Lifting up a large rock revealed several leafcutter bee nests. They had obviously been made fairly recently as the leaves in one of them (upper right) were still greenish. In the lower left, you can just see another nest case, this one with the leaves completely brown. If you look closely, you can also see a couple of circular pieces of leaf that may have fallen off the one on the left and perhaps another that was just below the left hand one and out of camera range.