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

Northern Parula Population Trend in Vermont

All statesForest birds

Northern Parula in Vermont has surged: up 17× on the route-weighted index since 1968.

17×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 →
20Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern Parula 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 →

Northern Parula has surged in Vermont: up 17× on the route-weighted index since 1968.

Northern Parula Population Forecast in Vermont

If the recent trend holds, Northern Parula in Vermont is projected to fall about 21% by 2030 — from 2.8 in 2025 to a central estimate of 2.2 (95% range 1.5–2.8). A 5-year backtest shows a typical error of ±15.7%, with 80% of held-out values landing inside the 95% band.

-21%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 →
2.2Projected 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 →
1.5–2.895% 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 →
±15.7%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, Northern Parula in Vermont is projected to fall about 21% by 2030 — from 2.8 in 2025 to a central estimate of 2.2 (95% range 1.5–2.8). A 5-year backtest shows a typical error of ±15.7%, 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 →
20262.01.42.7
20272.11.42.7
20282.11.52.8
20292.11.52.8
20302.21.52.8

Northern Parula Survey Routes in Vermont

Routes recording Northern Parula 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 →
Middlesex1220251968
East Calais1020251966
Greensboro920251967
East Haven720251966
Northfld Fls420251991
Hardwick420241968
Newbury 2420232008
Landgrove320252017
Gaysville220251983
St Johnsbury220251970
Stowe220241996
Marlboro120222018
North Pownal119791979
Stratton120251971
S Reading119921990
Post Mills120241998
W Rutland120022002
Newbury120041987
Fletcher120152011
Hinesburg119781978

Northern Parula Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvirginiawest-virginiawisconsin

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