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Species · Vermont · BBS 2026 Release · 1966–2025

Black-throated Blue Warbler Population Trend in Vermont

All statesForest birds

Black-throated Blue Warbler in Vermont has surged: up 255% on the route-weighted index since 1968.

+255%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 →
25Routes In StateSurvey 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 Black-throated Blue Warbler Trends in VermontNotable 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 Vermont: up 255% on the route-weighted index since 1968.

Black-throated Blue Warbler Population Forecast in Vermont

If the recent trend holds, Black-throated Blue Warbler in Vermont is projected to rise about 68% by 2030 — from 1.7 in 2025 to a central estimate of 2.9 (95% range 1.6–4.2). A 5-year backtest shows a typical error of ±54.5%, with 60% of held-out values landing inside the 95% band.

+68%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 →
2.9Projected 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 →
1.6–4.295% 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 →
±54.5%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 Blue Warbler in Vermont is projected to rise about 68% by 2030 — from 1.7 in 2025 to a central estimate of 2.9 (95% range 1.6–4.2). A 5-year backtest shows a typical error of ±54.5%, with 60% 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 →
20262.81.54.1
20272.81.54.1
20282.81.54.1
20292.91.64.2
20302.91.64.2

Black-throated Blue Warbler Survey Routes in Vermont

Routes recording Black-throated Blue Warbler in Vermont.
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 →
Stratton720251966
Northfld Fls520251980
Marlboro420251967
North Pownal320251971
Landgrove320251979
Gaysville320251966
Newbury320031986
Waterville319801968
Colchester319911990
Newbury 2320232008
Stowe320241989
Shaftsbury220231968
East Haven220251966
Greensboro220231969
S Reading120241966
Post Mills120181975
S Wallingfrd120221974
W Rutland120251987
St Johnsbury120251970
Middlesex120251968
East Calais120251967
Hardwick120241968
Fletcher120221999
Hinesburg119931969
Grand Isle119851985

Black-throated Blue Warbler Population Trend in Other States

connecticutgeorgiamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinapennsylvaniarhode-islandtennesseevirginiawest-virginiawisconsin

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