Food habits of the Japanese serow (Capricornis crispus) in an alpine habitat on Mount Asama, central Japan

摘要

We investigated the food habits of the Japanese serow (Capricornis crispus) in alpine habitats using direct observations at Mount Asama, central Japan. We observed the feeding behavior of 13 identified adult serows throughout the year, from April 2016 to October 2017. The animals' food habits were evaluated by the feeding probability among 2129 observation bouts. The most important food throughout the year was grasses (feeding probability, 57.6%), followed by forbs (43.5%) and dwarf bamboos (11.4%). However, the feeding probability for each food category drastically changed in relation to the season; in particular, grasses and forbs were especially important foods from spring to autumn, whereas dwarf bamboos and conifers were important in winter. These results suggest that the food habits of the serow are flexible and will vary according to seasonal changes in vegetation. The findings also suggest that the feeding ecology of the serow in an alpine area tends to match that of an intermediate feeder rather than a browser, as was reported by several previous studies conducted in forested habitats. However, the food habits of the serows in the alpine habitats were similar to those of other alpine caprids, such as the mountain goat (Oreamnos americanus), alpine chamois (Rupicapra rupicapra) and Pyrenean chamois (Rupicapra pyrenaica). This is the first study to demonstrate that the food habits of the serow are variable according to the season and/or population. Similar to other alpine caprids, the flexible food habits of the serow in alpine habitats are likely an adaptation to an environment with a characteristically unstable food supply.