BirdAnalyst
Species · Iowa · BBS 2025 Release · 1966–2024

Chimney Swift Population Trend in Iowa

All statesAerial insectivores

Chimney Swift in Iowa has collapsed: down 88% on the route-weighted index since 1969.

-88%Since 1969
39Routes In State
57Years

Notable Chimney Swift Trends in Iowa

long arc declinecomputed index

Chimney Swift has collapsed in Iowa: down 87% on the route-weighted index since 1969.

Chimney Swift Population Forecast in Iowa

If the recent trend holds, Chimney Swift in Iowa is projected to fall about 100% by 2029 — from 1.2 in 2024 to a central estimate of 0.00 (95% range 0.00–2.7). A 5-year backtest shows a typical error of ±28.7%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2029
0.00Projected 2029 index
0.00–2.795% range
±28.7%Backtest error
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 index95% low95% high
20250.620.003.3
20260.460.003.2
20270.300.003.0
20280.140.002.8
20290.000.002.7

Chimney Swift Survey Routes in Iowa

Routes recording Chimney Swift in Iowa.
Desmoines3319791968
Cedar Valley1519971967
Bryant1020241967
Sioux City820241968
West Liberty620231968
Washta620141968
Brooklyn520181967
Maquoketa520231967
Prairieburg420151968
Scranton420101967
Clare420191973
Gaza420181969
Rock Valley420241968
Panther320231967
Alice319961967
Hudson320221967
Dinsdale320051968
Williamsburg220191967
Davis Corner220181968
Burchinal220151999
College Spgs 2220182005
Tipton220211993
Mccallsburg220241996
Mt Hamill120241967
Exline120231974

Chimney Swift Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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