Life in the Subnivian Zone (reprinted from 2/5/11)

 Authors note:  I wrote this piece on life under the snow a few years ago when we were having a wild winter on the Cape.  Now in 2015 history seems to be repeating itself and then some.  I thought, then, maybe it would be appropriate to print this again and let you know about the party going on down there!  Pat 3/5/15 where, even in TX if feels like it is in the teens today! 



With all the groaning so many of us are doing about this endless winter, it seems a good idea to point out a few creatures that are doing the dance of joy. Bring on the snow! May it last until May! For some, life in the Subnivian zone is sublime!

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And what is the Subnivian zone? It’s simply the area between the ground and the top of the snow-an area of “free-for-all” for the likes of voles, mice, and shrews. Just think of the protection they gain within the tunnels they dig there. The temperature stays fairly constant, as it might in an igloo. The wind doesn’t bother them but most of all, the Hawk and the Owl and all others who place them on the “Friday Night Special” menu, can’t see them.

I am sure I have shared with you before how, as the snow begins to melt here, you can clearly see the tunnels that wind back and forth over the fields. Today I came across one shaped like a large valentine. Obviously no one has equipped these critters with a GPS or a Surveying kit to plot the straight line. Theirs is a meandering path that takes them to where grass may still be found, or whatever food source they are after. Under the cover of snow, mice and their like can feel free to chew away on the bark of young trees. If you come upon a tree in spring that is mysteriously missing its bark at the bottom, you can be pretty sure that is what happened.

The tunnels do provide some security, more than just having to “run for your life” all the time, but the prey weren’t left without a few tricks of their own. Owls and fox, coyote and weasels all have excellent hearing and they can hear the party going on down there. Perhaps you have seen pictures of a fox or a coyote leaping in the air to pounce on the ground, with the hope of trapping the vole in the collapsed tunnel.

Bernd Heinrich in his book “Winter World” says that, owls, upon hearing the sound, dive-bomb down with their feet curled and can punch a hole in even the crustiest snow. Then, grabbing with their talons, they usually find the, not-so-safe-after-all, vole. But before you take pity on the poor vole, let me remind you that it can have up to 18 litters a year, with 5 young in a litter and those, are able to reproduce in a months time!Eh Gad! Be thankful the occasional fox or coyote can still rout them out.

Another pro-snow animal is the Ruffed Grouse.
Of course, its preference is for soft snow that has recently fallen and has some depth. To stay warm through the night, and stay out of the storm by day, they blast head first into the snow and disappear in a puff of flakes. They then tunnel a little way under and set up a nice, well-insulated igloo for themselves where they are warm and out of harms way The only trick here is that snow may melt and then ice over in cooling temperatures making it a lot harder to ”poof” your way out again. Also, one must assume they only try this with soft snow or they would be in line with many of our NFL players with some serious concussions.


Now, does any of that make you feel better? Not every living thing is groaning about the forecast. And when the snow in your area finally does begin to melt, you too can go look for “Where the Wild Things Were”. Possibly even finding out your yard wasn’t quite as tame as you may have thought it was.