Remotely triggered door and real-time monitoring for bear cage traps

We modified the bear cage trap with a low-cost remotely triggered trap door and fitted the trap with a motion activated camera that relayed bear captures to researchers in real time. We built 4 modified bear cage traps and used them to capture free-ranging American black bears (Ursus americanus) during summer 2020 on MPG Ranch in western Montana, USA. Lacking data on bear confinement time in traps from previous studies, we compared the amount of time that bears were confined in our modified traps with estimated confinement time had the same bears in our study been captured in traditional traps that were physically checked once daily at 0900, once daily at 1200, or twice daily at 0900 and 1600. We captured bears 30 times during 195 trap nights. The camera system relayed photos of all captures in real time and the remotely triggered door release was 100% successful. When we evaluated all bear captures and recaptures (n = 30), mean bear confinement time in our modified traps (4.92 hrs) was significantly lower than estimated mean confinement time had the same bears been captured in traditional traps that were checked once daily at 0900 (14.95 hrs), once daily at 1200 (10.73 hrs), or twice daily at 0900 and 1600 (7.01 hrs). For bears that were recaptured during regular trap monitoring hours (0700-1800) and remotely released without immobilization (n = 12), mean confinement time in our modified traps was <1 hr. By remotely monitoring traps, we saved an estimated US $6,580 or $13,624 in gas and staff hours during 3 months of trapping, had we physically checked traps once or twice daily, respectively. Our modified traps minimized animal confinement time, eliminated unnecessary animal immobilizations, and helped us maximize time and resource efficiencies. Our findings are relevant to bear research and management, and the technology we used can be adapted for trapping other wildlife species.