Yellow swallowtails in the northern U.S. are usually born in May.
To get minerals, butterflies drink from mud puddles.
Butterflies are near-sighted, but they can see many more colors than humans can.
The yellow swallowtail was the subject of the first known drawing of a North American butterfly, drawn in 1587.
Butterflies in the stomach is a physical sensation caused by a release of adrenaline, which results in a drop in blood flow. Or you may have had several real butterflies land on your stomach.