Age distribution, sex ratio and mortality of the red fox Vulpes vulpes in Tochigi, central Japan: an estimation using a museum collection

Abstract

AbstractOne hundred and thirty carcasses of the red fox were collected in Tochigi Prefecture, by the Tochigi Prefectural Museum, from 1981 to 1991. The young/adult ratio of the sample was 1.60, which suggests that the hunting pressure has been relatively low in this area. Six percent of the animals were 5 years or older which compares to those taken in Hokkaido, but is higher than those in Europe and North America. The sex ratio for all specimens had a tendency towards male bias (0.587), but this bias was higher for the adult (0.605) than for the young (0.576). Among young (0 year‐old) foxes, more individuals were killed on roads than by trapping or shooting (P<0.02, chisquare test). This mortality pattern was caused by high mortality of young males (P<0.02). The proportions of adults killed by the three mortality factors were similar, though only one of the 14 foxes older than 4 years old was shot, probably due to age‐linked activity patterns. Most road‐kills of young foxes occurred in May when juveniles began exploiting and in November when sub‐adults began dispersal. The ratios of road‐kills for the whole sample and for adults alone were 42% and 34%, respectively. These high rates of road‐kills suggest that the mortality pattern in Tochigi has been affected by factors characteristic of urban environments.