Wildcat diet in the Cantabrian Mountains (Spain)

[Description of methods used for collection/generation of data] European wildcat scats were collected both systematically in fixed transects and opportunistically, between Dec 2018 and Feb 2020 in western Cantabrian Mountains and between Nov 2014 and April 2020 in Montaña Palentina Natural Park. For each sample we recorded the date and GPS location. Very old-looking scats were never collected. Scats were collected by experienced European wildcat researchers and assigned to European wildcats based on their morphology and smell. Although the certainty of assigning scats to carnivore species has been questioned (Monterroso et al., 2013), experimented researchers can accurately identify European wildcat scats. To assess the researchers’ success in scat identification, a subsample of 135 scats was genetically analysed (Ruiz-Villar et al. 2022). From 123 scats that we could genetically identify, 107 (87%) were from the Felis genus, 15 from Vulpes vulpes and one from Canis sp. The proportion of misidentified fox scats was the same in both study areas. Thus we were confident that Felis scats belong to wildcats considering that (1) wildcats and domestic cats segregate in the Cantabrian Mountains (Rodríguez et al., 2020), and we consequently avoided scat collection in areas used by domestic cats; and (2) no hybrids have been detected in the area so far (Tiesmeyer et al., 2020). To determine the prey species consumed by wildcats we used macroscopic identification of bones, teeth, scales, feathers and other identifiable prey remains extracted from washed scats. We determined the minimum number of individuals for each prey item in each scat based on the repetition of identifiable remains. We used the identification guide by Román (2019) to identify Spanish rodents from bone and teeth remains, and compared reptile and bird remains with specimens preserved in Doñana Biological Station. The study was undertaken with the correspondent permissions of the regional government of Castilla y León (EP/P/128/2019; AUTO/19/34, AUTO/2020/593) and Asturias (AUTO/2019/3267 for Asturias).