The Maze in the Grass

In one of my blogs last week I presented a couple of mysterious pictures (one, two, three) taken in the grass near where I live. I had first seen the phenomena when I was growing up and this was the first time I had seen it in Ottawa. The picture is of mouse trails and tunnels in the grass and dirt. When a thick crust of snow forms mice burrow and hibernate underneath it eating the grass, weed and worms. Rather than stay in once place they dig through the grass and soil to form a maze that they can run through to keep warm and to expand their feeding ground.