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

Black-throated Blue Warbler In Atlantic Northern Forest

All regionsAtlantic Northern ForestForest birds

Black-throated Blue Warbler in Atlantic Northern Forest has surged: up 134% on the route-weighted index since 1968.

+134%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 →
155Routes 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 →
58YearsYears 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 →

Black-throated Blue Warbler has surged in Atlantic Northern Forest: up 134% on the route-weighted index since 1968.

Black-throated Blue Warbler In Atlantic Northern Forest Population Forecast

If the recent trend holds, Black-throated Blue Warbler in Atlantic Northern Forest is projected to rise about 64% by 2029 — from 2.3 in 2024 to a central estimate of 3.8 (95% range 2.6–4.9). A 5-year backtest shows a typical error of ±49.4%, with 60% of held-out values landing inside the 95% band.

+64%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 →
3.8Projected 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 →
2.6–4.995% 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 →
±49.4%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 Atlantic Northern Forest is projected to rise about 64% by 2029 — from 2.3 in 2024 to a central estimate of 3.8 (95% range 2.6–4.9). A 5-year backtest shows a typical error of ±49.4%, with 60% 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 →
20253.62.54.8
20263.72.54.8
20273.72.64.8
20283.72.64.9
20293.82.64.9

Routes In Atlantic Northern Forest

Routes recording Black-throated Blue Warbler 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 →
PittsfieldMASSACHUSETTS222016
CharlestonMAINE202019
Horse MtnMAINE162011
InletNEW-YORK142017
Blue Ridge SNEW-YORK132010
Horseshoe L.NEW-YORK132017
BrooksMAINE122019
WaiteMAINE121977
Old ForgeNEW-YORK112006
HermonMAINE102019
Forest StaMAINE102000
ReedsMAINE92024
HudsonMAINE92016
SabattisNEW-YORK91983
NorthfieldMAINE81981
Carrying PlMAINE82024
Clayton LakeMAINE82008
LudlowMAINE81995
Dexter LakeNEW-YORK81975
Old Forge 2NEW-YORK82019
Underwood 2NEW-YORK82005
Seboomook LkMAINE72014
Pillsbury PdMAINE71968
WilmotNEW-HAMPSHIRE72024
Mt ChocoruaNEW-HAMPSHIRE72024

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