The Tenacious American Mink

February 28, 2024

This week, I had the good fortune to see an American Mink (Mustela vison) crossing in front of me with a giant gopher in its mouth. It darted out from Outlet Creek and disappeared into a bulrush wetland across the gravel road I was driving. There was no time to get my camera out; it was one of those brief sightings with no one around to collaborate. A few weeks ago, on one of our public tours, we saw a glimpse of what I think was the same animal in the same place, but it was raining hard, and we were not sure what it was. The mink I saw yesterday was in the midday sun and unmistakable. Seeing a new mammal (to the Mitigation Lands) is exciting, so I thought I would write about this tenacious hunter.

This mink is accurately described as “moving….like a brown silk ribbon” by naturalist Andy Russel. It has a sleek coat of either dark brown or black, usually with white spots on the chin, chest, and sometimes on the belly. The legs are short and the tail is tubular and not too bushy. Male minks are nearly twice as large as the females. Their anal scent glands produce a skunk-like odor which is used to mark their hunting territories. The males are hostile to intruders and fight viciously in or out of the breeding season.  Much of this information can be found in Tamara Eder’s book, ‘Mammals of California.’

The American Mink is in the weasel family and is almost as aquatic as an otter. They routinely dive to depths of ten feet or more in pursuit of fish. They are opportunistic and persistent hunters, eating a wide variety of food over all kinds of terrain. They are fierce predators of muskrats, but they will hunt gophers and have been found to eat voles, frogs, crayfish, waterfowl and their eggs, mice, rabbits, snakes, and aquatic invertebrates. Like other members of the weasel family, they occasionally eat chickens and other domestic fowl in farmyards.

Mink inhabit wetland areas of all kinds, including banks of rivers, streams, lakes, ditches, other waterways, swamps, and marshes. No wonder they live on the Mitigation Lands because we have riparian and streamside areas with banks for digging homes into. The large swathes of wetlands and wet meadows have plenty of voles and other rodents to eat. It is an ideal habitat for these active, cunning animals. Why we have never seen a mink on our wildlife cameras is a mystery. Maybe the cameras need to be placed on the creek banks very low to the ground where they dig their overnight dens. Minks den in protected areas near the water, often in a Muskrat burrow, an abandoned beaver den, or a hollow log. They also dig their own dens into the streambank. Dens are also used to store surplus food for later. Mink dens are always temporary.

The word “Mink” originates from the Swedish word that means “stinky animal.”