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Green Speak

The Mourning Cloak Butterfly

Despite its drab name, the mourning cloak butterfly might be one of spring's earliest flowers. My two sons and I spotted one on a walk along the woods mid-March in 2015. It was resting upside-down sipping away at tree sap along with a flurry of ants. As the butterfly fed, the warm late-winter sun warmed its wings.

With its wings folded the mourning cloak appears relatively unremarkable. As we watched the butterfly's wings spread open my oldest son exclaimed "It's a butterfly!" The dark inner portion of wings contrasts nicely with pale yellow margins. The band of blue dots adds a distinct flair to the butterfly's markings. After snapping several pictures we returned home to learn more about our little friend.

Mourning Cloak (Nymphalis antiopa) is one of the first butterflies to make an appearance in spring. It overwinters as an adult under bark or within tree crevices. The adults mate in spring and females lay their eggs on the twigs of host plants. Caterpillars emerge and live in communal webs in late spring to early summer feeding on the newer leaves of host plants. Host plants for the mourning cloak caterpillar include:

  • black willow (Salix nigra)
  • weeping willow (S. babylonica)
  • silky willow (S. sericea)
  • American elm (Ulmus americana)
  • cottonwood (Populus deltoids)
  • aspen (P. tremuloides)
  • paper birch (Betula papyrifera)
  • hackberry (Celits occidentalis)

Caterpillars pupate and emerge as adult butterflies in June-July. After feeding briefly as adults, the mourning cloak butterfly estivates (similar to hibernation, but in summer) until fall. Feeding resumes in autumn as the butterfly stores energy in preparation for winter hibernation. With a 10 to 11- month adult lifespan, the mourning cloak butterfly may be the longest lived butterfly.

Mourning cloak butterflies have a massive range and are found throughout North America, south of the Canadian tundra, north of Central Mexico and even into temperate Eurasia.

It's amazing what comes from a simple walk through the woods.