalaisVERMONT31983
Wilson MillsMAINE21990
Otisfield GrMAINE22000
CharlestonMAINE22014
WytopitlockMAINE21996
BenedictaMAINE21993
WilmotNEW-HAMPSHIRE22019
Jefferson HlNEW-HAMPSHIRE22024
StratfordNEW-HAMPSHIRE22002
PetersburgNEW-YORK22011
S WallingfrdVERMONT22021
FletcherVERMONT22024
New HartfordCONNECTICUT11994
WestbrookMAINE12014
BiddefordMAINE12008
TurnerMAINE12010
GreenwoodMAINE12021
ReedsMAINE12022
HartfordMAINE12019

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