What do Mink do to Water Voles? (hint: it's not pretty) by Tom Moorhouse - Invasive Species Week

Tom Moorhouse is a fiction writer. When not writing he works as an ecologist at Oxford University's Zoology Department. Over the years he has met quite a lot of wildlife. Most of it tried to bite him. He loves hiking up mountains, walking through woods, climbing on rocks and generally being weather-beaten outdoors. Find out more at https://tom-moorhouse.com/ or follow Tom on Facebook https://www.facebook.com/authologist/.

I have spent far longer than most people trying to describe what American mink do to water voles. In fact I have written not just one, but multiple books on the subject. (This sounds obsessive even to me. But hey, it’s a living.) And so when presented with the challenge of writing an article on this subject I knew that my moment had come. Finally, my dream assignment!

With no further ado, I give you mink impact from two perspectives. The first is that of a water vole researcher (me) discovering for the first time that his study population might just have a problem...

            I arrived at the reserve to a strange emptiness. My traps caught half the number of voles I was expecting. The marsh ditches seemed oddly bereft of feeding sign and latrines. I was puzzled, and suspicious. The place should have been heaving as the late summer swelled water vole numbers but instead they seemed to be dwindling. And when I returned there in September, vole numbers were lower still. Finally, when I picked up a closed trap to find it disconcertingly light, I discovered why. Inside were water vole droppings, and carrot that had clearly been gnawed. The bedding was soaked and sticky. I reached in and pulled some out. It was wet, not with rain, or urine, but with blood. And down the inside of the trap were claw marks, as of a rodent that had been dragged out, scrabbling and fighting for purchase. And further down the dyke, near to a stack of browning feeding sign, I found a small pile of entrails and fur. The fur was instantly recognizable. It had once belonged to a water vole. I stared at these remains for a while before quietly completing my round. I let the remaining voles go with no more measurements or tagging. Then I shut the traps, packed up and told the guys at the reserve that a mink was eating their water voles.[1]

Yes. Look, factual accounts of conservation in action can be off-putting bleak, I admit it. (But oddly the rest of Elegy for a River, the book this quote is from, is actually quite chirpy and funny. Trust me.) So instead let’s explore a fictional viewpoint. How would an invading mink seem to a young water vole in their burrow?

            The terror came in the night. It came with swiftness. It came with teeth.

            Sylvan awoke with Orris at his shoulder. The burrow was dark and Sylvan was dazed from sleep. He began complaining, muzzily, but Orris silenced him.

            “Quiet. Listen,” he hissed.

            Sylvan listened. He could hear nothing but their sisters’ breathing and the ever present sound of the Great River. He peered into the darkness but could see nothing. Moments stretched away and Sylvan relaxed. There was nothing out there. Orris had probably had a nightmare or been scared by an owl or something. He was about to say as much when he too caught a faint noise. He strained his senses and it came again. Unmistakably, somewhere in the burrow, something was sniffing. He heard a soft scatter of footfalls. Then more sniffing. Sylvan’s hackles rose.

            “It won't find us. Just keep quiet.”

            But even as he spoke, the footfalls came louder than before, from a different tunnel. Sylvan's heart began to thump. The creature had found the back way that led up to the nest. The sniffing and padding grew louder, more eager, coming closer. Another, brief, silence. Then more steps, just outside the chamber. Then silence. Sylvan could not move, frozen to the spot with fear. Orris was silent but he could feel him shaking. A patch of darkness lightened, resolved itself into the tip of a nose. Sniffing, sniffing, unbelievably loud in the enclosed space.[2]

            Terrifying, I hope you’ll agree. These passages are taken from an adult non-fiction and a children’s fiction book, respectively, but both make the same point: that however you dress it, the impact of mink on water voles can only be described as “grizzly extermination”. And that is why mink control is an absolute necessity, underpinning any water vole conservation action.   

[1]     From Elegy for a River, by Tom Moorhouse, published in 2021 by Doubleday.

[2]     From The River Singers, by Tom Moorhouse, published 2013, Oxford University Press.

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