A preliminary survey on nest cavity use by Siberian flying squirrels, Pteromys volans orii, in forests of Hokkaido Island, Japan

Abstract

Pteromys volans orii, which is an endemic subspecies to Hokkaido Island, Japan, is arboreal and usually nests in cavities in trunks. To broadly understand what nest cavity is selected by P. volans orii in mountainous areas, we preliminary surveyed cavity resources in natural forests of Hokkaido. All nest cavities were on live-trees. Most of them were naturally formed after branches fall from the tree. These findings seem to be specific to Hokkaido population. Longest diameter of nest cavities was significantly shorter than that of unused cavities. This suggests that P. volans orii may select cavities with smaller entrances to avoid predators. The nest tree species most frequently used by this subspecies was Abies sachalinensis, which is most dominant in mountainous forests of Hokkaido. A. sachalinensis would provide abundant nest resources for P. volans orii.