Summer Diet Characteristics of North American River Otters (Lontra canadensis) in Central Illinois

Abstract

North American river otters (Lontra canadensis) frequently visit latrines where they deposit urine, feces, and anal secretions as olfactory signals. River otter scat was collected from latrines to identify prey at the Emiquon Preserve and the Emiquon National Wildlife Refuge located along the Illinois River near Havana and Lewistown in Fulton County, Illinois. Remains of prey from dissected scats were compared to osteological resources to taxonomically identify the remains. Fish were present in 85.4% of the dissected samples. Common carp (Cyprinus carpio) were the most common fish preyed upon during the study, occurring in 69.8% of all dissected samples. Crayfish were present in 77.1% of samples. Amphibians, insects, filamentous algae, green-winged teal (Anas crecca) or blue-winged teal (A. discors), and muskrat (Ondatra zibethicus) were also consumed. The minimum number of individuals (MNI) consumed was also determined based on the prey remains present. The results of a two-tailed Fisher's exact test demonstrated there were significant differences in the percentage of prey consumed by otters at Emiquon and in previous studies conducted in Whiteside County, Illinois, and Alberta, Canada.