Tag Archives: snow

The sub-nivean zone

Hi all! Happy New Year! I wish everyone joy, peace, and health in the upcoming year.


And now, to start things off with a bang, check out my most recent Earth Matters column in the Hampshire Gazette (Jan 2, 2016). It’s about life under the snow:



Snow, snow, and more snow

"Novo mesto Breg 2". Licensed under CC BY-SA 3.0 via Wikimedia Commons
“Novo mesto Breg 2”. Licensed under CC BY-SA 3.0 via Wikimedia Commons

I am perhaps growing a little weary of the subject of snow, yet that is what there is this winter, in vast and ever increasing abundance. Snow, snow, and more snow. Lacking snow shoes, I wade through thigh-deep powder to the bird feeder, trying to keep up with the demands of little goldfinches, chickadees, and nuthatches. I sprinkle sunflower seeds under the feeder for the ground-feeding birds, knowing that, in fairly short order, those seeds will be covered up by yet more snow. I wonder how many of them get eaten, either from above by birds and squirrels, or from below by small rodents tunneling up from the sub-nivean world. Come spring, will I find a giant pile of soggy, uneaten seeds attempting to sprout? Several more months will pass before I’ll have an answer to that question.

In the meantime, some youthful part of me still gets excited by snow days. “What?? Snow day?? Everything’s closed!! No school!!” It’s been a while since I’ve been in school, but the excitement persists. In light of that feeling, here is fun poem by Billy Collins, entitled “Snow Day”.  Enjoy!


The sub-nivean zone

Well, the great blizzard of Ought Fifteen was a bit of an anti-climax here in my neck of the woods. Instead of the 27″-33″ that had been predicted, we got about 5″. I’m not complaining – the poor folks in Nantucket and Boston really got hammered – but rather am admitting to a mild feeling of let-down after all the water I bottled, the extra wood we sawed, and the emergency flashlights and candles I purchased. Ah well, at least we have another 5″ of snow, and, counter-intuitively, that actually makes for better winter conditions for our small wildlife friends, including moles, mice, voles (and their predators), various insects, and an assortment of bacteria and other microscopic life. This is because of the creation of the sub-nivean zone, which occurs after about 8″ of snow accumulation. (In case you are doing mental math, we had 3″ or 4″inches of previous snowfall, plus the additional 5″ish, leading to a total of 8″ or 9″.)

Entrance hole to the sub-nivean world. Photo by the Seney Natural History Association via Wikimedia Commons.
Entrance hole to the sub-nivean world. Photo by the Seney Natural History Association via Wikimedia Commons.

The sub-nivean zone (“sub”= under, “nivea” = snow) occurs in a protected area between the upper-level snow pack and the earth’s surface, where the temperature hovers around 32 degrees (F). The upper levels of snow provide insulation, while the lowest level melts slightly due to the heat from the earth’s surface, providing water and unfrozen food sources. Indeed, a whole winter ecosystem exists here, a fact that was not widely known until relatively recently. Rodents living in this zone create tunnels, air holes, latrines, and nesting areas, feeding on grasses, insect eggs, and whatever else they can find during the winter months.

The upper layers of snow hide rodents from the sight of predators, although owls can hear them running from 30 yards away, and foxes and coyotes can smell them. These predators will pounce through the snow, attempting to catch their prey with claws or mouth. You have no doubt seen videos such as this one, of a fox leaping into the air to try to pin a rodent through the snow:

(As a side note, according to the Discovery Channel, new research shows that if a fox is facing north (at least in North America), he/she is 75% more likely to be successful in catching prey through the snow than if facing any other direction. The reason for this is not fully understood.)

Weasels, more sneakily, slide down the rodents’ air tunnels and chase their victims through their own homes. (Don’t feel too bad for the little critters, though; if it weren’t for predators like weasels, our world would shortly be overrun with mice, voles, and other rodents, given how fast they tend to breed.)

Next time you are out walking in deepish snow, keep an eye out for traces of predators, such as fox jumps or owl/hawk punches. (In the photo below, note the marks left by the wing feathers and the hole punched through the snow by the bird’s feet.

bird wing snow
Photo by U.S. Fish and Wildlife Service via Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Snow_angel_%2811585439005%29.jpg

Alternatively, look near the base of trees or rocks for air holes leading to the sub-nivean world. (Please don’t disturb the holes, however; the creatures that made them have enough to contend with without our interference.)

For more information on the sub-nivean zone, see here:


or here:


Frigid morning

Woke up to a frigid morning. NOAA reported the temperature at -1 degrees (F) at 8:30 am, though my partner reported -4 in his car. Bad time to have run out of wood, though the oil is doing a surprisingly good job of fighting the bitter cold that presses against the walls and oozes though the windows. This house, though originally built in the 1840s, is much better insulated than our prior house, a 1790s drafty bucket with almost no insulation beyond some lovely double-paned windows. At almost 3K square feet, mostly closed off and unheated during the winter, we nonetheless went through 6-7 cords of wood a year. Yes, this new house is definitely an improvement.

A kind but strange neighbor generously donated a cord of wood to us not long after our arrival here this summer, but then spent several subsequent days staring longingly down our driveway. For a week or two, it seemed that he took daily walks by our house, hovering near the edge of the property like a hungry sparrow. I’m not sure he wanted the wood back so much as conversational opportunities, but his behavior was so odd that I took to staying in the house every time he came around, and finally he gave up. I felt a little guilty, but do not plan to be held hostage by anyone’s generosity, whatever the motivation. I hope he has found some friends.

Anyway, yes, it is frigid this morning. En route to collect the last, skinny maple logs, I found a number of tracks in the snow. What do you think they are? (The first 5 photos are all the same animal.)