Movement on canopy and ground of Japanese squirrels

Abstract

Canopies are an important habitat for arboreal mammals. It is necessary to clarify the movement paths in order to prevent habitat decline. From February 29 1984 to September 1 1986, I recorded each tree as used for movement paths of 13 Japanese squirrels (Sciurus lis, 6 males and 7 females) by the direct observation method. These squirrels were introduced on a trial basis to Shinjuku Gyoen National Garden on February 23 1984. The squirrels used 372 trees in 112 movement paths, of these, 96 trees (25.8%) were used more than once. The movement paths were built of trees that were used for feeding and nesting. In 78 of the 112 movement paths, individual squirrels using movement paths can be identified by color-marked collars. In addition, 56 movement paths (71.8% of 78 movement paths) included the same trees or consecutive trees. Different individuals used the same movement paths ; therefore, squirrels shared the same movement path regardless of sex. In the park area of Chiba prefecture, 40% of 47 movement cases on the ground were in a distance of 4-10m and 30m at maximum.