The Smooth Snake is not a threat to the Meadow Viper: predator-prey interactions of a reptile specialist snake

Ecological data on the Smooth Snake (Coronella austriaca) remains limited. Previous studies report that it mainly consumes lizards, but also mammals and snakes. Its habitat selection remains poorly understood, especially regarding prey availability. As there is limited data on the diet of this species from Central Europe, and it was considered a potential predator of the endangered Vipera ursinii rakosiensis (Hungarian Meadow Viper), we conducted a study concerning the diet of C. austriaca in one of the largest V. ursinii habitats in Hungary. We also tested if the availability of prey species affects its occupancy. Smooth Snake individuals were captured to collect faecal samples, in which the remains were identified. In the obtained samples, we found remains of lizards (65%, namely Lacerta viridis, Podarcis tauricus and Lacerta agilis), mammals (20%), insects (12.5%) and Smooth Snake (2.5%). We found no remains of V. ursinii in the samples. We used two-species occupancy modelling to test if the occupancy of C. austriaca is linked to the presence of prey species in the area. We found interactions between C. austriaca and its lizard prey, as occupancy of the Smooth Snake had a higher probability when these species were present. We found no interaction between the Smooth Snake and V. ursinii. Our results support that C. austriaca mainly preys on lizards and its occupancy depends on prey availability. Importantly, we found no evidence that C. austriaca consumes V. ursinii, further supported by the lack of interaction between the occupancy of C. austriaca and V. ursinii.