A Satyr Angelwing butterfly (Polygonia satyrus) warms itself by basking on the sunny side of an aspen tree. These butterflies feed on tree sap more than flower nectar, and their eggs and caterpillars rely almost exclusively on thistle plants.
A caterpillar formed the chrysalis, but a brand new Mourning Cloak butterfly emerged from it a few weeks later. Her new wings are wrinkled at first, so she must hang upside-down to let her wings unfold and harden for an hour. Only then will she make her very first flight.
The Mourning Cloak is Montana's state butterfly. They overwinter as adults, like this one, and then mate and lay eggs in the spring.