Notes Functionality of a New Live-Capture Device for River Otters Andrew U. Rutter,* Alex T. Hanrahan, Clayton K. Nielsen, Eric M. Schauber A.U. Rutter, C.K. Nielsen Cooperative Wildlife Research Laboratory and Department of Forestry, Southern Illinois University Carbondale, 251 Life Science II, Carbondale, Illinois 62901 Present address of A.U. Rutter: 1899 W. Winchester Road, Libertyville, Illinois 60048 A.T. Hanrahan, E.M. Schauber Cooperative Wildlife Research Laboratory, Department of Zoology, and Center for Ecology, Southern Illinois University Carbondale, 251 Life Science II, Carbondale, Illinois 62901 Abstract Assessments of novel capture techniques are important to wildlife research. We used Comstock traps, a new live- capture technique, to capture North American river otters Lontra canadensis. We measured Comstock trap functionality in terms of river otter capture efficiency, furbearer capture efficiency, nonfurbearer capture efficiency, and malfunction rate. During 2014–2016, we captured 36 river otters (19 male, 17 female) in Comstock traps during 2,533 trap nights (1 capture/63 trap nights) at Crab Orchard National Wildlife Refuge in southern Illinois, USA. Eleven of 20 (55%) river otters assessed for capture-related injuries received an injury as a result of capture in a Comstock trap. The most common injury was claw loss (45%), followed by tooth fracture (25%) and lacerations (10%). The ease of setting Comstock traps and of releasing nontarget captures made them an appealing option for river otter live capture; however, two river otters died because of hypothermia, two died because of drowning, and one died because of traumatic injuries sustained during capture. Special care should be taken when selecting locations to set Comstock traps with regard to temperature and fluctuating water levels. Researchers attempting to live-capture river otters using this method would benefit by restricting their use to locations with predictable water levels and seasons with mild weather patterns. Keywords: capture efficiency; Comstock trap; Illinois; live-capture; Lontra canadesis; river otter Received: September 20, 2018; Accepted: November 12, 2019; Published Online Early: December 2019; Published: June 2020 Citation: Rutter AU, Hanrahan AT, Nielsen CK, Schauber EM. 2020. Functionality of a new live-capture device for river otters. Journal of Fish and Wildlife Management 11(1):238–244; e1944-687X. https://doi.org/10.3996/092018-JFWM- 083 Copyright: All material appearing in the Journal of Fish and Wildlife Management is in the public domain and may be reproduced or copied without permission unless specifically noted with the copyright symbol &. Citation of the source, as given above, is requested. The findings and conclusions in this article are those of the author(s) and do not necessarily represent the views of the U.S. Fish and Wildlife Service. * Corresponding author: rutter450@gmail.com Introduction Developing and adapting capture methods are important aspects of furbearer research (Kamler et al 2002; Kolbe et al. 2003; Koenen et al. 2005). Successful live-capture methods for furbearers are typically special- ized to target a focal species (Kamler et al. 2002; McNew et al. 2007) while treating both target and nontarget species humanely (Olsen et al. 1986; Sikes and Gannon 2011). Optimizing furbearer capture techniques to maximize capture efficiency while reducing capture- related injuries has directed much of the research on Journal of Fish and Wildlife Management | www.fwspubs.org June 2020 | Volume 11 | Issue 1 | 238 Downloaded from http://meridian.allenpress.com/jfwm/article-pdf/11/1/238/2511557/i1944-687x-11-1-238.pdf by guest on 11 September 2022