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

Green-winged Teal Population Trend in Wisconsin

All statesWaterfowl

Green-winged Teal in Wisconsin has held roughly steady: down 5% on the route-weighted index since 1970.

-5%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 →
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 →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Green-winged Teal 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 →

No notable trend signals for Green-winged Teal in Wisconsin. See the full index history below.

Green-winged Teal Population Forecast in Wisconsin

If the recent trend holds, Green-winged Teal in Wisconsin is projected to stay roughly flat through 2027, near 0.03 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±79.7%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2027TrendPercent 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 →
0.03Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0995% 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 →
±79.7%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, Green-winged Teal in Wisconsin is projected to stay roughly flat through 2027, near 0.03 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±79.7%, with 100% of held-out values landing inside the 95% band.19662027
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 →
20230.030.000.09
20240.030.000.09
20250.030.000.09
20260.030.000.09
20270.030.000.09

Green-winged Teal Survey Routes in Wisconsin

Routes recording Green-winged Teal 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 →
Dresser320161993
Exeland320192019
Beaver Dam320081993
Minong220212021
Union Twp220171987
Gilman219941994
Washington I219831969
Hatfield219821982
Elderon219851971
Stetsonville220022002
Bayfield119981998
Loraine120091975
Cumberland119931966
Weyerhauser120182018
Mather120101994
Wis Rapids120222022
Stevens Pt120082008
Manawa120041979
Oconto Falls119891989
Omro119931993
Casco120092002
Colby120022002
Gresham120192018
Grimms120022002
Pt Washingtn120081999

Green-winged Teal Population Trend in Other States

alaskaarizonacaliforniacoloradoidahoillinoisindianaiowakansasmainemichiganminnesotamissourimontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-dakotaoklahomaoregonpennsylvaniasouth-dakotatexasutahvermontwashingtonwyoming

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