The Meadow Viper's perspective on the diet and predator-prey interactions of the reptile specialist Smooth Snake

Despite its wide distribution, ecological data on the Smooth Snake (Coronella austriaca) remains limited. Previous dietary analyses report that it mainly consumes lizards, but it also eats mammals and snakes. Little information is available on the habitat choice of the species, but vegetation structure and microtopography are considered the main factors determining occupancy of these snakes. 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 habitats of V. ursinii in Hungary. As there is no data on the occupancy of C. austriaca, we tested if the availability of certain prey species affects its occupancy C. austriaca individuals were captured to collect faecal samples, in which the remains were identified. In the obtained samples (n=53) we found remains of lizards (65%), mammals (20%), insects (12.5%) and Smooth Snake (2.5%). The consumed lizard species were Lacerta viridis, Podarcis tauricus and Lacerta agilis. We found no remains of V. ursinii in the faecal samples. We used dynamic two-species occupancy modeling to test if the occupancy of C. austriaca is linked to the presence of its prey species in the area. We found an interaction between C. austriaca and its lizard prey, as occupancy of C. austriaca had a higher probability when these species were present. We found no interaction between C. austriaca and V. ursinii. Our results support that C. austriaca mainly preys on lizards and its site occupancy depends on prey availability. Importantly, we found no evidence that C. austriaca consumes V. ursinii, which is further supported by the lack of interaction between the occupancy of C. austriaca and that of V. ursinii.