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

Blue-winged Teal Population Trend in South Dakota

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Blue-winged Teal in South Dakota has fallen sharply: down 56% on the route-weighted index since 1969.

-56%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 →
51Routes 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 Blue-winged Teal 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 →

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 →

Blue-winged Teal has fallen sharply in South Dakota: down 56% on the route-weighted index since 1969.

Blue-winged Teal Population Forecast in South Dakota

If the recent trend holds, Blue-winged Teal in South Dakota is projected to fall about 13% by 2029 — from 4.5 in 2024 to a central estimate of 4.0 (95% range 0.00–9.5). A 5-year backtest shows a typical error of ±41.4%, with 100% of held-out values landing inside the 95% band.

-13%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 →
4.0Projected 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 →
0.00–9.595% 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 →
±41.4%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, Blue-winged Teal in South Dakota is projected to fall about 13% by 2029 — from 4.5 in 2024 to a central estimate of 4.0 (95% range 0.00–9.5). A 5-year backtest shows a typical error of ±41.4%, 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 →
20254.20.009.8
20264.10.009.7
20274.10.009.7
20284.00.009.6
20294.00.009.5

Blue-winged Teal Survey Routes in South Dakota

Routes recording Blue-winged Teal 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 →
White Lake5620111967
Conde3719841967
Forbes3420241967
Long Lake3020191967
Raymond2620211967
Cottonwood2120241993
Roswell1520141967
Wilmot1520241967
Eagle Butte1320152002
Promise1220151971
Gettysburg1020231969
Reva1020191979
Gorman920101995
Indian920241994
Volga820241967
Veblen820231967
Lane 2720132000
Lodgepole620221995
Tripp420231967
Chamberlain420111972
Pioneer420241993
Britton420231967
Cedar Pass420211967
S. Pioneer420241995
French Creek420031995

Blue-winged Teal Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawarefloridaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandtennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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