New Jersey Butterflies

Milbert's Tortoiseshell

Nymphalis milberti

Identification: Small—1.8" (much smaller than Compton Tortoiseshell). Above: FW and HW dark brown but with a brilliant yellow and burnt orange "sunburst" band near margin of both wings. Unmistakable and unforgettable. Below: FW and HW two-toned—basal area finely striated dark brown, outer portion paler and also finely striated, with a narrow blue line paralleling the irregular wing edges. Less mottled-looking below than Compton Tortoiseshell.

NJ Status and Distribution: Sporadic resident. Primarily a northern species that is of very irregular occurrence in NJ. Perhaps our most boom-and-bust resident species. The last big outbreak began quietly in 2001 and persisted to 2008.

NJ Range Map-Milbert's Tortoiseshell

Habitat: Flowery meadows and fields with the host plant. Often seen on bare ground like Compton, anglewings, and Mourning Cloaks.

Flight Period: Overwintering adults begin flying by the end of April. Their offspring emerge in July and fly into November. During outbreaks most often reported in April into May; July; and September/October.

Larval Food Plants: Nettles in the genus Urtica.

Overwintering Stage: Adult.

Best Locations: During the last outbreak was most common in the Delaware Water Gap NRA and Wallkill River NWR.

Comments: Because the host plant is always common and widespread in NJ, it is a mystery why colonies disappear after a few years.

Milbert's Tortoiseshell

Macricostas Reserve, CT, 6/10/07.

Milbert's Tortoiseshell

Walpack, Sussex Co., NJ, 6/8/04.

Stinging Nettle

Stinging Nettle (Urtica dioica) and the very similar Tall Nettle (U. procera) are two important host plants for Eastern Comma, Milbert's Tortoiseshell, and Red Admiral.