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

Marsh Wren Population Trend in South Dakota

All statesForest birds

Marsh Wren in South Dakota has surged: up 295% on the route-weighted index since 1969.

+295%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 →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Marsh Wren 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 increasecomputed 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 →

Marsh Wren has surged in South Dakota: up 295% on the route-weighted index since 1969.

Marsh Wren Population Forecast in South Dakota

If the recent trend holds, Marsh Wren in South Dakota is projected to stay roughly flat through 2030, near 2.9 (95% range 1.6–4.1). A 5-year backtest shows a typical error of ±25.9%, with 80% of held-out values landing inside the 95% band.

+6%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 →
2.9Projected 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 →
1.6–4.195% 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 →
±25.9%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, Marsh Wren in South Dakota is projected to stay roughly flat through 2030, near 2.9 (95% range 1.6–4.1). A 5-year backtest shows a typical error of ±25.9%, with 80% 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 →
20262.71.54.0
20272.71.54.0
20282.81.54.0
20292.81.64.1
20302.91.64.1

Marsh Wren Survey Routes in South Dakota

Routes recording Marsh Wren 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 →
Forbes4520251978
Veblen2620231967
Britton2020231984
Volga1720251970
Raymond1520211968
White Lake620111970
Wilmot520251967
Howard420251983
Ft Thompson420022000
Long Lake420191967
Lacreek320181996
S. Pioneer319951995
Turton320252008
Lennox220251967
Roswell220141969
Lane219991999
Tripp120172008
Chamberlain120052005
Broadland120141999
Crow Creek120212010
Ardmore120152015
Long Draw119951995
Lane 2120142002

Marsh Wren Population Trend in Other States

alabamaarizonacaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaslouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-carolinatexasutahvermontvirginiawashingtonwisconsinwyoming

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