Based on 9,509 research-grade iNaturalist observations in Illinois, Great Blue Heron is most often recorded in August; in Illinois it behaves like a summer visitor / breeder. It ranks #7 among birds recorded in the state in our data.
Ardea herodias
Great Blue Heron in Illinois by month
Bars show research-grade observations per month. They mix true seasonality with how often people are outdoors, so treat small numbers with caution.
Also seen in Illinois in August
American Goldfinch
House Sparrow
Ruby-throated Hummingbird
Mallard
Northern Cardinal
Great Egret
Ring-billed Gull
Canada Goose
Places to look in Illinois
State ParkCahokia
Botanical GardenMorton Arboretum
National ForestShawnee National Forest
Botanical GardenChicago Botanic Garden
Botanical GardenLadd Arboretum
State ParkStarved Rock State Park
FAQ
When does Great Blue Heron appear in Illinois?
Mainly April–October, with the most records in August.
How common is Great Blue Heron in Illinois?
It ranks #7 by number of iNaturalist observations among birds in Illinois (9,509 records in our sample).