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

American Black Duck Population Trend in Vermont

All statesWaterfowl

American Black Duck in Vermont has collapsed: down 87% on the route-weighted index since 1968.

-87%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 →
39YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable American Black Duck 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 →

American Black Duck has collapsed in Vermont: down 86% on the route-weighted index since 1968.

American Black Duck Population Forecast in Vermont

If the recent trend holds, American Black Duck in Vermont is projected to stay roughly flat through 2023, near 0.00 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±181%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2023TrendPercent 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 2023 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3395% 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 →
±181%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, American Black Duck in Vermont is projected to stay roughly flat through 2023, near 0.00 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±181%, with 100% of held-out values landing inside the 95% band.19662023
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 →
20190.000.000.33
20200.000.000.33
20210.000.000.33
20220.000.000.33
20230.000.000.33

American Black Duck Survey Routes in Vermont

Routes recording American Black Duck 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 →
Landgrove419991967
Post Mills419991966
Greensboro419881968
Marlboro319731967
East Haven319711969
North Pownal219751971
Gaysville220042004
Middlesex220121997
Hardwick219941967
Waterville219731973
Stratton120181976
S Reading119921990
Shaftsbury119661966
S Wallingfrd120031966
W Rutland120021968
East Calais120141974
Fletcher120081971
Hinesburg119881966
Grand Isle119991967
Bristol120092008

American Black Duck Population Trend in Other States

alabamaconnecticutdelawareindianamainemarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandvirginiawest-virginiawisconsin

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