Common mink

Mink are intelligent, curious, and fierce mustelids who are top predators in riverine ecosystems in North America. Around two feet in length, mink weigh only 2-3.5 pounds (Virginia DWR).

A mink dries off after emerging from a Shenandoah tributary

Investigating the creek banks

Catching an invasive virile crayfish

A mink climbs a tree over a cove

Mother mink transporting kits

Mother mink with kits in tow

Mink kits climb over each other while crossing a log

This kit was temporarily separated from the group

While on the hunt, these lithe predators patrol the banks of the Shenandoah and its tributary creeks. Over the last fifteen years, I’ve been documenting mink behavior in the Shenandoah River watershed in rural Virginia. Direct observation has led me to a greater understanding of the habits and ecological relationships of these secretive creatures.

Bright, curious, and fierce, a mink looks out from a muskrat hole.

Portrait of a mink

Looking somewhat bedraggled after emerging from the water, a mink poses on a submerged rock in the North Fork of the Shenandoah

On the hunt, an American mink patrols the edges of the river, periodically diving under the surface to look for prey.

After diving for prey, a mink emerges with a meal of fish.

A beaver lodge provides shelter for muskrats and also draws in a curious mink (a potential muskrat predator).

A mink makes its way down an abandoned railroad right-of-way close to the confluence the North Fork of Shenandoah River

A mink enters a tributary creek of the Shenandoah

Mink Ecology

While there are extensive studies on mink in fur farm contexts and as invasive species (escaped from mink farms on other continents), there are relatively few studies of mink ecology and behavior in their wild, native range.

Research has shown that mink populations may be correlated with muskrat density as well as crayfish “hotspots” in the summer months (Wolf et al.). I observed a mother muskrat and her five kits preying extensively on huge virile crayfish (Faxonius virilis), in the North Fork of the Shenandoah and a tributary creek. This prompts questions about the impact that native semi-aquatic species like mink may have on controlling invasive populations. Mink may also keep muskrat populations in check, which in turn, could positively impact the retention of crucial wetland plants.

Threats to mink populations include habitat fragmentation and climate change. Mink patrol linear territories corresponding to creeks and rivers (though some populations also inhabit permanent wetlands). However, development and roads have interrupted connectivity between riverine environments (Ahlers, et al.).

Climate change may cause greater fluctuations in water levels, creating unpredictable environments for mink populations.

While other semiaquatic animals such as river otters and beaver have been extensively studied, American mink are relatively mysterious. Mink deserve positive attention. They are far more than the invasive villains of European streams or the abused “products” of fur farms.

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Sources

Ahlers AA (2015) Habitat selection, survival, and disease risk of semiaquatic mammals in a highly altered landscape. Dissertation, University of Illinois, Urbana-Champaign

Ahlers, A.A., Heske, E.J. & Schooley, R.L. Prey distribution, potential landscape supplementation, and urbanization affect occupancy dynamics of American mink in streams. Landscape Ecol 31, 1601–1613 (2016). https://doi.org/10.1007/s10980-016-0350-5

Wolff, Patrick J., Taylor, Christopher A., Heske, Edward J., and Schooley, Robert L. Habitat selection by American mink during Summer is related to hotspots of crayfish prey. Wildlife Biology, 21(1) : 9-17. https://doi.org/10.2981/wlb.00031

Muskrat and mink populations key to good marsh management https://www.farmanddairy.com/columns/muskrat-and-mink-populations-key-to-good-marsh-management/525727.html

Common mink
Mustela vison mink