21 March 2010
First butterfly of the year
The Mourning Cloak ("Nymphalis antiopa"), known to Brits as the "Camberwell Beauty," is always our first butterfly because it overwinters (probably under loose bark on trees) here in Wisconsin and other northern states, and doesn't need to migrate in from southern climes. At this time of year there are no significant flowers for it to nectar on, so it has adapted by getting nutrition from tree sap. Anyone who has enjoyed maple syrup (Sirop d'Erable) can understand the potential nutritional value of tree sap.
The food plants are in the willow family (willow, poplar, elm, birch), and the caterpillar is known as the "spiny elm caterpillar," feeding gregariously on those trees. I've not been able to locate caterpillars or eggs, so have not raised these, but would love to do so, because they are very handsome creatures.
Photo credit. Distribution map credit.
Update: I wrote this post on April 9 of 2009, and am reposting now because we've already seen our first Mourning Cloak on March 16 this year during a stretch of unusually warm (60+ degree) weather. The following day we saw a thoroughly anomalous appearance of a Cabbage White, which had emerged from an overwintering chrysalis a full month ahead of schedule.