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

Northern Rough-winged Swallow Population Trend in North Dakota

All statesAerial insectivores

Northern Rough-winged Swallow in North Dakota has surged: up 109% on the route-weighted index since 1969.

+109%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 →
46Routes 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 North 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 North Dakota: up 109% on the route-weighted index since 1969.

Northern Rough-winged Swallow Population Forecast in North Dakota

If the recent trend holds, Northern Rough-winged Swallow in North Dakota is projected to fall about 27% by 2029 — from 0.56 in 2024 to a central estimate of 0.41 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±28.7%, with 100% of held-out values landing inside the 95% band.

-27%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 →
0.41Projected 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 →
0.00–1.595% 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 →
±28.7%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 North Dakota is projected to fall about 27% by 2029 — from 0.56 in 2024 to a central estimate of 0.41 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±28.7%, 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 →
20250.440.001.5
20260.430.001.5
20270.420.001.5
20280.410.001.5
20290.410.001.5

Northern Rough-winged Swallow Survey Routes in North Dakota

Routes recording Northern Rough-winged Swallow in North 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 →
Rolla1019951978
Lake George519931987
Cooperstown420241970
Tobacco420191970
Horsehead Lk320091993
Dickinson320231968
Dunn Center319961971
Forman220241970
Sydney219791973
Loraine220182016
Stanley220191977
Abercrombie220101969
Denbigh220241968
Lark219861973
Bowman220011970
Gorham220131980
Cedar Creek220161982
Glen Ullin220011982
Wild Rose220241985
Powers Lake220192019
Solen220242006
Walcott120131969
Edgeley120231980
Danzig120091994
Kempton119941969

Northern Rough-winged Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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