Spatio-temporal patterns of vertebrate roadkills in a suburban area in northern Japan

We investigated the roadkills of vertebrates in Ishinomaki City, northern Japan, for 1 full year (from April 2020 to March 2021), and attention was paid to (1) locations where the roadkill occurred, (2) the relationship between roadkill frequency and traffic volume, and (3) seasonality of roadkills and relationship with life events of target species. Over the study period, we recorded 1059 roadkill cases (2.9 records/day) from at least twenty-six vertebrates, among which three mammals (raccoon dog Nyctereutes procyonoides, domestic cat Felis catus, and sika deer Cervus nippon) accounted for more than 75% of the total cases. The locations where frequent roadkills occurred were species-specific as follows: suburban areas for raccoon dogs, within urban areas for cats, and forests, especially peninsula areas, for deer. Roadkill frequency (per kilometer) for raccoon dogs and cats showed a positive correlation with traffic volume, indicating that the prevention of animals from crossing roads would be an effective strategy of mitigating roadkills of these animals. Roadkills of raccoon dogs occurred frequently during fall (September–October), a season that corresponds to their dispersal period. Such seasonality was not found for roadkills of cats (probably due to altered life as pets) and deer (attributed to low seasonal changes in home range utilization). We suggest that management strategies can be adopted to mitigate roadkills from the viewpoint of the behavioral characteristics of target mammals.