Mink (Mustela vison)

County List:

Rule:

Forested or Nonforested Landscapes

      (Lake or Pond or River)
   adjacent to:
      (Marsh 1 or Marsh 2 or Lowland Brush)
   containing:
      Dead Down Woody Debris

Habitat List:

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Literature:

Mink frequent streams, ponds, and lakes with at least some brushy or rocky cover nearby.

In the summer the diet consists of crayfish supplemented mostly with frogs and small mammals, including shrews, rabbits, jumping mice, and muskrats. The mink also consistently eats fish, such as minnows and sunfish, as well as a variety of ducks and other fowl. In winter, mammals, especially muskrats, are the primary food source.

Habitat: Streambanks, lakeshores, and marshes. Favors forested wetlands with abundant cover such as thickets, rocks, or windfalls.

Special Habitat Requirements: Den sites inside hollow logs, natural cavities under tree roots or in burrows along stream, marsh, or lake edges.

Habitat Preferences: Michigan is a favored residence for an animal like the mink which is equally at home on land and in streams, rivers, lakes, ponds, and marshes. Although most accounts of the favored environments of Michigan mink place the animal in or along the edge of water, this lively, ubiquitous mustelid can be expected some distance from water, even using a backyard woodpile as shelter on occasion. Wood, for example, tracked one mink through the snow on a circular course cross country in Washtenaw County. He also found other individuals on hunting forays as much as ½ mile from water. The only habitat not used on a regular basis is probably heavy upland woods. When away from aquatic areas, the mink seems most at home in second-growth cover of mixed shrubs, weeds and grasses, and the edges of cultivated fields and pastureland.

Density and Movements: Mink populations may be highest in large marshes which contain cattails and muskrat beds, such as those at the Seney National Wildlife Refuge in Schoolcraft County.

Behavior: Mink generally den near water. The animal may excavate its own ground burrow under the protection of tree roots, beneath felled logs, in rock ledges, logjams, drain tiles, brush piles, and stream banks; and even under buildings in rural settings. Mink also take over marsh houses of beaver or muskrat and more frequently the excavated burrows of the muskrat, woodchuck, or ground squirrel.

Key Components of Habitat: Permanent surface water, vegetative cover within and adjacent to wetland; structural cover (e.g. logjams, downfall, boulders) to provide cover and foraging sites; den sites.

Management Actions to Enhance or Maintain Habitat Quality: Maintain vegetative cover within and adjacent to wetlands; maintain or increase structural/physical diversity associated with wetland ecotones (e.g. downfalls, logjams, backwaters); increase pool:riffle ratio; increase water permanence.

Habitat: Mink occupy a variety of wetland habitats, including streams, rivers, lakes, freshwater and saltwater marshes, and coastlines. Linscombe et al. evaluated fur harvest records and determined that all states and provinces with the highest mink harvests were those with abundant wetland habitat. Indeed, Allen suggested that permanence of water was the most important variable for evaluating the suitability of small palustrine (marshes <1000 acres) and riverine habitats for mink; shorelines and emergent vegetation were also important correlates of mink activity. Racey and Euler noted a decrease in mink activity accompanying shoreline development by cottage owners in central Ontario; lot-clearing activities included removal of trees, shrubs, and emergent and submergent aquatic vegetation. Mason and MacDonald found a strong correlation between mink sign (scat and footprints) and the density of mature willow trees, saplings, and shrubs.

Although mink in Sweden occupy water courses, marshes, lakes, and sea coasts, they are most abundant near eutrophic lakes. On a river system in Texas, mink used small streams only when the river was flooded; otherwise they were restricted to the floodplain. Mink in Scotland are usually found near larger rivers and lakes, but they avoid small streams with treeless banks. In contrast, Davis reported that mink in Texas preferred small streams to large broad rivers.

In Michigan, Marshall found 58 of 66 sets of mink tracks in snow in "hydrophytic successions." Of the 58, there were 43 (74%) in bushy or timbered vegetation types and 15 (26%) in sedge or cattail types. He located all tracks within 100 ft of water.

In the Everglades, mink and river otters followed changes in distribution of aquatic habitat. They used marshes during the wet season but moved within the swamp to central ponds late in the dry season.

Arnold studied habitat selection by male mink in the prairie pothole region of southwestern Manitoba. He reported that mink selected large, semi-permanent, and permanent wetlands with high water-levels, wide zones of emergent vegetation, and irregular shorelines, characteristics that were also associated with abundant waterfowl prey.

The key to habitat that is intensively used by mink appears to be a dependable source of food. In coastal habitats, mink forage primarily in the intertidal zone; foraging areas are smaller where food supply is the greatest. Linn and Birks found that core areas included some distinctive feature, such as a den site or an abundant food supply. Burgess and Bider found an increase in mink use in a section of stream that had been improved for brook trout. They attributed this increase to the greater biomass of crayfish that had resulted from modifications to the stream. Nichols and Chabreck reported more mink in swamps as opposed to marshes in Louisiana and associated the higher density with a greater abundance of preferred food. Melquist et al. assessed mink use of logjams, streambanks (shoreline to high-water mark), and riparian upland vegetation in Idaho during autumn. Use of riparian habitat was dominant in September but decreased from October to December, when logjams became more important. This shift was attributed to food supply and a lack of access to upland areas as a result of deep snow cover in December. Streambanks received relatively constant use (about 20% of locations).

Although mink may use cavities in roots of trees, rock or brush piles, logjams, and beaver lodges, the most widely used den sites are bank burrows of other animals, particularly muskrats. Usually the burrows have been abandoned before the mink occupy them, although mink may coexist in large burrow systems with muskrats.

Eberhardt and Sargeant found that the availability of dens along marshes in North Dakota was related to the suitability of marshes and the extent of shoreline grazing by cattle. Errington suggested that muskrat activity was necessary to keep dens in a state of repair that maintained their attractiveness to mink. This activity would be particularly important on grazed shorelines because the cattle may collapse the burrow systems. However, on ungrazed shorelines, only infrequent use by muskrats would be necessary to keep dens suitable for mink.