What Are These
This looks like it could be the activity of some type of animal like squirrels, skunks or raccoons. It usually is just a temporary behavior. After this last bit of winter passes, if you can rake the area lightly and sow some grass seed you should go ahead and do that. If the area is too large to rake you should still take the opportunity to overseed with grass seed. This early in the season the grass should fill in.