Distribution of the field mice Apodemus flavicollis and A. sylvaticus in Norway

Abstract

Examination of specimens of yellow-necked and wood mice in Norwegian museum collections showed that yellow-necked mice are confined to areas with a continental climate, east and northwest of the South Norwegian watershed. The range of wood mice overlapped extensively with that of yellow-necked mice, but contrary to yellow-necked, wood mice also inhabited the most oceanic parts of western and southernmost Norway. Wood mice seem more or less absent in the most continental areas, where yellow-necked mice have their stronghold. Both species are rare in the Trøndelag counties, north of the South Norwegian mountains, and they are absent further north. A discriminant function analysis described the occurrence of yellow-necked mice by low January mean temperatures, low annual precipitation, less productive vegetation zones, and high April temperatures, and wood mice by long growth season and low April temperatures. The analysis alters the Norwegian range maps for both species.