Based on 6,527 research-grade iNaturalist observations in Illinois, Eastern Tiger Swallowtail is most often recorded in August; in Illinois it behaves like a summer visitor / breeder. It ranks #4 among butterflies recorded in the state in our data.
Papilio glaucus
Eastern Tiger Swallowtail 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
Monarch
Silver-spotted Skipper
Black Swallowtail
Pearl Crescent
Common Buckeye
Small White
Eastern Tailed-Blue
Hackberry Emperor
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 Eastern Tiger Swallowtail appear in Illinois?
Mainly July–August, with the most records in August.
How common is Eastern Tiger Swallowtail in Illinois?
It ranks #4 by number of iNaturalist observations among butterflies in Illinois (6,527 records in our sample).