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

Northern Rough-winged Swallow Population Trend in South Dakota

All statesAerial insectivores

Northern Rough-winged Swallow in South Dakota has surged: up 219% on the route-weighted index since 1969.

+219%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 →
50Routes 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 Northern Rough-winged Swallow 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 →

Northern Rough-winged Swallow has surged in South Dakota: up 219% on the route-weighted index since 1969.

Northern Rough-winged Swallow Population Forecast in South Dakota

If the recent trend holds, Northern Rough-winged Swallow in South Dakota is projected to rise about 34% by 2029 — from 0.91 in 2024 to a central estimate of 1.2 (95% range 0.00–3.7). A 5-year backtest shows a typical error of ±282.7%, with 100% of held-out values landing inside the 95% band.

+34%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 →
1.2Projected 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 →
0.00–3.795% 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 →
±282.7%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, Northern Rough-winged Swallow in South Dakota is projected to rise about 34% by 2029 — from 0.91 in 2024 to a central estimate of 1.2 (95% range 0.00–3.7). A 5-year backtest shows a typical error of ±282.7%, 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 →
20251.20.003.7
20261.20.003.7
20271.20.003.7
20281.20.003.7
20291.20.003.7

Northern Rough-winged Swallow Survey Routes in South Dakota

Routes recording Northern Rough-winged Swallow 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 →
Geddes10020221967
Custer4520121979
Owanka1419941968
Cedar Pass820021977
Lodgepole820241996
Reva620221979
Lennox520241967
Lane519861977
Chamberlain420061968
Forbes420111970
Marcus420021999
Wind Cave Np420242003
Rockyford320131968
Volga320071976
Crow Creek320231968
Tripp220231985
Rosebud219891967
Raymond220111983
Roswell219921972
Ft Thompson220031968
Veblen220121973
Britton220221973
Promise220001972
Volunteer219881968
Maurine220241968

Northern Rough-winged Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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