BirdAnalyst
Species · BCR 30 · BBS 2025 Release · 1966–2024

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

All regionsNew England / Mid-Atlantic CoastForest birds

Black-throated Blue Warbler in New England / Mid-Atlantic Coast has increased: up 42% on the route-weighted index since 1968.

+42%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 →
28Routes 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 →

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

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

If the recent trend holds, Black-throated Blue Warbler in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 0.12 (95% range 0.04–0.20). A 5-year backtest shows a typical error of ±97.6%, with 80% of held-out values landing inside the 95% band.

n/aChange 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 →
0.12Projected 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 →
0.04–0.2095% 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 →
±97.6%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 Blue Warbler in New England / Mid-Atlantic Coast is projected to stay roughly flat through 2029, near 0.12 (95% range 0.04–0.20). A 5-year backtest shows a typical error of ±97.6%, with 80% 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 →
20250.120.040.20
20260.120.040.20
20270.120.040.20
20280.120.040.20
20290.120.040.20

Routes In New England / Mid-Atlantic Coast

Routes recording Black-throated Blue 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 →
WarrenCONNECTICUT42011
Ware RiverMASSACHUSETTS32022
E HartlandCONNECTICUT21985
WoodstockCONNECTICUT21994
ShermanCONNECTICUT22019
Mid HaddamCONNECTICUT21973
WestbrookCONNECTICUT11970
No WoodburyCONNECTICUT12015
GreenwichCONNECTICUT12009
Long HillCONNECTICUT11984
SouthingtonCONNECTICUT12016
Woodstock 2CONNECTICUT12023
Warren 2CONNECTICUT12024
GranbyCONNECTICUT12023
MaynardMASSACHUSETTS11970
PrincetonMASSACHUSETTS11974
E PepperellMASSACHUSETTS11970
BelchertownMASSACHUSETTS12024
S BarreMASSACHUSETTS12022
HoldenMASSACHUSETTS12008
Warren 2MASSACHUSETTS12017
BrentwoodNEW-HAMPSHIRE11984
DoverNEW-HAMPSHIRE11973
EpsomNEW-HAMPSHIRE12017
StraffordNEW-HAMPSHIRE12022

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