Abstract
We analyzed population trends of red foxes (Vulpes vulpes) in Hokkaido, Japan, from the number of foxes observed by spotlight surveys conducted in 1992–2006. The relative abundance indices of foxes in three of six study areas (Abashiri, Tokachi and Konsen) decreased to one-third in the 1990s. We were not able to detect the influence of hunting and food resources on these population declines. Since the timing of the decline in the fox population co-occurred approximately with the outbreak of sarcoptic mange in these areas, we strongly suspect that this epizootic participated in the reduction of fox populations. Though the mange had also spread among foxes in the three remaining study areas (Douhoku, Kamikawa and Hidaka), the relative abundance indices of foxes in these study areas did not decrease, but the cause is unclear.
