| Between 1997–1998, 28 (14M: 14F) northern river otters ( Lontra canadensis) were translocated to the Genesee River, western New York, to restore extirpated populations. River otters were radio-tracked for an average of 422 days (range = 152–602 days). Post-release dispersal distance of 22 (11M:11F) otters ranged from 1.2 to 54.0 km, with a mean of 12.5 km (95% CI = 8.5–23.7 km). The post-release dispersal distance of females was greater than that of males by a mean of 8.7 km (95% CI = 0.1–19.2 km). Male river otters exhibited greater home ranges than females during the breeding season. However, home range size did not differ between sexes outside the breeding season. Also, the number of male/female interactions increased during the breeding season. Distribution and movement patterns of male river otters during the breeding season appeared to be influenced by the distribution of females. The spatial organization of the reintroduced population was similar to the spatial organization of native river otter populations. Females exhibited intra-sexual territoriality, but did not appear to be territorial to males during any season. Males did not exhibit intra-sexual territoriality. River otters preferred backwaters and palustrine wetlands to recreational ponds and river and stream channels nonimpounded by beaver (Castor canadensis). The survival rate of translocated otters during the first year after the release was 0.89 (95% CI = 0.78–1.02). The annual survival rate did not differ between males (0.92, 95% CI = 0.79–1.08) and females (0.86, 95% CI = 0.70–1.06). Five (3M:2F) of the 28 translocated river otters were known to have died during the study period. Three (2M:1F) of the mortalities were caused by collisions with vehicles, and 2 (1M:1F) mortalities were from unknown causes. I was unable to document evidence of otters producing and rearing offspring during the study. Although no reproduction was documented during the radio-telemetry study, male-female interactions observed during the breeding season provide optimism for future reproductive success. At the conclusion of the radio-monitoring period, 21 (11M:10F) otters demonstrated evidence of establishing in the study area. Many of the habitats occupied by otters were isolated wetlands surrounded by a landscape dominated by human activities, such as agriculture and housing developments. Therefore, there is reason to be concerned that the fragmented landscape will reduce opportunities for interaction among otters, thereby reducing the likelihood of the establishment of a viable population. |
