Comparing the effectiveness of two roadkill survey methods on roads

•Aim: Are roadkill surveys conducted by road patrol officers effective?•Method: Comparison of the number of species by size and location, and the number of roadkill hotspots, between those recorded by daily surveys conducted by patrol agents, and those conducted on a monthly basis by an ecologist.•Results - Discussion: Patrol officers collected more roadkills (all large and few small species) than the ecologist (who collected few large and more small species). There was no significant difference in the location of main roadkill hotspots.•Conclusion: Both methods are complementary and can be combined to obtain more representative data. Wildlife-vehicle collisions on linear transport infrastructure and especially on roads are potentially dangerous for drivers and cause serious economic damage. Moreover, roads cause fragmentation, creating barriers or traps that are harmful to many animal species, underlining the need to detect roadkill hotspots. However, the effectiveness of some roadkill survey methods on roads is not fully understood. The aim of this study is to conduct comparative analyses of the spatial distribution, body size totals and composition of roadkill hotspots, using data collected in a study area using two robust roadkill survey methods: i) one conducted monthly by an ecologist, ii) one conducted daily by patrollers. The results suggest that these methods are efficient in locating mortality hotspots and are complementary: they identify different body size groups, with patrollers detecting all large fauna and ecologists recording more small species. We suggest combining both methods to obtain more representative data of road mortality.