Abstract
The scat contents of feral dogs (Canis familiaris) were compared between two periods (1973-1975 and 1993-1994) before and after an increase of sika deer population in Nikko, central Honshu, Japan. Among five food items, sika deer (Cervus nippon) was found to be the main staple food during both periods. In the first period, before the population increase of sika deer, however, the occurrence of sika deer in scats decreased from 66% in winter and spring to 19% in summer and fall, next to human leftovers. In the second period after the recent population increase of sika deer, sika deer comprized 78-96% and was ranked at the top throughout the year, while human leftovers declined to only several percent. Thus, sika deer and human leftovers were likely in a trade-off relation. Small mammals occupied a small portion. Natural plant fractions may have been eaten with the digestive organs of sika deer.
