Comparing day and night predation rates on lizard-like clay models

Clay models of live animals are often used by behavioral ecologists and ethologists to study prey-predator interactions under field conditions. This technique has limitations, however, and often models are displayed in the field for long periods of time without distinguishing between daytime and nighttime attacks. We compared day and night predation rates on lizard-shaped clay models in a temperate ecosystem in northwest Italy. We placed 206 lizard models in two adjacent habitats (i.e., a mixed broadleaf woodland and along an adjacent ecotone) and checked them every morning and evening for three consecutive days (i.e., for 72 h). The model head was attacked more than expected by chance, indicating that predators were perceiving the models as true prey items. The overall observed predation rate was 18% (39/206) and was similar between the two habitats; however, models were attacked more than twice as often during daytime versus nighttime with 28 attacks (71%) during the day and 11 attacks (29%) during the night. Mammal predators attacked the models with similar frequencies during both daytime and nighttime. These findings indicate that, at least in our study area, the predation rate on terrestrial lizards differs between day and night and that mammals are diurnal potential predators of lizards.