I claim the ornamental design for a head covering, as shown and described.
FIG. 1 is a front elevation view of a head covering showing my new design;
FIG. 2 is a back elevation view of the head covering of FIG. 1;
FIG. 3 is a left side elevation view of the head covering of FIG. 1;
FIG. 4 is a right side elevation view of the head covering of FIG. 1;
FIG. 5 is a top plan view of the head covering of FIG. 1;
FIG. 6 is a bottom plan view of the head covering of FIG. 1;
FIG. 7 is a left side perspective view of the head covering of FIG. 1, shown in use;
FIG. 8 is a left side perspective view of the head covering of FIG. 1, shown in use;
FIG. 9 is a left side perspective view of the head covering of FIG. 1, shown in use; and,
FIG. 10 is a left side perspective view of the head covering of FIG. 1, shown in use.
The broken line outline of the partial human figure in FIG. 2 and FIGS. 7-10 assists in illustrating how the head covering may appear when worn, but forms no part of the claimed design.