“…Competition between pine marten Martes martes and stone marten Martes foina , two closely related, very similar European carnivores, has been widely studied through radio‐tracking (Wereszczuk & Zalewski, 2015), molecular analyses (Monterroso et al, 2016; Posluszny et al, 2007; Rosellini et al, 2008), snow‐tracking (Goszczyński et al, 2007) and camera trapping (e.g., Balestrieri et al, 2019; Gazzola & Balestrieri, 2020; Monterroso et al, 2016; Rosellini et al, 2008; Torretta et al, 2017). When these martens live in sympatry with several other carnivore species (e.g., the red fox Vulpes vulpes and the European badger Meles meles ), stone martens are mostly nocturnal, whereas pine martens show a cathemeral or diurnal pattern (Fonda et al, 2017; Monterroso et al, 2014; Mori & Menchetti, 2019; Torretta et al, 2017). Zalewski (2001) showed that, in Central Europe (Białowieża Primeval Forest), the activity rhythms of the pine marten change seasonally, with daytime bouts increasing when cubs are present and with strictly nocturnal habits in winter.…”