Naturespeak A naturalist's view of the world

February 17, 2008

Veryclose Voles

Filed under: Uncategorized — wykes @ 8:39 pm

  A substantial layer of snow is a God-send for some animals. While a cold blanket of the stuff can spell hardship for the likes of turkeys, deer, and larger critters, the small and meek are comforted by its sheltering cover. Meadow Voles, being of the small and meek ilk, take advantage of snow cover to explore places normally off limits for foraging trips. You could say that snow allows them to eat without being eaten. This picture illustrates just how they do it.

  Among all the deer tracks you’ll notice a branch-like pattern of raised snow looking like a set of varicose veins bulging from the whiteness (excuse the anatomical reference, but it was the only one I could come up with). These are the runways created by Meadow Voles seeking greens out on an open lawn. Like bugs under a rug, the mice are able to tunnel out into the exposed grass and do so knowing that aerial predators such as red-tailed hawks, kestrels, or owls can’t see them. As the perennial protein choice of nearly every predator in existence, Meadow Voles strive to keep out of the food chain for as long as possible. Feeding out in the open is a sure invitation for early induction into the chain. Voles spend most of their time under the cover of high field grasses until snowfall draws them out into the shorter stuff.

   It has been shown that these nocturnal mice become more active in the daytime when living with snow insurance. This interesting snow tunneling pattern is a common late winter sight (here’s another set). You can see that the tunnels branch out from the adjacent field and provide a record of feeding sorties to and from the lawn. It seems that hungry voles are desperate for some luscious greens after a subsistence diet of dry shrub bark and seeds.

  Under the snow, the tunnels are shallow highways arched over with grass and their structure becomes visible once the snow retreats (see here).  The runways become littered with grass clippings and droppings – the mice finding no immediate need to be sanitary in these temporary alleyways. Meadow voles are voracious eaters and can consume 60% of their weight daily. Sometimes they even resort to cannibalism, but only under stress (as if life as a walking snack isn’t stressful enough).

  Meadow Voles, also known as Meadow Mice or field mice, are probably the most common and successful rodent in North America. They are found in field environs stretching from Alaska to the Midwest.  They are cylindrical in shape and covered with a dark brown pelt that lightens to a silvery sheen on the tummy (see here).  In hand (see here) they reveal their mousey good looks, but unlike others in the mouse clan they possess relatively short tails and ears. These short characters define them as members of the Vole tribe. The scientific name of the common meadow vole, Microtus pennsylvanicus, means “short-eared mouse from Pennsylvania” in Greek (the Pennsylvania part being where the original specimen was described by the 19th century naturalist George Ord).

  The snow cover that created the conditions that allowed us to see the tunnel evidence has vanished in the last two days.  The Vole that made them is likely dead by now, but worry not, for there are millions more to replace him.  Their tremendous eating capabilities are matched by their tremendous reproductive abilities.  A female can crank out 3-10 pups and get them out of the house in a little over a month before immediately starting on another batch. They are love machines making tunnels of love.

No Comments »

No comments yet.

RSS feed for comments on this post. TrackBack URL

Leave a comment

Powered by WordPress