Surprise Visitor

American mink by Chuck Homler

American mink (photo by Chuck Homler, Creative Commons Attribution-ShareAlike)

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.

Mink chasing frogs in a lawn

Mink chasing frogs (Eric Bégin, CC Attribution-Noncommercial-NoDerivs)

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.

mink with garter snake

American mink with garter snake (Eric Bégin, CC Attribution-Noncommericial-NoDerivs)

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 at the British Wildlife Centre

American mink at the British Wildlife Centre (Marie Hale, CC Attribution-only)

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.

Visitors from the River

Occasionally we are reminded that the Little Juniata River flows past the northeast end of our mountain when unexpected visitors from the river appear here.

Imagine, for instance, my husband Bruce’s surprise when driving down our narrow, gravel, wooded, hollow road one spring morning and encountering a large snapping turtle plodding up toward him. This happened twice in the almost 30 years he commuted to State College. One turtle was only a quarter of a mile from the river, but the other had made it over a mile. In both cases, Bruce stopped the car and waited patiently for it to get out of the way.

Each time I was green with envy and rushed down to look for the creature. I was hopeful that the turtle was a female and looking for a place to lay her eggs. After all, the American or common snapping turtle Chelydra serpentina serpentina has been known to live in small streams like ours and to bury a clutchful of 11 to 83 white eggs in the mud of streambanks. But both times we never saw another sign of a snapping turtle. Whatever they had been doing on our road, they obviously had turned around at some point and headed back to more suitable habitat in the river.

Water birds have also made unexpected visits here. Last April Bruce saw a belted kingfisher sitting on a tree branch at the edge of First Field, at least a mile and a half from the river. Since April is a migration month for kingfishers, it may have been resting before moving down to the river where belted kingfishers have nested for years in the riverbank. As we cross the one lane, steel bridge over the river, we often see them flying back and forth and hear their loud, rattling calls. Sometimes one even perches on the wooden bridge railing.

A more frequent avian visitor has been the great blue heron. Still, I was startled to flush one from the edge of the Far Field one morning. According to Robert W. Butler, who has written the definitive account of this species for THE BIRDS OF NORTH AMERICA, although great blue herons are primarily fish eaters, they will stalk over upland fields in search of voles and other rodents. Yearlings, which often have a hard time catching fish, are most likely to hunt for small mammals in fields. So, perhaps, that great blue heron I saw, and the others that occasionally fly over our First Field, are not out of place at all, but merely searching for food.

Probably the most amazing avian river visitor appeared here on October 4, 1989. It was one of autumn’s glorious days–breezy, cloudless, and crisply cool. As I descended First Field through the locust grove, I heard a high-pitched cree-cree-cree. It could only have been an osprey. I stopped and scanned the sky with my binocular. Finally, I spotted it circling above me, a fish clasped tightly in its talons.

It made several passes over the field and then flew to a tree branch on Sapsucker Ridge where it stood and looked around silently. Moving slowly, I sat down in the locust grove and watched it through my binocular. The top of its white head glowed in the sunlight, while its broad, dark, eye and cheek stripe flowed down the back of its neck like a cowl. It sat motionless, ignoring the fish in its talons, and only looked alertly around when a nearby pileated woodpecker called.

After half an hour, I slowly stood up and started moving toward the osprey, hoping for a closer view. This aroused it from its reverie, and it started calling again as if warning me off. Then it leaned forward, displaying snowy white underparts, before taking flight, still grasping the brown fish it had probably caught in the river. No doubt it had been migrating since the migration period for ospreys in Pennsylvania extends from the second or third week in August to the fourth week in October.

Our mammal visitors from the river have been even more surprising because our Plummer’s Hollow stream, which originates from springs in First Field, is never much more than five feet wide as it flows the mile and a half down to the river. Because, in summer and fall, it is often barely a trickle, it does not support fish although it does have a good population of crayfish and provides a damp environment for salamanders.

So what was a mink doing halfway up the hollow, poking its nose in woody debris spanning the stream one April day in 1997? Mink, after all, prefer to eat muskrats, although they will settle for small mammals such as voles, mice, shrews, cottontails, and even squirrels, all of which live in our hollow. And crayfish are a favorite summer food, followed by muskrats, frogs, fish, snakes, small mammals, and waterfowl.

Again, I was not lucky enough to see the mink, but Tim, one of our hunters, was taking a noonday walk, and had an excellent view of the creature. Perhaps it was a female in search of a den site since mink will sometimes construct dens along the banks of streams or under stumps and logs, and they commonly give birth in April or May. But they usually take over abandoned muskrat houses, and, so far, we have not seen muskrats up here.

Early last May another hunter friend, Jeff, drove up to show us the body of a nursing mink he had found by the side of the highway next to the river. As we admired her almost untouched, silky, chocolate brown coat, we could see why mink fur is so popular. Her death by car meant that her litter of from four to nine probably perished, although both parents do rear the young and bring food to the den. But weaning the kits does not begin until they are five to six weeks old. Since wild mink usually live three to six years, we wondered if the dead female was the same mink Tim had seen three springs ago? As usual, nature presented us with more questions than answers.

Then, last February 27, we had our strangest visitor yet from the river. It was 42 degrees and overcast at dawn. Misty rain had been falling off and on for days and most of the snow had melted. Every spring on the mountain spouted water into our stream. Lying in bed, I could hear water rushing down the drainage ditches. Another dull day, I thought, as I listened to one of three wintering song sparrows singing.

But, as I went into the kitchen, the intercom buzzer from our guesthouse went off. Our eldest son, Steve, who was visiting for the weekend, yelled, “Mom, come quick! There’s a beaver in the stream below the guesthouse.”

At first I didn’t believe him. But as he insisted, I grabbed my binocular, pulled on my boots and jacket, and ran down in time to see an adult beaver emerge from the culvert pipe beneath the road. I was amazed at how large it was especially when it stood up on its hind legs beside the drainage ditch to look around. We had plenty of time to study its paddle-shaped tail lying flat on the lawn and admire its sleek, dark brown coat.

Although our sons Dave and Steve stood with me on the guesthouse porch less than 50 feet from the beaver, quietly talking, it seemed supremely unconcerned by us. Perhaps it was looking over the terrain and trying to decide if it had potential as a future home. But two houses and three adult humans were probably enough to discourage it. After five minutes of indecision, it continued up the drainage ditch toward the powerline right-of-way, wading through the six inches of flowing water.

I rushed back to our house to rouse Bruce who grabbed his camera and tripod. Together we ran up our driveway to the powerline right-of-way ahead of the beaver. While I stood on one side, scanning downstream with my binocular, Bruce crossed the ditch and set up his camera and tripod on the embankment above.

When the beaver came into view, I called quietly to Bruce, “Here it comes.”

Remaining still and out of sight, I watched while the beaver attempted to climb over a fallen tree and then toppled over backward. Undeterred by that setback, it tried again and made it over what must have been the last of dozens of fallen trees that span the stream.

It waddled determinedly up the ditch, by then only intermittently filled with meltwater. Finally, it sensed Bruce above it and stopped. Again it sat up on its hind legs and peered toward Bruce, who shot picture after picture before the beaver slowly turned around and headed downstream.

Again we watched from the guesthouse porch as it went down into the culvert pipe and emerged in the stream directly below us. Hopeful that it might set up housekeeping in our marshy meadow, I didn’t follow it down the mountain. But our marsh is only an acre at most, and it doesn’t have enough of the preferred winter food trees–aspen, sugar maple, tulip poplar and willow–or the aquatic plants, forbs, and grasses that beavers eat in the summer. They also like flat terrain or valleys and large streams with enough water for damming. Like the mink, the beaver ultimately rejected our marginal beaver habitat, or so we surmised. Still, I searched the stream for several days before giving up hope.

Probably the beaver we saw was a two-and-half-year-old that had voluntarily left its parents’ lodge and was looking for a home of its own. But it was a couple months ahead of schedule according to the books I checked. Usually a mature beaver leaves its parents and younger siblings between April and September and becomes a floater segment of the population, following water courses as far as twelve and a half miles from its natal home in search of its own turf.

This beaver, like many of the wild creatures we encounter here, had not read the books and had instead set out on its own during February’s thaw, convinced by the sound of running water that spring was here to stay.