Camera trapping for small mammals: the case of a non-native shrew
Abstract
Abstract In recent decades, motion sensor camera traps have revolutionised wildlife monitoring as a cost-effective strategy requiring less time investment than traditional monitoring methods. While medium-to-large body sized mammals are captured at sufficient resolution to permit confident species identifications, small mammal species (mice, voles, and shrews) are difficult to distinguish in conventional camera trap imagery. Since camera traps represent a potential solution for overcoming spatial and temporal constraints of traditional small mammal survey methodologies (live trapping), novel designs have materialised in recent years to adjust camera traps for observing smaller animals. In this research, we further refined an existing design, the Littlewood box, and investigated the optimal bait strategy to maximise small mammal detections in the Northeast of England within the currently known range of the non-native greater white toothed shrew, Crocidura russula . We found no significant difference in the probability of detection of small mammal species by bait type, but there were greater numbers of captures of shrew species at traps baited with mealworms. We conclude that the use of bait is associated with a greater number of captures for all small mammal species observed compared to non-baited traps. Despite the cameras being deployed in the centre of the known range of C. russula in Britain, this species was present at a lower proportion of sites than native small mammals.
Key Points
Objective
The study aims to refine camera trapping methods for detecting small mammals, particularly a non-native shrew.
Methods
- Refined an existing camera trap design (Littlewood box) for small mammals.
- Tested various bait types to maximize small mammal detections.
- Conducted the study in Northeast England focusing on the greater white toothed shrew.
Results
- No significant detection differences based on bait type for small mammal species.
- Increased captures of shrew species were noted at traps baited with mealworms.
- Non-baited traps captured fewer small mammals overall compared to baited traps.