Arctic Shrew (Sorex arcticus)

County List:

Rule:

Forested or Mixed Forested/Nonforested Landscapes

1st alternative:
      (Any Lowland Conifer (Any Size Class))
      or (Mixed Lowland Conifer (Any Size Class))
      or Treed Bog
   adjacent to:
      (Sedge Meadow or Lowland Brush or Bog or Riparian)

2nd alternative:
      (Any Lowland Conifer (Any Size Class))
      or (Mixed Lowland Conifer (Any Size Class))
      or Treed Bog
   containing:
      Stand/Gap Openings

Habitat List:

view size class definitions

Literature:

This species occasionally lives in fairly dry fields and forest openings, but it prefers moist areas adjacent to a lake, bog, swamp, or ditch. Although it favors damp areas, a very high water table leads to a decline in Arctic shrews and an increase in the masked shrew population.

In the wild, an Arctic shrew feeds mostly on insects, such as sawfly larvae and adult grasshoppers.

Habitat Preferences: The arctic shrew seems to thrive best in the Upper Peninsula in spruce and tamarack swamps and in vegetation on lake and stream borders. Wilkinson (1980) found this soricid in the western part of the Upper Peninsula living chiefly in moist grassy areas bordering boreal woodland and swamps. Ozoga and Goertner (1963) reported the capture of a male in Iron County "…along the margin of an abandoned field, 12 feet from the edge of a cedar-spruce swamp, and about 15 feet from an intermittent spring-fed stream." Others have been taken in sedge openings in mixed conifer swamp in Alger County (Ozoga and Verme, 1968). In Minnesota, Whitaker and Pascal (1971) took specimens in dense grass along road ditches, in mixed grasses, strawberries, and ferns at forest openings, and in alder thickets. In Wisconsin, Clough (1960) caught arctic shrews in seasonally dry marsh containing grasses, sedge hammocks, forbs, clumps of cattail, and willow and red-osier shrubs. This evidence suggests that the arctic shrew may be found in many habitats in northern Michigan.

Associates: In the McCormick Experimental Forest in Marquette and Baraga counties, Haveman (1973) found the arctic shrew in mature hardwoods forests in close proximity to the masked shrew, pygmy shrew, short-tailed shrews, deer mouse, southern red-backed vole, meadow vole, southern bog lemming, and meadow jumping mouse. In bog environment, he found this same assemblage except for the deer mouse and southern red-backed vole. (The animals were caught in pit-fall traps). In three study areas in bog sites in Gogebic County, Wilkinson (1980) live-trapped 14 species of small mammals of which the arctic shrew was fourth most abundant. Of the total catch of 163 mammals (May 24 through August 10), meadow voles comprised 37%, masked shrews 23%, meadow jumping mice 12%, and arctic shrews 10%. Clough (1960, 1963) found similar relationships in the Wisconsin habitats he studied, adding only the house mouse as an associate. Jackson (1961) thought that masked shrews outnumbered arctic shrews about 25 to one in Wisconsin environments.

Food Habits: Little is known about the food eaten by the arctic shrew. Certainly larval, pupal, and adult insects and other invertebrates found in surface litter are consumed. Jackson (196) suggested that this species, owing to its attraction to stream and bog banks, might tend to prey on aquatic insects.