Milbert’s Tortoiseshell (Aglais milberti)
… is one of a number of butterfly species that overwinter as adults. They emerge in the first warm days of spring (or sometimes, mistakenly, during very mild spells in mid-winter), as early as late February in southern parts of its range. It’s found throughout most of the west, but in the east only occurs in Canada and the northern states.
Adults are nectar feeders; in the early spring when flowers are scarce, they will also drink from sap wells/leaks on trees. They can often be spotted visiting willow flowers, as seen here. The caterpillars feed on species of Urtica - stinging nettle. The pattern on the adult’s wings resembles a cat’s face, and is probably used to startle predators the same way large owl-eye spots on some other species do.
photo by Brad Smith (BugMan50) on Flickr
(via: Peterson Field Guides)