Sometimes we have unexpected visitors to our mountain dooryard. Last December 6, shortly after lunch, my husband, Bruce, stepped outside on our veranda. That was when a mink bounded past almost at his feet and down into the lilac shrubs next to the house.
“I think I just saw a mink,” Bruce shouted to me as he ran upstairs to get his camera.
I grabbed my binoculars, and then both of us stepped quietly on to the front porch, which overlooks our unkempt yard and 100-year-old lilac shrubs.
Guided by scolding black-capped chickadees, we spotted the mink in the understory beneath the lilac bush on the left side of the porch. The chickadees flew above the creature, continually scolding as the mink hurried past the porch and down to the springhouse where it disappeared among the broken remains of cattails we had planted in the small wetland around the springhouse years ago.
Ever since one of our hunter friends, Tim Tyler, had reported seeing a mink beside our stream, I had wanted to see one for myself. But our first order, wooded stream didn’t seem likely habitat for a fish-loving mammal like a mink. Of course, our stream does have crayfish, another mink favorite, and our forest contains plenty of mice, squirrels, shrews, frogs, insects, snakes, and turtles, which mink also eat. And since the last feral cat disappeared, courtesy probably of a fisher, we have numerous cottontail rabbits living in our yard and First Field. They, it turns out, are also favorite mink prey especially in the winter when they depend on mammals for their sustenance.
We assumed that our mink was the same one our son Dave saw from our guesthouse front porch back on October 11. That morning he wrote on his daily Twitter account, which he calls The Morning Porch, “A large, dark weasel flushes a rabbit from cover, rearing up on its hind legs: mink! We stare at each other with mutual disbelief.”
Apparently, young mink disperse in early autumn so we wondered if our visitor was a youngster looking for its own territory. After all, most juveniles move less than three miles from their birthplace and the Little Juniata River, ideal habitat for a mink, is only a mile-and-a-half from our home. Furthermore, because a female mink needs a range of 20-50 acres or 5,900 feet along a stream while the larger male claims 8,500 stream feet, our stream could probably sustain a single mink of either sex. The mink we saw seemed large enough to be a male and naïve enough to be a juvenile. As usual, though, with the wild animals we encounter here, we could only guess at their intentions.
Yet despite having what seems to be unlikely habitat for mink, they do sometimes like to den in ground cavities beneath downed trees, which are strewn along our stream. Especially in winter mink use forests such as ours for prey and may occupy deserted rabbit or woodchuck burrows. Although they do remain in their dens and sleep for several days during bad winter storms and extreme cold, they also need to eat. Thus, even though they are most active in evenings, night time, or early mornings, if they are hungry enough they may be out in midday too as our mink was.
The word “mink” comes from the Swedish “maenk,” and the American mink has been known in scientific circles as Mustela (Latin for “weasel”) vison (Swedish for “kind of a weasel”) since 1777. But in 2005 cytogenetic and biochemical data put the American mink in the same genus as the extinct sea mink Neovison macrodon. The sea mink was larger than the American mink and ranged from coastal Massachusetts to Newfoundland. It was extirpated in the 19th century, some say as early as 1860, by trapping, although there were a few possible later sightings. Our American mink remains in the Family Mustelidae, but its scientific name is now Neovison vison. In addition to American mink, other common names are vison, common mink, woods mink, water weasel, and least otter.
Like otters, mink sometimes play and slide down muddy or snowy banks. They swim and dive in water, aided by stiff hairs between the toes of their hind feet, and they can dive as deep as 18 feet and swim underwater for 300 feet. Their lovely dark chocolate brown fur, patched with white on their chins, throats, chests, and bellies, has oily guard hairs that make their fur water-resistant. Their long, tubular-shaped bodies help to reduce drag in the water and enable them to chase muskrats underwater and into their burrows where they kill and eat them. In addition, they prey on waterfowl and their eggs. One study in Manitoba, Canada, in 1989, estimated that a single American mink ate three to seven adult ducks, 15 to 25 one-week-old ducklings, and 18 to 30 duck eggs during a single breeding season.
They, in turn, may be killed by great-horned owls, hawks, coyotes, red foxes, bobcats, otters, lynx, and alligators, the latter two reflecting their wide range from Canada through most of the United States except portions of the dry southwest and California.
Because of their luxuriant fur, they were long ago introduced to Russia and other European countries either deliberately or as escapees from fur farms. Now they are considered an invasive species, linked to the decline of water voles in the United Kingdom and the decline of waterfowl throughout Europe. They also kill the smaller European mink. For all these reasons, they are hunted as vermin by wildlife managers.
American mink have excellent vision, sense of smell, and hearing and can even hear the ultrasonic cries of their rodent prey. They use secretions from their anal glands to mark their home range boundaries. When they are threatened, in addition to snarling and fighting, they may empty their glands and release a scent described by one early naturalist as worse than skunks.
Sometime in February or March, the males use their anal gland scent to attract females. In addition, both sexes emit chuckling sounds that are thought to increase sexual stimulation. The males fight during mating season which lasts three weeks and a single mating can last from 10 minutes to four hours. The females are receptive on seven-to-10-day intervals, and both sexes may have more than one partner. The females have delayed implantation of the embryos which allows pregnant minks to keep track of environmental conditions and select an ideal time and place for the development of their embryos. That is why they may have young anywhere from 40 to 75 days after mating even though the actual embryonic development is 30 to 32 days long.
The young are born in nesting chambers one foot in diameter that are part of their mother’s larger underground dens. Their average litter size is four but can range from two to eight because older females have more young. Usually, young mink are born sometime in May in Pennsylvania. Blind and hairless at birth, by two weeks they have reddish-gray hair over their bodies and at three weeks their eyes open. They grow quickly and are weaned when they are five weeks of age. Their mothers then bring them food at the den, but they are hunting with her at seven to eight weeks old.
American mink are considered to be bio-indicators of pollution in their aquatic environments because of their sensitivity to mercury and polychlorinated biphenyls (PCBs). If the levels are high enough, they lose weight, have tremors and convulsions, and ultimately die.
Although mink can live at least eight years in captivity, three years is the average life span of wild mink. We haven’t seen any mink since our sighting a year ago, but because they are usually secretive in nature, we hope that “our” mink is still making a living along our Plummer’s Hollow stream.