Hibernating comma

These are not recent photos but were taken in February two years ago.  I felt it worth posting them as it was a rare sighting (for me) of a hibernating comma butterfly.  It is head down on a tree trunk and matches the peeling birch bark perfectly.  The comma gets its name from the small c-shaped white mark on the underside of the wings as seen well here (hence also its latin name Polygonia c-album).  The comma is unusual in overwintering as an adult.  It hibernates from November to April.

This is for Sophie who thought a hibernating comma must be an exotic punctuation mark!