Species: Sorex palustris

There are almost no data on home range size. Home range was 0.2-0.3 ha for two live-trapped Manitoba individuals (Buckner 1966, Buckner and Ray 1968). Churchfield (1990) reported that "aquatic species such as NEOMYS FODIENS and SOREX PALUSTRIS also have linear home ranges based on the banks of streams and rivers. They occupy a length of riverbank plus the adjacent area of water and, often, a small area of hinterland. N. FODIENS typically has a home range length of 20-93 m (65-305 ft.) alongside a stream." After 14 months of observing S. PALUSTRIS in captivity under near-natural conditions, Sorenson (1962) concluded that "a dominance hierarchy and territoriality did not exist." He noted that even nests were not defended. <br><br>Information on population density likelwise is scant. In Michigan, seven individuals were found along a 200-ft section of stream in one night with 30 Sherman traps (Master 1978). Population densities in the Appalachians appear to be quite low, though numbers are not available (Pagels 1990, 1991). In Canada, Banfield (1974) reported that this shrew is usually uncommon but sizeable populations sometimes occur in favorable locations. Generally numbers are highest in summer when young are born and drop off sharply in autumn, with very little decrease through winter. Population densities for shrews in general depend on species, season, habitat, and probably prey density (Churchfield 1990). <br><br>Common predators include fishes such as trout, bass, and pickerel, minks, otters, weasels, snakes, and, occasionally, hawks and owls (Merritt 1987, Godin 1977). Internal and external parasites commonly include nematodes, tapeworms, fleas, ticks, and mites (Conaway 1952, Webster 1987, Whitaker and Schmeltz 1973), but there is no evidence that they cause significant harm (Churchfield 1990).