Survival rate and mobility in an enclosed population of red-backed vole, Clethrionomys rufocanus bedfordiae

Survival rate and behavior (mobility) of red-backed voles were investigated from 1978 to 1979 using a one-hectare out-door enclosure in a northern forest in Japan. Sex ratio of new-born young was even, but that in the breeding population deviated toward females. The prevailing female ratio in the breeding population was produced by the two factors: the females matured earlier than the males, and the survival rate of the females was higher than that of the males during maturation.