Influence of body mass, sociality, and movement behavior on improved detection probabilities when using a second camera trap

Abstract Maximizing detection probability is a common goal for occupancy studies using camera traps for data collection. Placing additional cameras at a survey station may improve precision of occupancy and detection estimates. However, these benefits are situational and potentially influenced by species' physical characteristics and behavior. We estimated null occupancy and detection probabilities for 20 mammalian species with >10 detections at multiple sites from one- and two-camera data sets from 63 stations set in a commercial forest reserve in Sabah, Malaysian Borneo during October–December 2015. We used a cross-validated absolute shrinkage and selection operator approach to model the effects of species’ body mass, social behavior, dietary niche, and foot posture on detection probability using one- and two-camera designs. The number of species detections, sites where species were detected, detection probability estimates, and precision of model parameter estimates for all species improved using two cameras. Our results showed that unguligrade species were associated with both high detection probability estimates with one camera and also the greatest improvements using the two-camera design in detection probability compared to all other species. Greater improvements in precision of model parameter estimates from two-camera designs were observed in species detected less frequently. Our data suggests that camera designs need to be adapted based on the focal species and we suggest that future occupancy studies collect preliminary information to maximize effectiveness of camera effort and ensure that data collection is efficient and meets project needs.