I photographed this Mourning Cloak butterfly (Nymphalis antiopa) on San Juan Island in Washington on 25 May 2013.
Mourning Cloaks are often associated with willows, and sure enough, we found several of them basking in the sun near a willow thicket. A few were also sipping sap from the bark (next image).
Note that the undersides of their wings are very different than the uppersides — predominantly black and charcoal gray with a golden border.
There are quite a few willow thickets on Bodega Head and I've often thought those sites would be good places to find Mourning Cloaks. I haven't found one yet, and it's actually been a bit of a mystery why I haven't seen Mourning Cloaks locally. Are they just not common along the Sonoma Coast?
But recently, in A Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions, I read a reference to Mourning Cloaks undergoing a "catastrophic regional population collapse, disappearing from many places and becoming very rare in others." And it sounds like this may have happened in the early 2000s. So now I'm wondering if I arrived in this area at a time when Mourning Cloaks are harder to find...or if they've always been rare (or unrecorded) on Bodega Head? If you are familiar with their status in this area, I'd love to hear more!