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

Cliff Swallow Population Trend in Illinois

All statesAerial insectivores

Cliff Swallow in Illinois has surged: up 179× on the route-weighted index since 1969.

179×Since 1969
95Routes In State
56Years

Notable Cliff Swallow Trends in Illinois

long arc increasecomputed index

Cliff Swallow has surged in Illinois: up 179× on the route-weighted index since 1969.

Cliff Swallow Population Forecast in Illinois

If the recent trend holds, Cliff Swallow in Illinois is projected to fall about 17% by 2029 — from 19 in 2024 to a central estimate of 16 (95% range 10–21). A 5-year backtest shows a typical error of ±24%, with 60% of held-out values landing inside the 95% band.

-17%Change by 2029
16Projected 2029 index
10–2195% range
±24%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
2025149.119
2026159.420
2027159.820
2028151020
2029161021

Cliff Swallow Survey Routes in Illinois

Routes recording Cliff Swallow in Illinois.
Greenview23020242000
Eldred15720211993
Chandlervill9620242013
Sheffield8920241989
Lake Galena7420212001
Fairdale7420242021
Holcomb7120241989
Beaverdam Lk6920231980
Belleview6120241974
Terre Haute6020241980
Deer Creek5520242003
Geneseo5220211969
Duncan Mills5120242016
Brnt Prairie4620242006
Sherrard4520241998
Le Roy3320241994
Atkinson3220241976
Buda3220231992
Williamsfld3220241992
Fairland3220242000
Guilford3020231977
Mackinaw2620241999
Shannon2320241993
Bartonville2020242001
Milford2020231972

Cliff Swallow Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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