Aglais (Nymphalis) milberti
Very rare in south-western Ontario, with a few recorded at Point Pelee, intermittently throughout the years, but it is a permanent resident in central and northern Ontario. They prefer wet areas and marshes. Caterpillars feed on nettles Urtica.
While in Stratford waiting to see a play, this one was found in the Shakespeare Garden on an exotic unknown shrub, too high to get a photo of the top side.
Adults prefer sap and rotting fruit, and occasionally nectar from flowers. Females lay a massive number of eggs on the underside of nettle leaves, and like the Mourning Cloak, the caterpillars all stay together when young. They can have up to 3 generations a year. Adults hibernate during the winter.