A Direct Comparison of Enclosed Track Plates and Remote Cameras in Detecting Fishers, <em>Martes pennanti</em>, in North Dakota

Abstract

Fishers (Martes pennanti) historically were reported to occupy forested areas of northeastern North Dakota, but the population was presumed extirpated during the 1900s as a result of overtrapping. Recently (≤15 years), Fishers have been recolonizing the state, and there is increasing interest in developing approaches for monitoring the population. During the period June–August 2008, we compared the efficacy of remote cameras and enclosed track plates in detecting Fishers in riparian forest along portions of the drainage basin of the Red River of the North in eastern North Dakota. We monitored 122 scent stations, each composed of both detection devices, with the remote camera positioned to monitor the entrance of the enclosed track plate. Fishers were detected at 40 of the 122 scent stations (32.8%) distributed along approximately 790 km of riparian forest. Among those 40 stations, Fishers were detected by both camera and track plate at 28 stations (70.0%), by camera only at 9 stations (22.5%), and on track plates only at 3 stations (7.5%). Overall, Fishers were detected 37 times by camera (92.5%) and 31 times on a track plate (77.5%). From photographic evidence at the 37 stations where Fishers were detected by camera, we determined that the average latency to initial detection was 4.8 days (SE 0.3, range 1–8). Among the 37 stations where Fishers were detected by camera, detections most frequently occurred on one (27 sites) (73.0%) or two days (7 sites) (19.0%) of a detection period.