Male Woodpeckers Incubating at Night

When they come in the yard, I notice a habit which I have not seen mentioned in any of the literature. Almost every night that they are present he birds from time to time alight on the bare spots near the foundations of the house, where they creep about over the red clay, and apparently pick up grit. (Upon investigation I found no ants br other insects on the ground.) Sometimes a bird will chuckle softly while doing this. Furthermore, on these occasions I have never seen them take dust baths. This action of the birds is so common here that I thought it worthy of record.--GoR•oN W. JoNEs, Wilderness, Virginia.