BirdAnalyst
Species · South Dakota · BBS 2025 Release · 1966–2024

American Wigeon Population Trend in South Dakota

All statesWaterfowl

American Wigeon in South Dakota has declined: down 49% on the route-weighted index since 1969.

-49%Since 1969TrendPercent 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 →
36Routes 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 →
57YearsYears 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 Wigeon Trends in South DakotaNotable 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 American Wigeon in South Dakota. See the full index history below.

American Wigeon Population Forecast in South Dakota

If the recent trend holds, American Wigeon in South Dakota is projected to rise about 384% by 2029 — from 0.09 in 2024 to a central estimate of 0.44 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±426.5%, with 100% of held-out values landing inside the 95% band.

+384%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 →
0.44Projected 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 →
0.00–1.295% 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 →
±426.5%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, American Wigeon in South Dakota is projected to rise about 384% by 2029 — from 0.09 in 2024 to a central estimate of 0.44 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±426.5%, with 100% 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 →
20250.450.001.2
20260.440.001.2
20270.440.001.2
20280.440.001.2
20290.440.001.2

American Wigeon Survey Routes in South Dakota

Routes recording American Wigeon in South Dakota.
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 →
S. Pioneer1020131995
Cedar Pass520001968
Howard419861986
Pioneer420211993
Britton419841979
Gettysburg419971997
Fort Pierre420181975
Hayes420211995
Indian320211994
Crow Creek320192011
Laplant320111975
Lodgepole320191996
Lennox219801972
Raymond220132009
Railroad Butte220001999
Wilmot219971997
Veblen219841972
Conde219671967
Volunteer220151978
Ottumwa220151967
Reva220241987
White Lake120101977
Chamberlain120112011
Cottonwood120231992
Volga120071967

American Wigeon Population Trend in Other States

alaskacaliforniacoloradoidahokansasmichiganminnesotamontananebraskanevadanew-mexiconorth-dakotaohiooregonpennsylvaniatexasutahwashingtonwisconsinwyoming

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