I can bet big bucks on getting several questions about vole damage this spring after all our snow melts away and lawns again become the center of attention. This is because accumulations like we have had allow for an active and vast subnivean zone, the name given to the area between the Earth’s surface and the top of accumulated snow. The area on the surface and above is the supernivean zone.
I’ve noted before that the Earth’s stored heat moves upward in the fall and winter such that the temperature at the base of this subnivean zone hovers around 32 degrees. The area above the ground surface, now filled with snow, melts. This results in an area with a frozen ceiling. If you are a vole or a shew or a mouse traveling at your lawn’s surface, the ceiling of the tunnel created freezes in the same way, making a nice, cozy area in which to live, hunt and travel.
So, while you can’t see it, know there is a network of vole tunnels right at your lawn surfaces. Why tunnels? These creatures are brown and stick out like a sore thumb when on a white surface. Their tunnels allow them to live relatively protected and connect foraging areas to nests replete with dining, living and bathroom areas. Obviously, vole nests can be pretty elaborate; tunnels can be a hundred meters long or more. Voles have to memorize their layout or they could get lost.
In fact, voles get so snug that they even breed during the winter, which most mammals will not. Meadow voles — Alaska has two kinds, red back and meadow voles — often live in packs. Their traffic, their tunnel clearing and, frankly, the day-to-day living events are what causes your lawn to be damaged. Don’t worry, it is only temporary.
What isn’t temporary is the damage to young tree and shrub bark often caused by hungry red backed voles that like to nest around tree trunks. Stamp the snow down and compact it around trees and shrubs to prevent tunneling into this area and preventing this damage.
Unfortunately for voles, there are animals that have adapted to hunt them. Sometimes you can see weasels going after voles. These critters have long and slender bodies so they can easily move through a vole hole in the snow and through the vole-size tunnels. They hunt in the subnivean zone, but don’t live down there.
Foxes, on the other hand, hunt voles from the surface. They can hear movement and jump into the subnivean zone, catching prey even a couple of feet down. Coyotes eat an occasional vole and owls use their sense of hearing to hunt, find and catch voles. Add hawks to the hunt as well as tiny, short-tailed shrews which can easily move through these tunnels because of their diminutive size. They too, hunt voles. It is tough going for voles.
Voles are at the bottom of the food chain. They are said to be an interface between plants and animals because they’re mostly vegetarians — but will eat carrion, including dead members of their own species. Their populations fluctuate greatly, usually in three- or four-year cycles so the populations of their predators do as well. For this reason, the damage I will be questioned about this spring may or may not be serious. It will be there, however, and I know it will cause concern. Maybe this little note will diminish that somewhat.
Jeff’s Alaska Garden Calendar:
Alaska Botanical Garden: Tickets are available for Brighter Winter Nights, the Garden’s botanical themed lights display. Check www.alaskabg.org for ticket dates between Dec.1 and Jan. 20. Thank you ConocoPhillips for helping out. Lots of neat workshops. Early bird gets the worm!
Amaryllis: Get ‘em out of storage and water. Buy new ones.
Poinsettias: Keep slightly damp, slightly cool and out of drafts.