Development of nontarget wildlife exclusion devices for small mammal trap protection

Trapping small mammals is often required for life-history studies, evaluating predator–prey interactions, or assessing zoonotic disease. However, preventing disturbance from nontarget wildlife such as raccoons (Procyon lotor) and eastern gray squirrels (Sciurus carolinensis) is a significant challenge. Our goal was to produce a protective exclusion device that would protect Sherman live traps from nontarget wildlife interference while enabling low-cost and efficient small mammal captures. At the U.S. Department of Agriculture Research Center West in Beltsville, Maryland, USA, during 2017, we created and compared 2 types of exclusion devices—a modified Havahart® and a raccoon exclusion device (RED)—for efficacy of reducing disturbance to Sherman box traps, and on resulting small mammal capture rates. 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®; each trap protection type reduced nontarget disturbance by approximately 50%. The modified Havahart® device was >5 times more expensive to produce than the RED; therefore, the RED offers a low-cost and effective way to reduce nontarget interference with small mammal trapping efforts. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.