Development of non-target wildlife exclusion devices for small mammal trap protection

Authors: Roden-Reynolds, Patrick; Hummell, Grace; Machtinger, Erika; Li, Andrew

Submitted to: Wildlife Society Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2018
Publication Date: 9/3/2018
Citation: Roden-Reynolds, P.I., Hummell, G.F., Machtinger, E.T., Li, A.Y. 2018. Development of non-target wildlife exclusion devices for small mammal trap protection. Wildlife Society Bulletin. https://doi.org/10.1002/wsb.905.
DOI: https://doi.org/10.1002/wsb.905

Interpretive Summary: White-footed mice and other small rodents can carry the pathogen that causes Lyme disease in people. Once a tick bites an infected mouse, that tick may transmit the pathogen to a person. In order to study the ecology of white-footed mice, ticks, and the Lyme disease cycle, it is often necessary to trap white-footed mice and other small mammals. Typical traps are rectangular metal boxes that have a trigger and trap the animal alive. However, the bait used in these traps is often appealing to other animals as well, primarily raccoons and squirrels. This can be a problem when other mammals eat the bait that is meant to trap the small mammals. The goal of the study was to develop an device that would exclude these other animals from reaching the small mammal traps while still allowing small mammals to be captured. Two devices were developed and evaluated by reduction of disturbance, species that tended to disturb the traps, small mammal capture rates, and cost to build.

Technical Abstract: In wildlife studies, trapping small mammals is often required for life history studies, predator-prey interactions, or to assess for zoonotic disease. However, preventing disturbance from non-target wildlife such as raccoons (Procyon lotor) and Eastern gray squirrels (Sciurus carolinensis) is a significant challenge. The goal of the current study was to produce a protective exclusion device that would protect Sherman live traps from non-target wildlife interference while enabling low cost and efficient small mammal captures. two types of exclusion devices were created and compared, a modified Havahart® and a raccoon exclusion device (RED), for efficacy of reducing disturbance to Sherman box traps, and on the resulting small mammal capture rates. The modified Havahart® and REDs were similarly successful at reducing disturbance by raccoons. There was more disturbance by Eastern gray squirrels with the REDs, but small mammal capture rates in the REDs did not differ from the modified Havahart®, and each reduced non-target disturbance by approximately 50%. The modified Havahart® were over 5 times as expensive to produce than the REDs, and therefore the REDs offer a low cost and effective way to reduce non-target interference with small mammal trapping efforts.