Appearance: Short projections on both wings, borders irregular. Above, forewing and hindwing an intense rusty brown with broad yellow borders on outer margins, and a row of iridescent blue spots at the inner edge of the border.  Below, a blackish brown color with striations and a paler border. The underside provides excellent camouflage when pressed against the trunk of a tree.

Wingspan: Large; 2 1/4 to 4 inches.

Habitat: A wide variety of habitats including woods, fields, meadows, parks, gardens, riparian areas, suburbs and cities; plains, foothills, montane.

Flight Times: Normally March to mid-September, but any month of the year is possible. (An early December sighting reported in Boulder, 2010 and possible during a warm snap in January and/or February).

Larval Foodplant: Depending on altitude, aspen, birch, willow, or at lower elevations cottonwood, elm, or hackberry.

Did You Know…
Mourning Cloaks overwinter as adults, emerge in the spring; females lay eggs in groups circling twigs of host plant.  Caterpillars live in communal web and feed together, pupate, and emerge in midsummer, and possibly estivate during the heat of summer to fly one last time in the fall before they hibernate. It is sometimes possible to see fresh, newly emerged, adults flying in the fall with last year’s tattered and soon to expire adults that overwintered the previous year.

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