BirdAnalyst
Species · Vermont · BBS 2026 Release · 1966–2025

Blackburnian Warbler Population Trend in Vermont

All statesForest birds

Blackburnian Warbler in Vermont has surged: up 457% on the route-weighted index since 1968.

+457%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 Blackburnian 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 →

Blackburnian Warbler has surged in Vermont: up 456% on the route-weighted index since 1968.

Blackburnian Warbler Population Forecast in Vermont

If the recent trend holds, Blackburnian Warbler in Vermont is projected to fall about 17% by 2030 — from 3.7 in 2025 to a central estimate of 3.1 (95% range 2.1–4.0). A 5-year backtest shows a typical error of ±13.7%, with 80% of held-out values landing inside the 95% band.

-17%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 →
3.1Projected 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 →
2.1–4.095% 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 →
±13.7%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, Blackburnian Warbler in Vermont is projected to fall about 17% by 2030 — from 3.7 in 2025 to a central estimate of 3.1 (95% range 2.1–4.0). A 5-year backtest shows a typical error of ±13.7%, with 80% 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 →
20262.92.03.8
20272.92.03.9
20283.02.13.9
20293.02.14.0
20303.12.14.0

Blackburnian Warbler Survey Routes in Vermont

Routes recording Blackburnian 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 →
Marlboro1120251967
Landgrove1020251969
Gaysville820251967
Northfld Fls820251980
Stratton720251967
Stowe720241988
Middlesex620251968
Greensboro520251967
North Pownal420061984
East Calais420251966
Shaftsbury320251976
East Haven320251966
Post Mills220171967
St Johnsbury220251972
Hardwick220241966
Waterville219801979
Newbury 2220232008
S Reading120141968
S Wallingfrd120212021
W Rutland120221996
Newbury120041986
Fletcher120221983
Hinesburg119891989
Colchester119901986
Grand Isle119931983

Blackburnian Warbler Population Trend in Other States

connecticutgeorgiaindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiopennsylvaniarhode-islandtennesseevirginiawest-virginiawisconsin

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