Based on 3,397 research-grade iNaturalist observations in Maryland, Black Swallowtail is most often recorded in August; in Maryland it behaves like a summer visitor / breeder. It ranks #13 among butterflies recorded in the state in our data.
Papilio polyxenes
Black Swallowtail in Maryland 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 Maryland in August
Monarch
Eastern Tiger Swallowtail
Zabulon Skipper
Huron Skipper
Silver-spotted Skipper
Spicebush Swallowtail
Pearl Crescent
Common Buckeye
Places to look in Maryland
State ParkWashington Monument State Park
State ParkPatapsco Valley State Park
State ParkSeneca Creek State Park
State ParkCalvert Cliffs State Park
State ParkSusquehanna State Park
State ParkGambrill State Park
FAQ
When does Black Swallowtail appear in Maryland?
Mainly June–September, with the most records in August.
How common is Black Swallowtail in Maryland?
It ranks #13 by number of iNaturalist observations among butterflies in Maryland (3,397 records in our sample).