Mourning cloak (Nymphalis Antiopa) behavior and ecology

[Paul Cherubini]

University of California at Davis Professor Arthur M. Shapiro has found
Mourning Cloaks overwintering inside empty beer cans, buried deep under
the snow, at Donner Summit in the Sierra Nevada Range. There is
currently 12 FEET on snow on the ground at Donner Summit.  Roadside
litter may be an eyesore to humans, but to Mourning Cloaks...

Paul Cherubini, El Dorado, California