Abstract
Spatial structure of the grey red-backed vole (Clethrionomys rufocanus bedfordiae) was investigated by using trapping and radiotelemetry methods between April and May 1987 in an enclosure (2.1 ha) in Hokkaido, northern Japan. The locations of home ranges and overlapping patterns of home ranges were not different between trapping and radiotracking. Eight (four pairs) of 15 females showed communal nesting. Three pairs of them had kin-relationship (mother-daughter or siblings) . Communal nesting had been dissolved before the females gave birth to young in two pairs. There were no differences in the pregnancy rate between communal nesting and solitary females, but more parturitions were observed (or estimated) in the communal nesting females. The prolonged association of a male and a female was observed, which had not been reported in this species.
