Evaluation of Live-Capture Techniques for Free-Ranging Wolverines




Abstract: Wolverines (Gulo gulo) are a rare carnivore and live-capture efforts often comprise a significant component of field research projects. Wolverine studies have used aerial, snowmobile, hand-capture, and live-trap capture techniques. We reviewed existing wolverine live-capture data to evaluate sex-related biases associated with capture technique. We modified round log live traps, developed a new portable wooden live trap, and evaluated effects of live trap type, trap-site selection, and seasonal timing of trapping on wolverine capture success. Aerial capture techniques had a positive bias for capture of male wolverines. Live-capture rates were highest for portable wooden traps and lowest for barrel traps. Trapping success was highest during March when snow conditions were amenable to wolverine travel and temperatures improved bait effectiveness. Traps in corridor habitats were more successful than traps in noncorridor habitats. This difference was more pronounced in environments with rugged topography. We provide guidance for live-trap operation, describe animal handling procedures, and provide detailed instructions for construction of modified round log and portable wooden wolverine live traps. These will benefit future wolverine studies by increasing trap effectiveness and reducing risk of injury and mortality to captured wolverines.