Sunday, December 2, 2012

Crazy Mink Antics at the Nature Preserve

Last January a female mink at one of the beaver ponds put on a pretty interesting show. She seemed to be staking a territorial claim on the pond and its ice fishing rights. It's quite possibly that she was also calling dibs on an uninhabited beaver lodge (well, it was uninhabited by beavers). I had been observing this particular mink for several weeks –as her visits to Sarah's Pond seemed to coincide with my own. Usually, she'd be busy fishing; diving down into a gap in the ice next to one of the flooded out buckthorn trees. Her method was to  stand on a broken off snag while staring intently at the hole in the ice. Without warning she'd plunge into the dark icy water. A minute later she would emerge from the same hole or from one nearby, shake herself off and the return to watching the water. Perhaps one out of every 4 times, she would come back up with a minnow.

The mink will continue to fish through the winter as long as there is a hole in the ice
None of that is particularly novel behavior. What was novel was her means of patrolling her claim. She would run around the perimeter of the pond again and again, diverting course to chase off any intruders. The poor muskrats seemed to be in the wrong place at the wrong time. I watched her pursed one over ice and then through the water. She wasn't trying to actually catch it; her effort was more to scare off what she perceived as competition. Sure enough after a few days of this stepped-up patrolling, the muskrats moved to another pond, and all of their fishing rights were inherited by the mink.
Dashing over the ice on the beaver pond
A few weeks ago, I watched a different mink engaging in the same behavior –dashing repeatedly around an ice covered pond and harassing muskrats. A few times while running her circuit she encountered me. Each time, she stopped dead in her tracks, peered at me with intense beady eyes and then dashed off again -resuming her circuit.
The Mink runs on the ice pursuing a swimming muskrat 
This mink didn't continue to lay claim to the pond and by the next day all the muskrats were back to their normal business. I think what discouraged the mink most was the fact that the beavers are so active in the same pond, and though they present no competition for fish (beavers are strict vegetarians), their high activity level and multiple work projects make them too much of a disturbance factor in the habitat. It would be a bit like living right next door to an guy with an excavating business, and a penchant for transforming his own yard.
Trying hard to get at the mouse nest inside the bird house
Yes, mink will climb trees. I've seen them do it. Many think that any weasel seen up a tree would more likely be a Pine Marten (a much rarer species), but mink are quite adept at getting around in the branches of a tree. In trees they seek out nests of mice, and chipmunks. Bird nests are also sought. Just this week I watched a mink climb up a pole that a bluebird box was mounted on, he wasn't after a bluebird though; this time of year, it's the White footed Mouse builds nests in many of these boxes.
The nest of a White-footed Mouse
The mink unsuccessfully tried to fit into the entrance hole. He then climbed all around the box looking for another way in. It looked like he had a piece of mouse bedding in his mouth at one point, but it may just have been his white chin patch that I was seeing.
Mink are excellent swimmers
Male mink are larger than females. They also hold a much larger territory –even over 1,000 acres. Their territories always sure to include an ample amount of streams and wetlands.


  1. fascinating post! I had no prior knowledge of mink or their behaviours.

  2. Hey, mink actually purr too, but I always seem to catch them when they're in a bad mood, and growling to themselves.