I found dozens of holes in my lawn. What makes them unique is that the grass around each hole is whirled, as if my lawn has been invaded by dozens of tiny tornadoes! MY property backs up to woods, and there's a stream running through the property near the woods.
This could be skunks looking for grubs. You may see the same phenomenon in spring when grubs migrate to the surface as the soil warms. There are numerous control suggestions on the web. Whether they actually work or just keep getting repeated, I don't know.