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Species · Wisconsin · BBS 2026 Release · 1966–2025

Northern Rough-winged Swallow Population Trend in Wisconsin

All statesAerial insectivores

Northern Rough-winged Swallow in Wisconsin has declined: down 40% on the route-weighted index since 1968.

-40%Since 1968TrendPercent 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 →
91Routes 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 →
59YearsYears 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 WisconsinNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Northern Rough-winged Swallow in Wisconsin. See the full index history below.

Northern Rough-winged Swallow Population Forecast in Wisconsin

If the recent trend holds, Northern Rough-winged Swallow in Wisconsin is projected to rise about 104% by 2030 — from 0.65 in 2025 to a central estimate of 1.3 (95% range 0.24–2.4). A 5-year backtest shows a typical error of ±110.7%, with 80% of held-out values landing inside the 95% band.

+104%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 →
1.3Projected 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 →
0.24–2.495% 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 →
±110.7%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 Wisconsin is projected to rise about 104% by 2030 — from 0.65 in 2025 to a central estimate of 1.3 (95% range 0.24–2.4). A 5-year backtest shows a typical error of ±110.7%, with 80% of held-out values landing inside the 95% band.19662030
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 →
20261.40.272.4
20271.30.262.4
20281.30.262.4
20291.30.242.4
20301.30.242.4

Northern Rough-winged Swallow Survey Routes in Wisconsin

Routes recording Northern Rough-winged Swallow in Wisconsin.
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 →
Eagle River1820111971
Cochrane1420221966
River Falls1220221998
Esdaile1020251966
Clintonville920181972
Hazel Green720181967
Trempealeau620251966
Verona620231991
N Freedom520251970
Pardeeville520211980
Highland520211999
Popple River420221969
Elderon419981967
New Lisbon420171967
Wiota420251966
Cavour420212000
Kiel420221998
Mukwonago420032000
Grand View319861972
Couderay320161969
Wausaukee320161986
Princeton320171974
Stetsonville320041997
Weirgor Springs320162009
Gresham320181998

Northern Rough-winged Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawyoming

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