NON-INVASIVE SURVEY METHODS FOR DETECTING THE ENDANGERED BUENA VISTA LAKE SHREW (SOREX ORNATUS RELICTUS).
Erin N. Tennant; California Department of Fish and Wildlife; 1234 E. Shaw Ave, Fresno, CA, 93710; (661) 477-9239; erin.tennant@wildlife.ca.gov; Brian Cypher, Larry Saslaw, Tory Westall, Jacklyn Mohay, Erica Kelly, Christine Van Horn Job, Larry R. Saslaw
When surveying for any wildlife species, but particularly an endangered species, it is important to have non-invasive survey techniques available to prevent possible injury or death. For small mammals, like the Buena Vista Lake shrew (Sorex ornatus relictus: BVLS), live-trapping in Sherman-style box traps, or using pit fall traps, are common detection techniques. However, both methods have caused mortalities. In order to reduce impacts from live-trapping and possibly have better detection success, we investigated three potential non-invasive survey methods: track tubes, scat tubes, and camera traps. These three techniques were initially tested in areas with high detection rates of shrews during previous live-trapping surveys. We found that Reconyx camera traps specifically designed with a close focal distance outperformed all other survey methods. Track tubes were the least effective method. We followed up with a comparison test of scat tubes, camera traps, and small Sherman live-traps. We found that cameras outperformed live-traps (X2 = 42.24, 1 df, P < 0.0001) and scat tubes (X2 = 16.35, 1 df, P < 0.0001). Furthermore, of the 24 camera stations that detected shrews during the test, 21 detected them on the first night. Use of cameras is highly recommended for conducting surveys for BVLS.
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