January: Butterfly of the Month

Mourning Cloak (Nymphalis antiopa )

Alameda Creek is churning through the park this month, swollen with winter rains. Temperatures dip into the 20s and 30s F (below 0 C). But on sunny days, you can find the Mourning Cloak coursing along the banks, usually the only butterfly in sight during this winter month. The Mourning Cloak, which overwinters as an adult, spends the coldest, darkest days tucked into a crack in a tree's bark. With its ashy-brown underside, it goes unnoticed. On the dorsal side, it's a rich velvety brown, edged all around with a band of cream which is bordered by single row of bright blue dots. Mourning Cloak females deposit their eggs in a group, usually in a ring around the stem of a willow, alder, or cottonwood. Arroyo willows grow along the banks of the creek in the park, and the catkins are already visible.

The caterpillars feed on the leaves and form a grayish, spiky chrysalis. In this part of California, the Mourning Cloak is multibrooded. While patrolling for a mate, the Mourning Cloak might investigate your hat or perch on your shoulder. It's a large butterfly, (2 7/8 to 3 1/8 inches -- 73-86 mm)

Other species to look for this month: Satyr Anglewing (Polygonia satyrus). Marilyn once recorded the Satyr Anglewing on Jan. 16.

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