Even though there is no visible puddle in this image, this butterfly is "puddling" or drinking in moisture and minerals from the moist soil. We found butterflies doing the same thing at animal scat in the forest. On one day hike we passed a fresh pile of scat with several different types of invertebrates at it on the way out, and on the way back several hours later, the pile was completely gone save for a moist spot on the ground where a few butterflies lingered.