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

Black-throated Green Warbler In New England / Mid-Atlantic Coast

All regionsNew England / Mid-Atlantic CoastForest birds

Black-throated Green Warbler in New England / Mid-Atlantic Coast has declined: down 37% on the route-weighted index since 1968.

-37%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 →
50Routes 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 →

No notable trend signals for Black-throated Green Warbler in New England / Mid-Atlantic Coast. See the full index history below.

Black-throated Green Warbler In New England / Mid-Atlantic Coast Population Forecast

If the recent trend holds, Black-throated Green Warbler in New England / Mid-Atlantic Coast is projected to rise about 223% by 2030 — from 0.08 in 2025 to a central estimate of 0.26 (95% range 0.10–0.43). A 5-year backtest shows a typical error of ±183.5%, with 0% of held-out values landing inside the 95% band.

+223%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 →
0.26Projected 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 →
0.10–0.4395% 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 →
±183.5%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, Black-throated Green Warbler in New England / Mid-Atlantic Coast is projected to rise about 223% by 2030 — from 0.08 in 2025 to a central estimate of 0.26 (95% range 0.10–0.43). A 5-year backtest shows a typical error of ±183.5%, with 0% 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 →
20260.260.090.43
20270.260.090.43
20280.260.100.43
20290.260.100.43
20300.260.100.43

Routes In New England / Mid-Atlantic Coast

Routes recording Black-throated Green 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 →
WarrenCONNECTICUT192011
Ware RiverMASSACHUSETTS52022
PulaskiRHODE-ISLAND41992
MysticCONNECTICUT22004
ShermanCONNECTICUT22010
Warren 2CONNECTICUT22025
PrincetonMASSACHUSETTS21976
N. AndoverMASSACHUSETTS22004
BrentwoodNEW-HAMPSHIRE21996
East KingstonNEW-HAMPSHIRE22017
E HartlandCONNECTICUT11966
BuckinghamCONNECTICUT11984
UncasvilleCONNECTICUT12023
WoodstockCONNECTICUT12007
WestbrookCONNECTICUT11998
WillimanticCONNECTICUT12017
No WoodburyCONNECTICUT12023
GreenwichCONNECTICUT11972
Long HillCONNECTICUT12019
Mid HaddamCONNECTICUT12005
SouthingtonCONNECTICUT12010
Woodstock 2CONNECTICUT12025
GranbyCONNECTICUT12024
Cape NeddickMAINE12023
Kittery PtMAINE12023

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