Efficiency of pitfalls versus live traps in enumeration of populations of Microtus pennsylvanicus

Publisher Website
Google Scholar
Abstract
Two populations of Microtus pennsylvanicus were trapped simultaneously with Longworth live traps and pitfall traps over a 3- and a 4-year period. The number of voles enumerated by live traps was usually between 2 and 4 times that enumerated by pitfalls. Of the 3671 new voles caught, 53.7% were first caught in live traps. Pitfalls captured more of the juveniles first (56%) and live traps captured more of the adults first (76%). Animals entering live traps for the first time were about 4 g heavier than those entering pitfalls for the first time. The time lag between entry first into pitfalls and then to live traps was 4–6 weeks; the time lag between entry first in live traps and then to pitfalls was 2–7 weeks. Approximately 18% of all voles never entered live traps. Live traps captured about 83% (N = 747) of all dispersers whereas pitfalls captured about 46%. We conclude that live traps were much more effective than pitfalls in capturing this species. These results are very different from those reported from studies on Microtus townsendii.