Carol asked, However, do you make a real distinction between field mice and house mice? In Denmark house mice are field mice that get cold and hungry around late November and move indoors, leave for the fields in March-April. We never have mice in gardens in summertime, as there is so much to eat in the fields. In North America, "house mice" are the introduced European species, dark gray all over. "Field mice" are various native species, particularly the deer mice another correspondent mentioned. Jane McGary