1986 Volume 11 Issue 3-4 Pages 93-106
I observed the use of vertical stratification of woods by two species of voles, Clethrionomys rufocanus bedfordiaeandC. rutilus mikado, and by three species of mice, Apodemus speciosus ainu, A. peninsulae giliacusandA. argenteus, in four different types of woods in Hokkaido, Japan. I set containers in the woods inside which a piece of bait was placed, including minute pieces of colored indigestible plastic, which were separated by color in each of four strata (under the litter, on the litter surface, and 50 cm and 150 cm in height above the litter), and at the same time performed live-trapping on the ground surface. All the faeces dropped in traps were then collected and analyzed to estimate the degree of vertical space use. All species but one used all four strata of habitats, but the vertical niche width (H') was narrowest inC. rufocanusand widest inA. argenteus, with subequal and intermediate widths inC. rutilusandA. speciosus. Data ofA. peninsulaewere insufficient to estimate the use of strata. As to habitat preference, C. rufocanusappeared in all four habitats, C. rutilusin three, A. speciosusin two, and the remaining two in one habitat. These trends of habitat preference agreed with those found in Hokkaido to date.