Study site and species
The study was conducted at a highway bridge (126°57′26′′ E, 45°32′52′′ N) in Acheng district, Heilongjiang Province, northeast China. A large number of V. sinensis roost under the bridge. In summer, female V. sinensis roost and breed offspring here, forming a nursery (Wang., BY Shi, X Zhao, Feng., & Jiang., 2020). The population of bats arrives in the summer roost in the middle of June and leaves the summer roost by the end of September. We found thatFalco amurensis started to prey on V. sinensis during mid-August in 2018; this provided an opportunity to determine the effects of predation on activity rhythms ofV. sinensis .