A Sika deer (Cervus nippon) population had been maintained at a level
of around 600 head on Kinkazan Island (960 ha), northern Japan during
the 1970s and the early 1980s. However, in the spring of 1984 which fo
llowed an uncommonly cold winter, a mass-mortality occurred and about
half of the deer population died. A total of 293 recovered carcasses i
ndicated that many had died during a short period (late March and mid-
April). More carcasses were found in the lower altitudinal areas than
expected numbers relative to area sizes, suggesting that the deer had
moved down from the higher areas to avoid snow. Rumen contents of the
carcasses contained much low quality food. Malnutrition caused by the
exceptional coldness and late snow was considered to be the factor res
ponsible for mortality.