Apodemus at heights: Repeated records of Apodemus mice in tree canopies

Apodemus mice are predominantly terrestrial forest rodents but are also known to use arboreal habitats, with most systematic studies focusing on the lower vegetation strata, while direct observations of their movements in the forest canopy remain scarce. Using non-baited arboreal camera traps in managed forests of Lower Saxony, Germany, we recorded Apodemus mice on branches at three camera stations positioned 17.7, 18.4, and 21.3 m above ground. The highest observation occurred on a Douglas-fir ( Pseudotsuga menziesii ) on 8 August 2023. Additional detections were obtained repeatedly on two European beech ( Fagus sylvatica ) trees, with each camera recording mice on three separate nights. All observations occurred at night, between 22:39 and 01:57. We provide direct video documentation of Apodemus mice moving along natural branches at heights exceeding 20 m. The repeated detections indicate that canopy use by Apodemus mice is not necessarily restricted to exceptional climbing events. These records highlight the importance of considering vertical habitat use when studying forest rodents and demonstrate the value of arboreal camera traps for documenting poorly known behaviours of species usually monitored at ground level.