
Based on 5,015 research-grade iNaturalist observations in Pennsylvania, Spicebush Swallowtail is most often recorded in August; in Pennsylvania it behaves like a summer visitor / breeder. It ranks #6 among butterflies recorded in the state in our data.
Papilio troilus
Spicebush Swallowtail in Pennsylvania 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 Pennsylvania in August

Monarch

Eastern Tiger Swallowtail

Zabulon Skipper

Silver-spotted Skipper
Huron Skipper

Black Swallowtail

Pearl Crescent

Peck's Skipper
Places to look in Pennsylvania
Allegheny National Forest
Presque Isle State Park
Jenkins Arboretum
Cherry Springs State Park
Colton Point State Park
Leonard Harrison State Park
FAQ
When does Spicebush Swallowtail appear in Pennsylvania?
Mainly July–August, with the most records in August.
How common is Spicebush Swallowtail in Pennsylvania?
It ranks #6 by number of iNaturalist observations among butterflies in Pennsylvania (5,015 records in our sample).