It's a little hard to see but there is a trail worn into the ground here. It runs right past the stone and between the two tufts of grass, from our shed to the steps leading onto our back deck, on the railing of which is perched our squirrel feeder. There has been a squirrel apparently living under our shed for most of the past year. I think it is probably very near to where the compost pile is. It would be a good warm spot. We saw a trail in the snow frequently over the winter but I never would have guessed that such a tiny creature could make a noticeable trail across the gravel even making the dozens of trips a day we see.