One thing with geese they are digger's and love to eat dirt! Guess it has minerals in it that they need. Also when it rains they love digging the mud and love making holes and the water get in it and the play and dig deeper holes. They seem to get their beaks into everything. So no matter how hard you try they will always find something digging in the ground.
The person who owned this place before us I do believe like to burry things here. We have found so many things here when we start digging around it is not even funny on how much crap he buried or the people before who lived on this land.... There is always something to pick up to keep the geese safe here.