Bringing Home The Bacon (or frog)
Mink spend much of their time foraging in saltwater marshes, swamps and small wooded streams. They are excellent swimmers, and can swim to a depth of over 18 feet and for a distance of 100 yards. Fish make up roughly 40 percent of their diet, but they also prey on frogs, snakes, rabbits, squirrels, mice, chipmunks, muskrats, crayfish, insects and snails, among other creatures. Like other members of the weasel family, mink kill large prey with a bite to the nape of the neck.
The pictured mink swam to the ice-littered bank of an open stream, crawled under a large slab of ice and emerged minutes later with a very muddy frog in its mouth. With a foot of snow on the ground and mostly frozen wetlands, it was unquestionably a hibernating frog that the mink managed to unearth.
Sometimes mink eat their prey on the spot, or carry it back to their dens. It’s possible (though fairly early in the season) that once this mink arrived at its den it was greeted by up to ten offspring (each the size of a cigarette when born). The parents typically raise their young in a stream bank cavity roughly a foot in diameter which they line with fur, feathers or plant material. The family stays together through the summer and can sometimes be seen foraging together prior to dispersing in the fall.
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The Sniff Test
When your quest is to find out as much as you can about the identity, activity, diet and territory of your four-footed neighbors, it is logical to make the most of all your senses. Tracks can be seen, scrapings and bite marks on a tree can be felt and yes, one’s sense of smell can enhance any tracking expedition. Just as the tracks and scat of different species of animals have distinctive characteristics, so does the urine of different animals. Scent marking, including urination, is a behaviour used by animals to identify their territory, and therefore a highly visible sign in winter.
At this time of year, foxes are breeding, and without even putting your nose near where a fox has marked his territory with urine, you can detect its skunk-like odor as you pass by. If you’re so inclined (and I realize many readers may not be) you can heighten your sensory experience as well as your identification prowess by sampling the smell of other animals’ liquid waste. White-tailed deer urine has a pungent, piney smell, quite pleasing to this naturalist’s olfactory receptors. You can detect a porcupine den from a considerable distance by the pungent, very distinctive but hard to describe odor of its urine (which spills out onto and coats the bark of a tree den, thereby advertising the porcupine’s presence). Coyote urine smells very much like a domestic dog’s, and members of the weasel family often have musky-smelling urine, though a recently-sniffed fisher marking had very little scent.
Needless to say, it’s a lot easier to discover and sample urine when there’s snow on the ground and it is more evident. Virginia opossums, snowshoe hares, red and gray squirrels, eastern coyotes, red and gray foxes, raccoons, fishers, mink and striped skunks are all in or entering their breeding seasons, when scent marking is more frequent. Snow is currently on the ground, at least in northern New England. It’s prime time for olfactory activity, if you’re game. (Photo: stump marked by a red fox)
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Mink and Fisher Tracks
As members of the weasel family (Mustelidae), Fishers and Mink have five toes on both front and back feet. Often all five digits do not register, but in prime tracking snow, you can sometimes see them. Typically, mink tracks are found near a body of water, and fisher tracks are found under a canopy, not in the open. Where you have both water and trees, it’s possible to see signs of both animals.
In general, the larger the animal, the larger its tracks. Mink weigh one to three pounds; fishers four to eighteen pounds. In this photograph, the mink tracks (smaller, in the middle) are heading towards the top of the photograph, and the fisher tracks (top most and bottom most) are heading towards the bottom of the photograph. They were both traveling on a frozen woodland stream.
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Mink Exploring Streams
The pattern of diagonally-paired tracks indicates that it’s likely that a member of the weasel family has been travelling on top of this mostly-frozen stream. The presence of water makes it likely that a Mink made them. For the most part, Mink are restricted to forest cover and ponds, streams and rivers. When bounding, their hind feet register almost exactly where their front feet were, creating this double-print pattern.
Many members of the weasel family, including Long-Weasels, Ermine (Short-tailed Weasels), and Fishers, also make these paired tracks, especially in deep snow. Size is one way to discriminate between them, with the size of Mink tracks (1 ½”-long) falling in between 3″- long Fisher tracks and 1”- long weasel tracks.
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American Martens in Northern New England
American Martens (formerly Pine Martens) are making a comeback in northern New England. On New Hampshire’s Threatened Species List, and on Vermont’s Endangered Species List, American Martens are rebounding from the effects of habitat loss and trapping in the early 1900’s, but are still considered rare. This medium-sized member of the weasel family is slightly larger than a Mink and smaller than a Fisher, and often has a light orange bib, or throat/chest patch. Lighter fur usually is found on their head and along the edges of their ears. In addition to a pair of scent glands, which all weasels have, American Martens have a glandular area on their lower abdomen that exudes a musky-smelling, oily secretion used for scent marking.
American Martens spend a lot of time in trees. Their semi-retractable claws help them climb and hang onto branches. In addition, their hind limbs can be rotated at the ankle (like Gray Squirrels) to allow them to descend a tree very quickly, and their long, bushy tail helps them balance.
Because they store very little fat, martens must hunt every day. In the winter they are active for about four hours a day (14 hours/day in the summer), and during this time consume an average of three voles or the equivalent amount of chipmunks, birds or other small rodents. A sighting of an American Marten is a highly-prized experience. (Thanks to Laurie Stokes, whose photo of a Pine Marten was taken in the White Mountains of New Hampshire.)
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Mink Meanderings
As these wet footprints and tail drag marks indicate, mink are excellent swimmers, and spend a great deal of time in all seasons foraging in and along streams and ponds. As a rule, all weasels can often be found close to water, as they drink often, though relatively little at a time. But mink do far more than drink water – they find much of their prey, including crayfish, frogs and fish, in it and are very well equipped to capture them. Mink can swim underwater to a depth of 18 feet and they can swim as far as 100 yards. Look for their tracks going in and out of openings in the ice that covers much of a stream’s surface this time of year.
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Mink Slide
There is nothing like heading out on snowshoes to look for tracks after a major snow storm has passed. The pristine snow is often untouched, except for a few brave souls who have ventured out. Most of the mammals that are active in winter hunker down until well after it has stopped snowing, but the mink (Mustela vison) is not about to lose a night of hunting and its tracks can often be found the morning following a storm. Like other weasels, this bounding carnivore often leaves diagonally paired tracks, but unlike other weasels, its tracks are consistently the same distance (1 to 3 feet) apart. They also are most prevalent in or near wetlands. Although a fierce predator, the mink also has a playful side, much like its cousin, the river otter. Mink are known to dive under the snow and make short tunnels. Even more delightful to come upon are the slides that mink often make down inclines. If you see a groove in the snow about 3” in diameter, with paired tracks at either end, you have come upon such a slide.
Fisher and Mink Tracks
As members of the weasel family (Mustelidae), fishers and mink have five toes on both front and back feet. Often all five digits do not register, but in prime tracking snow, you can often see them. Typically, mink tracks are found near a body of water, and fisher tracks are found under a canopy, not in the open. Where you have both water and trees, it’s possible to see signs of both animals. In general, the larger the animal, the larger its tracks. In this photograph, the mink tracks (smaller, in the middle) are heading towards the top of the photograph, and the fisher tracks (top most and bottom most) are heading towards the bottom of the photograph. Although not pictured here, both of these carnivores engage in snow sliding, much like their cousin, the river otter, and the resulting grooves are occasionally found when the snow is a bit deeper than it is now.
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