Rare, iridescent butterfly spotted in a Delaware swamp

There are 120 species of butterfly that live and breed in Delaware, according to The Nature Conservancy. The list just grew by one more.

The tiny Hessel’s Hairstreak butterfly is about as big as your thumb, with a wingspan of barely an inch. Its wings shimmer with iridescent flecks of emerald green against brown. It is extremely rare, living almost exclusively in Atlantic white cedar swamps.

The hairstreak has not been spotted on the Delmarva Peninsula since 1995, when Dr. Christopher Heckscher, an entomologist with Delaware State University, spotted one. He was surprised to see it again 27 years later, on land protected by The Nature Conservancy in southern Delaware.

“I consider it one of the region’s most important Lepidoptera conservation targets,” said Heckscher. “It would be the only known population between New Jersey and southeastern Virginia.”

The Hessel’s Hairstreak, named in honor of lepidopterist Sidney Hessel, is considered an endangered species in Delaware. For security reasons, the Nature Conservancy is not disclosing the location of the sighting, but said the survival of the species is possible due to protected natural land.