Milbert's Tortoiseshell

Aglais milberti

Adults hibernate through the freezing winter in hollow trees and sheds, occasionally waking up to bask on unusually warm winter days.

Scientific name: Aglais milberti
Taxonomy: Animalia › Arthropoda › Insecta › Lepidoptera › Nymphalidae › Aglais
IUCN Red List status: Least Concern
Population trend: stable
Biome: forest
Habitat: Moist meadows, forest edges, marshes, and roadsides where stinging nettles are abundant.
Diet: Adults drink nectar from flowers like asters and goldenrod, as well as tree sap. Caterpillars feed exclusively on stinging nettles.
Range: North America, Canada, Northern United States, Rocky Mountains
Size: Wingspan of 4.2 to 6.3 cm (1.6 to 2.5 inches)
Lifespan: Up to 10 months (including adult overwintering)
Active: diurnal
Threats: Pesticide application, habitat destruction, and the widespread eradication of stinging nettles, which are often treated as undesirable weeds.
Safe to approach?: Harmless. You can safely observe this butterfly at close range as it basks or nectars. Avoid touching its wings, as handling can rub off the delicate scales essential for flight. If accidental contact occurs, wash hands before touching eyes.

Aglais milberti , the fire-rim tortoiseshell or Milbert's tortoiseshell , is the only species of Aglais that occurs in North America.

Photo: Matt Muir, CC-BY, via iNaturalist