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

Lesser Scaup Population Trend in South Dakota

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Lesser Scaup in South Dakota has edged down: down 21% on the route-weighted index since 1969.

-21%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 →
23Routes 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 →
44YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Lesser Scaup 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 Lesser Scaup in South Dakota. See the full index history below.

Lesser Scaup Population Forecast in South Dakota

If the recent trend holds, Lesser Scaup in South Dakota is projected to fall about 28% by 2024 — from 0.46 in 2019 to a central estimate of 0.33 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±357.5%, with 100% of held-out values landing inside the 95% band.

-28%Change by 2024TrendPercent 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 →
0.33Projected 2024 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 →
±357.5%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, Lesser Scaup in South Dakota is projected to fall about 28% by 2024 — from 0.46 in 2019 to a central estimate of 0.33 (95% range 0.00–1.2). A 5-year backtest shows a typical error of ±357.5%, with 100% of held-out values landing inside the 95% band.19672024
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 →
20200.340.001.2
20210.340.001.2
20220.340.001.2
20230.330.001.2
20240.330.001.2

Lesser Scaup Survey Routes in South Dakota

Routes recording Lesser Scaup 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 River1019971997
Long Lake920191967
Forbes620151979
Gettysburg620002000
Owanka619931993
Harding419971968
Lennox319741974
Volga220191967
Wilmot220102010
Veblen219791979
Britton220111978
Ottumwa219971987
Reva220191995
Howard120042004
White Lake120102010
Cottonwood119971995
Winner120192019
Crow Creek120052005
Conde119691967
Cedar Pass119911991
Fort Pierre120151971
Lodgepole120192019
Ardmore119961978

Lesser Scaup Population Trend in Other States

alaskacaliforniacoloradoidahoiowakansasmichiganminnesotamontananebraskanevadanew-mexiconorth-dakotaoregonutahwashingtonwisconsinwyoming

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