BirdAnalyst
Species · Wisconsin · BBS 2026 Release · 1966–2025

Chimney Swift Population Trend in Wisconsin

All statesAerial insectivores

Chimney Swift in Wisconsin has declined: down 49% on the route-weighted index since 1968.

-49%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 →
96Routes 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 Chimney Swift 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 Chimney Swift in Wisconsin. See the full index history below.

Chimney Swift Population Forecast in Wisconsin

If the recent trend holds, Chimney Swift in Wisconsin is projected to fall about 13% by 2030 — from 2.9 in 2025 to a central estimate of 2.5 (95% range 0.60–4.5). A 5-year backtest shows a typical error of ±40.9%, with 100% of held-out values landing inside the 95% band.

-13%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 →
2.5Projected 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 →
0.60–4.595% 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 →
±40.9%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, Chimney Swift in Wisconsin is projected to fall about 13% by 2030 — from 2.9 in 2025 to a central estimate of 2.5 (95% range 0.60–4.5). A 5-year backtest shows a typical error of ±40.9%, with 100% 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 →
20262.70.764.6
20272.70.724.6
20282.60.684.6
20292.60.644.5
20302.50.604.5

Chimney Swift Survey Routes in Wisconsin

Routes recording Chimney Swift 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 →
Gresham1920251998
Omro1620011966
Stevens Pt1420131967
Mukwonago 21420252005
Manitowoc1320231966
Holland1220251998
Weyerhauser1120251966
Pardeeville1120251968
Pt Washingtn1120241966
Raymond1020251966
Grimms1020211998
Kiel1020251998
N Freedom920251966
Hebron920251966
Gilman820251966
Brownsville820251966
Stetsonville820251990
Mukwonago820041998
Rib Lake720251966
Merrill720251966
Mount Horeb719901967
Iron River620241967
Cochrane620251967
Trempealeau620251966
Casco620251972

Chimney Swift Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawyoming

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