American black bears (Ursus americanus) are commonly captured throughout their range for research or management purposes. However, with the most commonly used capture devices, capture of non-target animals and disturbance of traps can substantially reduce capture efficiency. Here, we describe a passively-triggered snare designed to capture black bears and reduce such trap disturbance. The passively triggered snare system was designed to secure the snare to the foot of the bear as it attempts to access bait in the bottom of a hole by hooking a screen on top of the bait with its claws, pulling a PVC tube upward and gently tightening the snare to its wrist. We qualitatively compared this design (143 trap-nights) with 2 conventional methods, spring-activated snares (574 trap-nights) and culvert traps (129 trap-nights). Passively-triggered snares captured bears 15 of 74 times (20%) the traps were disturbed, spring-activated snares 22 of 360 times (6%), and culvert traps 25 of 63 times (40%). Both the passively-triggered snares and culvert traps prevented lost trap-nights to non-target species, such as raccoon (Procyon lotor). Passively-triggered snares prevented bear cubs from being captured, although several were observed attempting to take bait from the sets. Passively triggered snares, like culvert traps, require no concealment, but unlike culvert traps, are highly portable. The passively-triggered snare provides the same advantages as other snare designs, but has the potential to increase capture efficiency when disturbance by non-target animals is common. The results of our study suggest further evaluation of this technique is warranted. Comparisons with other techniques should be based on equal number of trap-nights and a study design that incorporates different environmental conditions.
- Volume 13
- Issue
- Pages 317-320
- Publication Date 1 January 2002
- DOI
- File Size 624.49 KB
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