More info for the terms:
cover,
density,
hydroperiod,
shrub,
successionThe critical habitat feature for American mink is water. American mink prefer
streambanks, lakeshores, and marshes [
10]. Habitats associated with
small streams are preferred to habitats near large, broad rivers [
1].
American mink favor forested wetlands with abundant cover such as shrub thickets,
fallen trees, and rocks [
10]. In aspen (Populus spp.) parklands, male
American mink selected large, semipermanent and permanent wetlands with open
areas near shores, high water levels and irregular shorelines; these
characteristics are also associated with abundant avian prey [
3]. American mink
are common where abundant downfall and debris creates cover for
foraging. Logjams in streams create crayfish and fish habitat and
shelter for American mink [
1]. Peak American mink production in baldcypress (Taxodium
distichum) swamps occurred following extensive logging in the early part
of the twentieth century. Numbers have declined since then, probably
due to changed hydroperiod and decreased logging debris [
23]. In Quebec
the majority of American mink activity takes place less than 3 miles (4.8 km)
from water [
6]. In Michigan all American mink were observed within 100 feet
(30.4 m) of the water's edge [
25]. In Minnesota all den sites were
within 231 feet (69.9 m) of open water [
31]. In Idaho den sites were
16.5 to 330 feet (5-100 m) from water, and American mink were never observed more
than 660 feet (200 m) from water [
27]. In southeastern Alaska mink
spend the summers along streams and in upland muskegs; they spend the
winter in a narrow ocean beach zone [
26].
Wetlands with irregular, diverse shorelines are better American mink habitat than
those with straight, open, or exposed shorelines [
1]. Marshall [
25]
reported that 50 percent of American mink tracks in Michigan occurred in various
stages of hydrophytic succession, 37 percent in bushy and timbered
areas, and 13 percent in sedge (Carex spp.) and common cattail (Typhus
latifolia) type. In Alaska the highest American mink densities occurred in low
swampy terrain and in extensively interconnected waterways with abundant
fish [
8].
More American mink are trapped in wooded swamps than in marshes. The reported
abundance of American mink in baldcypress-tupelo (Nyssa spp.) swamps is at least
partially attributable to the abundance of food [
1].
In upland habitats, ecotones are most used; American mink avoid open areas and
prefer shrubby, dense thickets. Tall grass does not usually provide
adequate cover for American mink; however, sawgrass (Cladium jamaicense) marshes
in Louisiana support high American mink densities [
1].
American mink are adaptable in their use of habitat, particularly where prey are
readily available. They are tolerant of human activity. American mink inhabit
suboptimal habitats if prey is available, but are more mobile and change
home ranges more frequently in suboptimal than in optimal habitats [
1].
Home Range: American mink home ranges tend to approximate the shape of the body
of water the American mink uses most [
1]. However, in the prairie pothole
region, American mink tend to use an area rather than a linear shoreline [
2].
The use of the home range varies in intensity with respect to varying
prey availability. American mink tend to use a core area near a den site,
usually within 990 feet (300 m) of the shoreline. They move to another
den and core area several times a season; core areas tend to be places
of relatively high prey abundance. Usually only a small percentage of
the average or overall home range is used as the core area. In winter
fewer den sites are used, occupancy is of longer duration, and daily
travel distances are shorter than in summer [
1].
Male American mink have larger average home ranges than females [
1,
23]. Females
tend to use a greater proportion of their home range as a core area then
males do [
23]. Mitchell [
29] reported the average home range for male
American mink in Montana was 2 to 3 miles (3.2-4.8 km) in diameter. Vegetative
cover has a substantial impact on home range size in Montana: female
home ranges in heavily vegetated areas averaged 19 acres (7.7 ha),
whereas in sparse, heavily grazed areas they averaged 50 acres (20.1 ha)
[
29]. In Michigan male American mink average home range was less than 20 acres
(8 ha) [
25]. In Idaho males used 0.6 to 1.25 miles (1-2 km) of
shoreline [
27]. In British Columbia mink density on Vancouver Island
ranged from 1.5 to more than 3 American mink per kilometer of shoreline [
18].
Gerell [
15] reported that adult male American mink used an average of 8,679 feet
(2630 m) of shoreline, ranging from 5,940 to 16,500 feet (1800-5000 m).
Female adults used 3,300 to 9,240 feet (1000-2800 m), and juvenile males
used 3,465 to 4,620 feet (1050-1400 m).
In North Dakota prairie pothole regions, American mink home ranges were not
linear. Average home ranges were 1 to 1.5 square miles (2.59-3.8 sq km)
and typically included many individual wetlands [
1]. In Manitoba
prairie pothole areas, male home ranges had maximum lengths of 3.1 miles
(5.1 km) and maximum widths of 1.9 miles (3.1 km); prairie American mink tended
to have larger home ranges than other American mink populations [
2].
Home ranges of individuals rarely overlap, with the exception of the
breeding season when male home ranges overlap those of females [
1].