抄録
It is well known that the number of individuals of the Cervus species sometimes extends beyond a reasonable population size based on the environmental conditions. Then, they resulted in a mass die-off for the adjustment of population size under severe circumstances. The present work was mainly conducted to demonstrate the population dynamics of Cervus nippon located at the Ashio mountains, Tochigi Pref., under a heavy snow condition during the winter of 1984. As a result, several types of unusual movements were observed in the population. With the snow, the habitable environment was limited into a more narrow range of space. At a highest extreme, the population reached 121.8 individuals per square kilometer. Corpses were discovered first in the middle of March, reaching at a highest rate of about 36% in the end of this month. Most of the individuals to die were yealings first, followed by adolescents, and male and female adults.
