Looking for Weasels

Identification Tips Inspired by a Visiting Weasel
Short-tailed Weasel in Summer

This story begins not in the woods, but in my kitchen. I was sitting at the table one morning when I caught a quick movement out of the corner of my eye. Living in an 1850s farmhouse, with a granite block foundation and more than a few cracks and crevices in the floors and walls, we occasionally see mice and voles inside. Turning to see if I could get a better look at whatever critter it was, I saw a head pop out from under the stove. Only getting a nanosecond glimpse of it, the first thought that crossed my mind was "what’s a ferret doing in the house?" which quickly changed to "we don’t have ferrets around here, that’s a weasel!"

Which Weasel?

The short-tailed weasel (Mustela erminea) is one of two native weasels in New Hampshire; the long-tailed weasel is the other. The state also has healthy populations of a number of other members of the weasel family (scientific name Mustelidae), including mink, fisher, otter, and striped skunks. The pine marten, also in the weasel family, is found in lower numbers in the northern part of the state.

The short-tailed weasel is also known as ermine, though the winter pelts of both the short-tailed and long-tailed weasel are called ermine in the fur trade. Both species are brown with white bellies in the summer, and turn all white in winter with the exception of the black-tipped tail. The white winter coat makes weasels especially difficult to see on a winter walk in the woods. Though the short-tailed weasel has a somewhat shorter tail than the long-tailed, and the long-tailed weasel is generally larger than the short-tailed, it can be difficult to tell the two species apart. Male weasels are significantly larger than females, and a male short-tail can be similar in size to a female long-tail.

The short-tailed weasel’s range extends north into Canada and Alaska, while the long-tailed is found in continental US and as far south as the tropics.

Weasels have long narrow bodies, short legs, and short fur, and are known as fierce predators. Having high metabolisms, they are constantly on the move looking for prey to satisfy their appetites. They hunt regular territories and cover a lot of ground, with male weasels travelling up to three miles in a night, though ranging no more than a mile and a half from their den. Weasels move fast and their narrow bodies allow them access to crevices, holes, and dens. The majority of their diet is mice, voles, and shrews, but they’ll also eat cottontail rabbits, small birds, snakes, frogs, and anything else they can catch. Like most predators, they’re opportunists. They’re known to wipe out an entire hen house worth of chickens in a night if they get the chance.Mouse

An Interesting Adaptation

Weasels are generally solitary animals, except during mating season or when females are raising the young, which they do on their own. Mating takes place in late spring or early summer. Once the egg is fertilized, it undergoes what is known as delayed implantation – development of the embryo stops for the next eight to nine months, after which the egg is implanted in the uterus wall and development begins again. The kits, an average of six per litter, are born the following April or May. This process is thought to be beneficial to the weasels because mating and giving birth both take place during the spring and summer, when prey is abundant. This allows for the mother weasel, well-fed from summer’s abundance, to carry her young through the lean times of winter. Then she gives birth the following spring when plenty of food is again available for the kits.

Habitat

Weasels are found wherever their prey is abundant. Young brushy forests, shrublands, open fields and meadows, wetland edges, rock piles, stone walls, and brush piles all provide weasels and their prey with a place to live and hunt. A landowner can create these habitats by clearing patches in the woods or by delaying mowing of fields until the end of the summer or even for a few years, building brush piles from tree branches and landscape trimmings, maintaining stone walls, and leaving some larger downed logs on the ground. Mice and other weasel prey aren’t attracted to neat, tidy landscapes, so the messier the better. In fact it’s a good rule of thumb for creating habitat for most wildlife species, not just weasels and their prey.

Not the Top of the Food Chain

Though weasels are highly effective predators, they aren’t at the top of the food chain. Weasels are killed and eaten by fox, mink, coyote, bobcats, hawks, and owls. One theory about the black tip on the weasel’s tail is that it entices predators to strike at it, causing them to miss and the weasel to escape to hunt another day.

So, was it a weasel I saw in my kitchen? I’m not really sure. It was such a quick glimpse, it may have been a chipmunk. I’d be a lot more comfortable with a weasel in the house, though, because a weasel won’t chew my wires or insulation. My wife, on the other hand, who normally doesn’t wear shoes in the house, decided to put her boots on that day.

We haven’t seen the weasel, or whatever it was, again, but we’ve certainly seen some mice. The cat isn’t any help at all in controlling rodents, and the dog, well, he just wants to be friends with everyone. Just ask the fox on the hill behind the house. So, a weasel would be welcome to pass through once in a while, as long as it leaves the chickens alone….

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