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

Nashville Warbler Population Trend in Vermont

All statesForest birds

Nashville Warbler in Vermont has edged down: down 13% on the route-weighted index since 1968.

-13%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 →
24Routes 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 Nashville 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 →

No notable trend signals for Nashville Warbler in Vermont. See the full index history below.

Nashville Warbler Population Forecast in Vermont

If the recent trend holds, Nashville Warbler in Vermont is projected to stay roughly flat through 2029, near 0.55 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±15.6%, 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 →
0.55Projected 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 →
0.00–1.595% 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 →
±15.6%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, Nashville Warbler in Vermont is projected to stay roughly flat through 2029, near 0.55 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±15.6%, 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 →
20250.590.001.5
20260.580.001.5
20270.570.001.5
20280.560.001.5
20290.550.001.5

Nashville Warbler Survey Routes in Vermont

Routes recording Nashville 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 →
Newbury 2520232009
East Calais420241966
S Reading319981968
Newbury319941987
East Haven220241972
Waterville219801980
Marlboro119911969
North Pownal119921979
Stratton120241969
Landgrove120231968
Gaysville120101981
Post Mills120041967
Shaftsbury120231978
S Wallingfrd119971982
W Rutland120141989
St Johnsbury120231970
Northfld Fls120141980
Middlesex120241968
Hardwick120241972
Greensboro120241967
Fletcher120091983
Hinesburg119861977
Colchester120051993
Stowe120101991

Nashville Warbler Population Trend in Other States

californiaconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-dakotaoregonpennsylvaniarhode-islandvirginiawashingtonwest-virginiawisconsin

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