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

Chestnut-sided Warbler Population Trend in Vermont

All statesForest birds

Chestnut-sided Warbler in Vermont has increased: up 42% on the route-weighted index since 1968.

+42%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 Chestnut-sided 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 Chestnut-sided Warbler in Vermont. See the full index history below.

Chestnut-sided Warbler Population Forecast in Vermont

If the recent trend holds, Chestnut-sided Warbler in Vermont is projected to fall about 27% by 2029 — from 14 in 2024 to a central estimate of 10.0 (95% range 6.1–14). A 5-year backtest shows a typical error of ±26%, with 40% of held-out values landing inside the 95% band.

-27%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 →
10.0Projected 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 →
6.1–1495% 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 →
±26%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, Chestnut-sided Warbler in Vermont is projected to fall about 27% by 2029 — from 14 in 2024 to a central estimate of 10.0 (95% range 6.1–14). A 5-year backtest shows a typical error of ±26%, with 40% 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 →
2025106.114
2026106.114
202710.06.114
202810.06.114
202910.06.114

Chestnut-sided Warbler Survey Routes in Vermont

Routes recording Chestnut-sided 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 →
Stowe3820241988
East Calais2220241966
S Wallingfrd1920221966
Hardwick1920241966
Waterville1919801968
Shaftsbury1820241966
Fletcher1820241971
Stratton1720241966
Marlboro1520241966
Gaysville1520211966
W Rutland1520241966
Middlesex1520241968
S Reading1420241966
Northfld Fls1220211980
Landgrove1020241966
Post Mills1020241966
St Johnsbury1020241970
East Haven1020241966
Newbury 2920232005
Greensboro820241967
North Pownal620241966
Newbury320041986
Hinesburg319941966
Bristol320181995
Colchester120241986

Chestnut-sided Warbler Population Trend in Other States

alabamaarkansascoloradoconnecticutgeorgiaillinoisindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandtennesseevirginiawest-virginiawisconsinwyoming

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