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

Mallard Population Trend in Vermont

All statesWaterfowl

Mallard in Vermont has surged: up 35× on the route-weighted index since 1970.

35×Since 1970TrendPercent 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 →
24Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Mallard 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 →

Mallard has surged in Vermont: up 35× on the route-weighted index since 1970.

Mallard Population Forecast in Vermont

If the recent trend holds, Mallard in Vermont is projected to stay roughly flat through 2029, near 2.2 (95% range 0.49–3.8). A 5-year backtest shows a typical error of ±40.5%, with 80% of held-out values landing inside the 95% band.

-7%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 →
2.2Projected 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 →
0.49–3.895% 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 →
±40.5%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, Mallard in Vermont is projected to stay roughly flat through 2029, near 2.2 (95% range 0.49–3.8). A 5-year backtest shows a typical error of ±40.5%, with 80% of held-out values landing inside the 95% band.19672029
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 →
20252.00.343.7
20262.10.383.7
20272.10.413.8
20282.10.453.8
20292.20.493.8

Mallard Survey Routes in Vermont

Routes recording Mallard 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 →
Fletcher7520231990
Landgrove1720241997
Grand Isle1520241967
Middlesex920231990
Hinesburg419911977
Marlboro220241972
North Pownal220241974
S Reading220191993
Shaftsbury220131990
S Wallingfrd220181973
W Rutland220241974
East Calais220191974
Greensboro220241995
Stowe220101998
Bristol220141998
Stratton120192015
Gaysville120181986
Post Mills120241967
St Johnsbury120231998
East Haven120221987
Northfld Fls120111986
Hardwick120131978
Colchester120241989
Newbury 2120232012

Mallard Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvirginiawashingtonwest-virginiawisconsinwyoming

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