Life-Time Reproductive Success of Female Sika Deer on Kinkazan Island, Northern Japan

Life-time reproductive success (LRS) of female sika deer (Cervus nippon) on Kinkazan Island (9.6 km² in area), northern Japan, was studied based on individually identified females for 17 years from 1989 to 2005. Birth rate was almost zero for females under four years age, while at four it suddenly increased to 39%. Birth rates were about 50% thereafter. Individual females gave birth usually every second year. In the years when mothers were nursing offspring they neither gained body weight nor came into estrus. In the next “yeld” year (no fawn), they came into estrus after gaining body weight. When a mother lost a fawn within 10 days after birth, she recovered body weight. As many as 63% of females died without giving birth to any offspring. A LRS of three offspring was most frequent (16.3%), and more or fewer offspring were less common. No female gave birth to more than six fawns. LRS was greater in longer-living females, and neither concentrating parturition in the prime age classes nor skipping parturition to achieve a longer life was observed. These results seemed to reflect poor food-quality habitat due to the extremely high deer density on the island.