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.

Stream community richness predicts apex predator occupancy dynamics in riparian systems

“…North American, European Lutra lutra) primarily forage based on prey availability (Erlinge 1968, Anderson and Woolf 1987, Lanszki and Körmendi 1996, and mink are most active in areas where prey abundance and availability are high (Burgess and Bider 1980, Wise et al 1981, Larivière 2003, Wolff et al 2015. River otter primarily prey on fish (Roberts et al 2008, Barding and Lacki 2012, Feltrop et al 2016), but also consume crustaceans and molluscs (Satterthwaite-Phillips et al 2014, Fretueg et al 2015, Feltrop et al 2016). Diets of mink and river otter overlap, however, mink are a generalist carnivore taking more terrestrial prey than river otter (Wise et al 1981).…”

“…Therefore, we did not find support for the prediction that river otter presence is driven by prey availability. River otter primarily eat fish and crayfish based on availability (Roberts et al 2008, Stearns and Serfass 2011, Fretueg et al 2015, but data for crayfish abundance and biomass were not available for our study sites and thus not used in this analysis. We did not use any interactions or quadratic terms in our analysis.…”

A molecular approach to study Hymenoptera diets using wasp nests

“…Recent developments in molecular techniques mean that even low-quantity and low-quality DNA samples can be analysed efficiently and applying these techniques to the analysis of faecal samples for assessing diet represents an interesting opportunity (Monterroso et al 2019;Waterhouse et al 2014). This could be a particularly useful strategy for assessing seasonal variation in the diets of taxa who deposit their faeces in permanent sites such as latrines or other territory marking sites (Fretueg et al 2015). Such approach could provide valuable insight into the diet of nest-building Hymenoptera where larval faeces accumulate within the nest.…”

Impacts of Pollutants on Beavers and Otters with Implications for Ecosystem Ramifications

“…While otters consume a large number of species, they feed mostly on fish and shellfish (90% of their diet), and less so on other invertebrates, amphibians, birds, and mammals (Anderson‐Bledsoe and Scanlon ; Carss ; Cote et al ; Evans et al ; Fretueg et al ; Kean et al ; Mason et al ; Reid et al ). This is of prominent conservation concern because the position of river otters at the top of the food chain increases their susceptibility to bioaccumulation of a wide‐range of contaminants (Anderson‐Bledsoe and Scanlon ; Evans et al ; Kean et al ; Mason et al ).…”