For years I have went the extra mile for pictures of otters, mink, fishers and weasels.
Usually, my efforts go un-rewarded (they are a difficult group to camera trap 'round these parts!)....and although I've had some success with otters and mink, the others have eluded me.
Occassionally, though....one gets lucky.
I *believe* this is a Long-tailed Weasel (Mustela frenata). Unfortunately, the animal is pretty far away, but there are a few lines of evidence that would suggest M. frenata to me. This species is slightly larger than the other weasels found in our area: the Short-tailed Weasel (M. erminea) and the Least Weasel (M. nivalis). They can reach lengths of 18 inches and, based on the distance this one is from the camera (which would be about 15 ft), the size would indicate it's a Long-tailed. Furthermore, according to Long (2008), the tail has a very distinct black tip, which is fairly obvious from these clips. Now....the Short-tailed Weasel also has a black-tipped tail, but it is generally not found this far south. Furthermore...and also according to Long (2008)......if the tail length is 1/3 or greater of the body length, it's a Long-tailed. From what I can tell in this video clip, the tail length conforms with what I'd expect for M. frenata.
Yet...there is one more wrinkle in all of this.
This part of the state is also the unnatural home of a Mustelid introduced from Europe: The Stone Marten (Martes foina). It was believed to have been introduced by a fur breeder in the '40s, and although apparently established, is not common. For example, reports have trickled through that a few have been captured annually for roughly the last 15 years (Long 2008). The Stone Marten's dorsal and ventral surfaces (or back and belly) are concolor (or...of one color), although, the limbs and tail fur is apparently slightly darker than the dorsal fur. All three weasel species native to the area are bicolored (of two colors): with a brown back and a cream or buff belly. Stone Martens do have a striking white patch on the throat, but no black-tipped tail.
It's hard to see for certain in this video, but I don't believe there is an obvious white patch on the throat of this animal...and it also doesn't appear that the belly/back are the same color. Then...of course....there's the fact that the individual in these clips has a black tail.
Anyways.....I'm leaning towards Mustela frenata.
People are not kidding when they refer to weasels as bundles of energy. Look at that thing go!
They have to be that quick if they want to catch some of their preferred prey items (which are also very quick) and avoid being eaten themselves. Weasels prey upon many types of small animals, ranging from insects and snakes to small mammals. Yet, rodents are often a favored dish. In fact, they so frequently dine upon mice, that this behavior is even reflected in their genus name (Mustela), which translates to "one who carries off mice" (Cold 1998). Long-tailed weasels are excellent examples of dietary generalists, and apparently readily switch to alternate prey when normal prey densities are to low. According to a review by Sheffield and Thomas (1997) these generalist behaviors have resulted in their relatively stable populations.
Another cool thing about weasels and their relatives is that they don't shy away from bigger fare. They are well-known to take down an animal as large as a cottontail. Check out this footage of a "Stoat" from BBC's oustanding series LIFE, which includes a stunning series of one killing a rabbit (warning: this footage may be too intense for some viewers, but it is amazing!).
Note: "Stoats" are apparently the common name used for Mustela erminea throughout the rest of the world, although in North America we refer to it as the Short-tailed Weasel (King and Powell 2007).
So....no question: weasels are very neat little critters.
I have never actually seen a Long-tailed Weasel before. I've encountered Least Weasels several times in the past. Well........I'm assuming they were Least Weasels given the fact that Leasts are found in the southern part of the state and like grassy or marshy habitats/forest edges where I encountered these (Long 2008).
The weasels that I encountered were captured.....basically by accident. They were all captured in funnel traps that I had along drift fences to catch snakes (this would have been back in 2006-2007). We had been running these surveys for an entire summer and had been catching many small rodents in the funnel traps, in addition to snakes. Then...suddenly....for a breif period (maybe a week or two), I caught four Least Weasels spread across two sites.
Two were completely alive and kicking (in fact, they basically ran circles loop-de-loop style inside of my minnow traps when I picked them up). They were gone in the grass the second I opened the trap.
One, unfortunately, was dead upon my arrival (died from exposure), which I felt terrible about.
The last individual appeared dead (at first) when I picked the trap up. However, closer inspection revealed that he was still alive, but appeared groggy and suffering from stress/exposure/dehydration. I didn't know exactly what to do...and of course I had no special gloves or anything with to deal with a critter like this.
But...against sound judgement.....I took it back to my car (in the trap). I found a pair of extra socks in my car and placed the weasel inside one of my socks so that his head was poking out. Then I poured a bit of water into the bottle cap from one of my water bottles and barely touched his chin with the water. Immediately, the weasel started lapping the water up. I continued to fill the little cap as long as the weasel would drink....and quit when he sort of coughed/sneezed a bit from the water.
I tried to come up with some sort of a plan for this little guy. He was still groggy (eyes closed), breathing seemed regular.....but he was listless. I called a nearby vet clinic, but they said that they didn't deal with injured wildlife. They told me to contact the Humane Society in the area....which I did only to find out they were closed.
So, there I was....with a sleepy-looking weasel in one of my socks on the front seat of my car.
Not knowing what else to do, I waited. Eventually, the animal seemed to start perking up. He opened his eyes, became semi-alert and looked like he might want to move.
At this point, I took the critter (in the sock) back out to the field location near the drift fence. I found a nice protected spot under a dense growth of dogwood and placed the weasel there (in my sock). I watched for a minute...but decided I didn't want to stress the animal out any more...so I walked away.
Several hours later, I came back to find my sock laying there....uninhabited.
I hope that means the little weasel went safely on about his way.
King, C.M., and R.A. Powell. 2007. The Natural History of Weasels and Stoats: ecology, behavior, and management. Oxford University Press.
Long, C.A. 2008. Wild Mammals of Wisconsin. Publication No. 65 of the Museum of Natural History, University of Wisconsin-Stevens Point. Pensoft Publishers, Bulgaria.
Sheffield, S.R. and H.H. Thomas. 1997. Mustela frenata. Mammalian Species no. 570. Published by the American Society of Mammalogists.