Abstract
Group size and composition of Sika deer (Cervus nippon) were examined on Kinkazan Island, northeastern Japan, from 1973 to 1977. Mean group size on the island was 3.8 with a range of 1-48. This value was larger than those obtained in other localities of Japan, which was probably due to the more open habitats on the island. Group size was larger in grassland (mean, 4.6 ; range, 1-48) than in woodland (mean, 2.3 ; range, 1-17). Most of the groups (82.4%) were segregated into buck or doe groups. The buck group was smaller in size (mean, 1.7 ; range, 1-7), with solitary bucks occupying 68.0% of the group, while the doe group was larger (mean, 2.9 ; range, 1-23). Seasonal changes were as follows : (1) In spring, the mean group size and the proportion of mixed group increased ; (2) The proportion of doe group increased in summer ; and (3) The proportion of buck group increased in autumn, but since most of the bucks (94.4%) were solitary, the mean size was smallest for the year.
