BirdAnalyst
Species · BCR 30 · BBS 2026 Release · 1966–2025

Worm-eating Warbler In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastForest birds

Worm-eating Warbler in New England / Mid-Atlantic Coast has surged: up 549% on the route-weighted index since 1968.

+549%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 →
97Routes 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 →
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 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 →

Worm-eating Warbler has surged in New England / Mid-Atlantic Coast: up 549% on the route-weighted index since 1968.

Worm-eating Warbler In New England / Mid-Atlantic Coast Population Forecast

If the recent trend holds, Worm-eating Warbler in New England / Mid-Atlantic Coast is projected to fall about 28% by 2030 — from 1.0 in 2025 to a central estimate of 0.72 (95% range 0.45–0.99). A 5-year backtest shows a typical error of ±37.1%, with 20% of held-out values landing inside the 95% band.

-28%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 →
0.72Projected 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 →
0.45–0.9995% 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 →
±37.1%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, Worm-eating Warbler in New England / Mid-Atlantic Coast is projected to fall about 28% by 2030 — from 1.0 in 2025 to a central estimate of 0.72 (95% range 0.45–0.99). A 5-year backtest shows a typical error of ±37.1%, with 20% 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 →
20260.680.410.95
20270.690.420.96
20280.700.430.97
20290.710.440.98
20300.720.450.99

Routes In New England / Mid-Atlantic Coast

Routes recording Worm-eating Warbler in New England / Mid-Atlantic Coast.
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 →
CokesburyMARYLAND122025
HongaMARYLAND92025
Pepperbox 2DELAWARE72025
MadisonMARYLAND72025
UncasvilleCONNECTICUT62025
MillsboroDELAWARE62025
WillimanticCONNECTICUT52018
Island CreekMARYLAND52025
WalnutMARYLAND42024
BerlinMARYLAND42025
TruhartVIRGINIA42024
WestbrookCONNECTICUT32024
PepperboxDELAWARE32016
IndiantownMARYLAND32014
Warren 2MASSACHUSETTS32010
GreenwichNEW-JERSEY32013
WinslowNEW-JERSEY32007
MysticCONNECTICUT22014
DanburyCONNECTICUT22023
Long HillCONNECTICUT22019
HarringtonDELAWARE22016
Holleyville 2DELAWARE22015
PomonkeyMARYLAND22025
Snow HillMARYLAND21976
Furnace TownMARYLAND22025

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