BirdAnalyst
Species · Vermont · BBS 2025 Release · 1966–2024

Blackburnian Warbler Population Trend in Vermont

All statesForest birds

Blackburnian Warbler in Vermont has surged: up 400% on the route-weighted index since 1968.

+400%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 →
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 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 400% 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 stay roughly flat through 2029, near 3.0 (95% range 2.0–3.9). A 5-year backtest shows a typical error of ±16.7%, with 100% of held-out values landing inside the 95% band.

-1%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 →
3.0Projected 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 →
2.0–3.995% 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 →
±16.7%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 stay roughly flat through 2029, near 3.0 (95% range 2.0–3.9). A 5-year backtest shows a typical error of ±16.7%, with 100% 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 →
20252.81.93.7
20262.81.93.7
20272.92.03.8
20282.92.03.8
20293.02.03.9

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 →
Stratton1020241967
East Calais920241966
East Haven820241966
Stowe720241988
Middlesex620241968
Marlboro520241967
Northfld Fls520211980
North Pownal420061984
Landgrove420241969
Post Mills220171967
St Johnsbury220221972
Hardwick220241966
Greensboro220241967
Waterville219801979
Newbury 2220232008
S Reading120141968
Gaysville120211967
Shaftsbury120241976
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 2026-05-22.