What was the critter in the mousetrap?

The mystery began with a mouse trap clapping shut.

It ended with me walking across a mown hay field in the rain, leaving a three-day dead meadow vole behind.

In between, I learned field guides and photos are no substitute for having an expert see the object at hand — in this case, a short-tailed brown-furred corpse.

And, I learned, as always, how much I don’t know.

I live on the edge of the country — the exurbs. You live in such a place, in an old home, and you get mice as fall invades, looking for a safe haven from the cold. Hence, the mousetrap. The mice I catch are whitefooted mice — small, gray, reservoirs of Lyme disease bacteria. Once caught, I chuck them in my compost bin. I waste not a tear for them.

But last Monday, in the evening, I checked the trap and found something unmousey there.

It was brown with a white belly, with a round head and small ears. It was chipmunksized — bigger than a mouse. And it had a very short tail — maybe an inch long.

I did not toss it. I wanted to find out what it was

My guide books were unhelpful. They pointed me to a Southern bog lemming — a chunky brown rodent with stubby tail.

This did not make sense to me. The bog lemming is uncommon in the state, listed as a Species of Special Concern. It does not show up into anybody’s house seeking shelter, even with winter coming on.

My bird-watching instincts also kicked in: If you think you see something rare, it probably isn’t. Check out the common species first.

But still … maybe … a lemming. How cool would that be?

A more likely ID, I realized, would be a vole — especially an all-brown meadow vole. But the pictures in the guidebook showed them with a tail twice as long as my trapped guy.

My skills as a photographer are as terrible now as they ever have been. Which is why I drove to my friend John Pirro’s house, carrying a brown dead rodent. He is a very good photographer and he got a much better image of my rodent’s remains.

But what was it? Looking at the pictures, urban wildlife expert Laura Simon guessed woodland vole.

Jenny Dickson, director of the wildlife division of the state Department of Energy and Environment Protection, opted for a Southern redbacked vole — common, heavier than a mouse and a likely home invader.

But she said, see if James Fischer, the research director of the White Memorial Conservation in Litchfield, would take a look at it.

“If he thinks it’s something else, then I’ll go along with that,” Dickson said.

Luckily, Fischer was in and willing to look. So again, I drove off with my little dead friend wrapped in a paper towel beside me.

He looked it and said, immediately, “It’s a meadow vole.” He then took the vole up to his office and studied its teeth under a microscope to make sure. Lemmings have grooved incisors. My vole’s teeth were ungroovy. It was also a male, he said.

And what of the cause of my confusion, the short tail?

“It’s been bobbed off,” Fischer said. Some accident, some run-in with a predator left it with half a tail.

Meadow voles — Microtus pennsylvanicus — are the most common vole in North America with a range from Alaska to the Canadian Maritimes and south to New Mexico and Georgia. They are prolific breeders, with females able to churn out a new litter every three weeks or so.

And they, and all their little rodent friends, are incredibly vital to our ecosystem, Dickson said. They’re seed spreaders. They help with woodland decomposition by chewing their way around the forest floor. And they are a major food group for predators — foxes, coyotes, bobcats, owls, and hawks.

In the past, I’d known voles as the things that chewed up a third of the potatoes I’d planted — a curse-worthy little bugger and not much else. Now I was holding one in my hand.

What to do? I took a detour on my way home to a field bordering open space land in my town. And there, I left my vole hoping a fox or owl would find him and gobble him up.

Better that, I thought, than to putrefy in my compost bin with onion skins, eggshells and dead mice for company.

This is the critter found in Robert Miller’s mousetrap. At first he thought it might be a lemming, because of its short tail, but a wildlife expert’s examination determined the creature was a meadow vole.