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

Mallard Population Trend in Wisconsin

All statesWaterfowl

Mallard in Wisconsin has fallen sharply: down 55% on the route-weighted index since 1968.

-55%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 →
98Routes 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 Mallard Trends in WisconsinNotable 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 →

Mallard has fallen sharply in Wisconsin: down 54% on the route-weighted index since 1968.

Mallard Population Forecast in Wisconsin

If the recent trend holds, Mallard in Wisconsin is projected to rise about 43% by 2029 — from 2.7 in 2024 to a central estimate of 3.9 (95% range 0.29–7.4). A 5-year backtest shows a typical error of ±70.1%, with 100% of held-out values landing inside the 95% band.

+43%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 →
3.9Projected 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 →
0.29–7.495% 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 →
±70.1%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 Wisconsin is projected to rise about 43% by 2029 — from 2.7 in 2024 to a central estimate of 3.9 (95% range 0.29–7.4). A 5-year backtest shows a typical error of ±70.1%, 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 →
20253.90.387.5
20263.90.357.5
20273.90.337.5
20283.90.317.4
20293.90.297.4

Mallard Survey Routes in Wisconsin

Routes recording Mallard in Wisconsin.
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 →
Omro3420011966
Holland3320242001
Kiel1520221999
Pt Washingtn1320241966
Raymond1320241967
Omro 21320242002
Hatfield1219941970
Gilman1120241973
Unity1120241968
Stevens Pt1120211967
Hudson1020241966
Manitowoc1020241966
Holway919891973
Hollister820241970
Stratford820241967
Rolling Grnd820111986
Rolling Pr820241966
Wiota820241975
Buena Vista820241998
Rib Lake720231967
Princeton720191967
Irma620241971
Mount Horeb619901969
Weyerhauser520241967
Manawa520241967

Mallard Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawyoming

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