BirdAnalyst
Species · South Dakota · BBS 2026 Release · 1966–2025

American Bittern Population Trend in South Dakota

All statesWetland birds

American Bittern in South Dakota has fallen sharply: down 57% on the route-weighted index since 1969.

-57%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 →
34Routes 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 Bittern 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 →

American Bittern has fallen sharply in South Dakota: down 57% on the route-weighted index since 1969.

American Bittern Population Forecast in South Dakota

If the recent trend holds, American Bittern in South Dakota is projected to rise about 171% by 2030 — from 0.11 in 2025 to a central estimate of 0.29 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±185.6%, with 100% of held-out values landing inside the 95% band.

+171%Change by 2030TrendPercent 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 →
0.29Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.195% 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 →
±185.6%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 Bittern in South Dakota is projected to rise about 171% by 2030 — from 0.11 in 2025 to a central estimate of 0.29 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±185.6%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.310.001.1
20270.310.001.1
20280.300.001.1
20290.300.001.1
20300.290.001.1

American Bittern Survey Routes in South Dakota

Routes recording American Bittern 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 Lake1320111969
Lacreek920231996
Hayes720191996
Crow Creek620191972
Gettysburg420231969
Long Lake420191967
Lane 2420102000
Wilmot320251967
Veblen320221967
Ottumwa320151971
S. Pioneer220241994
Gorman220072007
Turton220192007
Lennox120081974
Tripp120172008
Howard120141971
Geddes119701967
Pioneer120101992
Winner120102010
Volga120171969
Raymond120211967
Roswell119951967
Broadland120121971
Lane119851971
Britton120211967

American Bittern Population Trend in Other States

alaskacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinatexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.