Summer Home Range Size and Habitat Use by River Otters in Ohio

Reintroduced river otters (Lontra canadensis) are an important component of Ohio’s biological diversity, and are a key indicator of wetland and watershed health and quality. However, few data are available on their home range sizes and habitat use. We monitored river otters using radio-telemetry in the Killbuck Watershed, in northeastern Ohio, during 2002 and 2003 to determine home range and habitat use. Overall, mean home range size was 802.4 ha (range = 84.5–3,376.3, SE = 448.2) for female river otters and 1,101.7 ha (range = 713.8–1,502.6, SE = 102.2) for male river otters. Home range size of female and male river otters did not differ in 2002 (P = 0.763), but males had larger home range size than females during 2003 (P = 0.001). Based on compositional analysis, habitat use differed in proportion to availability of the 5 habitat types available in the study area (marsh, wet meadow, riparian/floodplain, open water, and flooded upland) (P < 0.0001). Overall, river otters used marsh habitat with a diverse association of floating aquatics and emergent vegetation in greater proportion than was available. Knowledge and understanding of river otter habitat use and home range size in Ohio will help managers identify habitats suitable for river otters in the Midwestern United States.