That is a cardboard carton. Oh...and a slug. Does not look like the pictures for mouse droppings. http://www.google.com/search?q=mous...AO45_DgCw&sqi=2&ved=0CCAQsAQ&biw=1020&bih=591 No match for the vole droppings pic. http://www.google.com/search?hl=en&...roppings&btnG=Search&aq=f&aqi=g1g-m1&aql=&oq= How could an animal smaller than a mouse cause that much damage? May I suggest a few glue traps--maybe you would get to see the actual animal. Correct-- don't treat for grubs if its not grubs. I am thinking it is too cold for other insects--however--a large insect like a cutworm sort of fits the dropping size dimension. http://www.extension.umn.edu/distribution/horticulture/m1225.html Cutworms like to eat young seedlings or corn seedlings at this time of year. They are rather nocturnal--so get out there with a flashlight at night and you will probably spot them--or sasquatch or whatever it is. Go with a friend--in case you are attacked.