Natural food availability
Small rodents are an important food source for red kites, especially during the breeding season (Andereggen 2020; Davis and Davis 1981). To quantify natural food availability, we therefore monitored the rodent activity in a total of 180 monthly transects representing the main agricultural habitat types in the region, evenly distributed across the study area (following Apolloni et al. 2018). We derived a monthly rodent activity index from traces in meadows as a proxy for the red kites’ natural food availability, as meadows represent the main vole-foraging habitat of red kites (for details on the rodent activity index, see Nägeli et al. 2022).