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

Canada Warbler Population Trend in Vermont

All statesForest birds

Canada Warbler in Vermont has collapsed: down 80% on the route-weighted index since 1968.

-80%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 →
22Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Canada 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 declinecomputed 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 →

Canada Warbler has collapsed in Vermont: down 80% on the route-weighted index since 1968.

Canada Warbler Population Forecast in Vermont

If the recent trend holds, Canada Warbler in Vermont is projected to fall about 100% by 2029 — from 0.17 in 2024 to a central estimate of 0.00 (95% range 0.00–0.81). A 5-year backtest shows a typical error of ±117.6%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.8195% 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 →
±117.6%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, Canada Warbler in Vermont is projected to fall about 100% by 2029 — from 0.17 in 2024 to a central estimate of 0.00 (95% range 0.00–0.81). A 5-year backtest shows a typical error of ±117.6%, 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 →
20250.070.000.88
20260.050.000.86
20270.030.000.84
20280.010.000.83
20290.000.000.81

Canada Warbler Survey Routes in Vermont

Routes recording Canada 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 →
Waterville619801967
Landgrove219981968
S Wallingfrd220071994
St Johnsbury220161970
Northfld Fls220111980
Newbury220031986
Marlboro119891967
North Pownal119931969
Stratton120231976
S Reading120041968
Gaysville120101967
Post Mills120071967
Shaftsbury119971973
W Rutland120241979
East Haven120241967
Middlesex120231968
East Calais120241966
Hardwick120061966
Greensboro120131967
Fletcher119751975
Newbury 2120182010
Stowe120231988

Canada Warbler Population Trend in Other States

connecticutgeorgiaindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiopennsylvaniarhode-islandtennesseevirginiawest-virginiawisconsin

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