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

Great Crested Flycatcher Population Trend in Illinois

All statesAerial insectivores

Great Crested Flycatcher in Illinois has surged: up 122% on the route-weighted index since 1968.

+122%Since 1968
104Routes In State
58Years

Notable Great Crested Flycatcher Trends in Illinois

long arc increasecomputed index

Great Crested Flycatcher has surged in Illinois: up 122% on the route-weighted index since 1968.

Great Crested Flycatcher Population Forecast in Illinois

If the recent trend holds, Great Crested Flycatcher in Illinois is projected to fall about 19% by 2029 — from 3.5 in 2024 to a central estimate of 2.9 (95% range 1.9–3.9). A 5-year backtest shows a typical error of ±28.6%, with 40% of held-out values landing inside the 95% band.

-19%Change by 2029
2.9Projected 2029 index
1.9–3.995% range
±28.6%Backtest error
19662029
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
20252.81.83.8
20262.81.83.8
20272.81.83.8
20282.91.83.9
20292.91.93.9

Great Crested Flycatcher Survey Routes in Illinois

Routes recording Great Crested Flycatcher in Illinois.
Bremen2320241969
Belknap2120241970
Royalton2020242003
Belleview1820241966
York1520241993
Beaverdam Lk1420231970
Eubanks1220242001
Mascoutah Lk1020241970
Pulaski1020241970
Payson1020242000
Sandusky820231993
Marshall820242001
Terre Haute720241966
Monica720161973
St Morgan720221968
Janesville620231979
Bradbury620241971
Olney620241966
Robinson620231970
Alden620232019
Allerton Park620232003
Mill Creek520241967
Buda520221977
Stillwell520231971
Bartonville520241973

Great Crested Flycatcher Population Trend in Other States

alabamaarkansascoloradoconnecticutdelawarefloridageorgiaindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawest-virginiawisconsin

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