Birds employ various methods to defend their nests against predators, such as nest defense behavior. The males of the Eurasian Wren (Troglodytes troglodytes) are polygamous and build multiple dome-shaped nests. Although previous studies report a moderately high predation rate for Eurasian Wren nests, its predator assemblage is poorly understood. To investigate the Eurasian Wren’s potential nest predators through the breeding cycle, we conducted direct observations and surveillance using trail cameras on Shikoku Island, Japan. Our recordings revealed several predators and potential threats to wren nests, including Eurasian Jays (Garrulus glandarius), a crow (Corvus sp.), and a Japanese weasel (Mustela itatsi), which were found to attack the nests at different reproductive stages. Notably, we observed a nest-constructing male wren encounter a Japanese striped snake (Elaphe quadrivirgata) and interact with it in an intriguing way. Instead of attacking the snake or sounding an alarm, the wren flew out of the nest and repeatedly approached the snake before backing away to maintain a cautious distance from the nest. This behavior consequently led the snake away from the nest, with the wren accompanying the snake to alter its path effectively. This “lead-away” behavior may thus be a distraction display. Our finding underscores the possibility of proactive nest defense behavior occurring even before mating. It is essential to explore how birds behave to ensure the safety of nesting sites at the early stage of the nesting cycle. Received 25 October 2023. Accepted 12 August 2024.

2023
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