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

Ruddy Duck Population Trend in South Dakota

All statesWaterfowl

Ruddy Duck in South Dakota has fallen sharply: down 51% on the route-weighted index since 1970.

-51%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 →
30Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ruddy Duck 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 →

Ruddy Duck has fallen sharply in South Dakota: down 51% on the route-weighted index since 1970.

Ruddy Duck Population Forecast in South Dakota

If the recent trend holds, Ruddy Duck in South Dakota is projected to rise about 788% by 2029 — from 0.09 in 2024 to a central estimate of 0.81 (95% range 0.00–3.6). A 5-year backtest shows a typical error of ±241.3%, with 100% of held-out values landing inside the 95% band.

+788%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 →
0.81Projected 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 →
0.00–3.695% 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 →
±241.3%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, Ruddy Duck in South Dakota is projected to rise about 788% by 2029 — from 0.09 in 2024 to a central estimate of 0.81 (95% range 0.00–3.6). A 5-year backtest shows a typical error of ±241.3%, 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 →
20250.860.003.7
20260.840.003.7
20270.830.003.6
20280.820.003.6
20290.810.003.6

Ruddy Duck Survey Routes in South Dakota

Routes recording Ruddy Duck 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 →
Forbes2120211978
Pioneer2019961992
Broadland2020092001
Long Lake1620191967
Crow Creek1320102010
White Lake1120111967
Laplant520151999
Ottumwa519771972
Lennox420081973
Raymond420212005
Harding420021982
Cottonwood320231992
Conde319671967
Wilmot220192019
Britton220231967
Gettysburg220111996
Cedar Pass220211991
Fort Pierre220061998
Reva220092009
Lacreek220232019
Tripp120081986
Howard120241986
Volga120191969
Roswell120121983
S. Pioneer120241995

Ruddy Duck Population Trend in Other States

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