A proof of concept for linking individual identity to camera traps

Small mammal movements are difficult to monitor, both visually and with remote tracking devices, due to the animals' small body size and elusive behavior. Cameras deployed at fixed locations can provide continuous, non‐invasive records in natural habitats, yet camera‐derived indices remain sparsely validated and generally do not allow inference at the individual level. In contrast, capture–recapture regimes can provide abundance estimates and individual‐level measures, e.g. marking the individual animals with passive integrated transponder (PIT)‐tags. By combining camera traps with a fixed RFID (radio frequency identification) reader, more information can be extracted than when the methods are used separately. Bank voles Clethrionomys glareolus , with implanted PIT tags, were successfully identified at the individual level using the RFID‐integrated camera trap; however, some visits were recorded by only one method. These mismatches were most consistent with entrance‐level behaviour and camera‐trigger settings, including partial entries, reversals, and repeated movements during the camera's quiet period. Co‐locating a fixed RFID reader with a camera trap provides a way to reconstruct individual encounter histories while simultaneously recording the broader animal community. The system links PIT‐tag identity to camera detections and makes it possible to describe detection mismatches at the individual level. Used together, the two systems can improve interpretation and quality of camera‐based monitoring data of small mammals.