The Collaborative International Dictionary
campagnol
fieldmouse \fieldmouse\, field mouse \field mouse\n.
(Zo["o]l.) any nocturnal Old World mouse of the genus Apodemus inhabing woods and fields and gardens.
(Zo["o]l.) any mouse inhabiting fields, as the campagnol and the deer mouse. See Campagnol, and Deer mouse.
Wiktionary
campagnol
n. (context archaic English) A mouse (''Arvicala agrestis'') that often does great damage in fields and gardens, by feeding on roots and seeds.