Association of nesting Otus scops (Eurasian Scops Owls) with Xerotyphlops vermicularis (worm snakes) in Türkiye

We report the discovery of a novel relationship between Otus scops (Eurasian Scops Owl) and Xerotyphlops vermicularis (worm snake) found during systematic nest box inspections spanning 6 breeding seasons in central Türkiye. The presence of live X. vermicularis was specific only to nest boxes occupied by O. scops, which delivered snakes alive to the nest boxes. The snakes were found in 44% of 109 owl nests. While there was no significant difference in clutch or brood size between nests with and without snakes, hatchling success was significantly higher in nests with snakes (61% of hatched young fledged) compared to nests without snakes (29%). Insectivorous snakes were found both on, and within, the nesting material where they might remove commensal and kleptoparasitic insects (e.g., ants and fly larvae). Several research questions emerge from our findings, since non-consumptive interaction between blind snakes and owls is now known from different parts of the globe. Taken together, these studies suggest that behaviors potentially involving cognitive processes could, over evolutionary timescales, facilitate the emergence of mutualistic interactions through selective predation. Owl nests might be beneficial environments for the insectivorous X. vermicularis, but it remains to be determined whether owl–snake interactions are a facultative mutualistic relationship or only misdirected predation or even parasitism, primarily beneficial just for the owls.