Estimating the proportion of various crops in the diet of wild Japanese serow (Capricornis crispus) in Yamagata Prefecture

Abstract

Since the 1970s, Japanese serows have damaged farm crops in the Tohoku region. In Yamagata city, the population of serows has been controlled in order to suppress crop damage and over 300 Japanese serows were culled after 1990. An evaluation of food intake by Japanese serows in cultivated fields can add to a fundamental knowledge for reducing damage to farm crops. Aims of this study were to obtain information on crop damage by Japanese serows by means of questionnaires and traces-eaten and to estimate the amount of crops in their diet. In 1995, farm crop damage by Japanese serows spread over 16.0 ha in Yamagata city. The area of crop damage was the largest in summer (2.5 ha/month). The estimated ingestion of crops was also the highest in summer (731.1 kgDW/month). In the areas where crop damage has occurred constantly and serows have been culled every 2 years, an estimated ingestion of crops per animal was the highest in summer (3.2 kgDW/month/animal). Annual ingestion of crops was 19.6 kgDW/animal. Japanese serow's feeding in cultivated fields was 11.7% in summer and was higher than other seasons. It was 6.9% annually. It is considered that farm crops are not the main foods in the diet of the Japanese serow.