I heard it before I saw it, that persistent tap tap tap of a bird, a Song thrush, dashing a snail against a stone, its anvil, to free the shell of its juicy contents. I’ve read that thrushes often use the same stone over and over and, when I found this particular stone, I could certainly believe it. Just look at all those broken snail shells. It’s sad for the snails but good for the Song thrush and its offspring.