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

Warbling Vireo Population Trend in Vermont

All statesForest birds

Warbling Vireo in Vermont has surged: up 125% on the route-weighted index since 1968.

+125%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 →
26Routes 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 Warbling Vireo 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 →

Warbling Vireo has surged in Vermont: up 125% on the route-weighted index since 1968.

Warbling Vireo Population Forecast in Vermont

If the recent trend holds, Warbling Vireo in Vermont is projected to rise about 50% by 2029 — from 2.2 in 2024 to a central estimate of 3.3 (95% range 1.4–5.1). A 5-year backtest shows a typical error of ±42%, with 100% of held-out values landing inside the 95% band.

+50%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 →
3.3Projected 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 →
1.4–5.195% 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 →
±42%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, Warbling Vireo in Vermont is projected to rise about 50% by 2029 — from 2.2 in 2024 to a central estimate of 3.3 (95% range 1.4–5.1). A 5-year backtest shows a typical error of ±42%, 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 →
20253.21.35.0
20263.21.45.0
20273.21.45.0
20283.21.45.1
20293.31.45.1

Warbling Vireo Survey Routes in Vermont

Routes recording Warbling Vireo 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 →
Hinesburg1319941966
Fletcher1220241969
W Rutland620241966
Shaftsbury520241966
S Wallingfrd520221966
Waterville519801967
Gaysville420211977
Grand Isle420241967
Bristol420181995
East Haven320241968
Newbury320041988
S Reading220241966
Post Mills220241966
St Johnsbury220181970
Middlesex220031968
Marlboro120181966
North Pownal120231978
Stratton120231968
Landgrove120241974
Northfld Fls120211980
East Calais120241974
Hardwick120241972
Greensboro120231973
Colchester120241986
Newbury 2120232005

Warbling Vireo Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawareidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvirginiawashingtonwest-virginiawisconsinwyoming

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