Necrophilic behaviour, corpses as nuclei of resting flock formation, and road-kills of Sand Martins Riparia riparia

Many animal populations are affected by road-kills. In this note I report that corpses of road-killed Sand Martins Riparia riparia attracted conspecifics and thereby increased mortality risk. Close to a lake in northern Greece I observed large numbers of Sand Martins, many of which rested on a road, and seven dead martins were found among them. In six trials I placed the corpses at different places on the road or on a nearby parking area, and in every case new resting flocks of 50-500 individuals formed by the first individuals landing <0.5 m away from the corpses. Further, in each experiment at least 1-5 individuals mounted and attempted to copulate with the corpses. Thus, attraction of conspecifics to corpses, possibly enhanced by necrophilia, may increase rates of road-kills.