Winter Observations – 2007

Winter (with snow, please):

We finally have some winter out there complete with snow days off work and school and temperatures hovering in the plus and minus single digits. Even though its cold, it is still an excellent time to go out and see the campus nature trail. Last week I was out on the trail checking out some tree growth sites with a student. We got a bit chilly, but saw yellow shafted flickers, red tail hawks, chipping sparrows, several acrobatic squadrons of crows, and lots of deer, turkey, and vole tracks. Oh, and the trees are doing fine, too.

In February 2000 (which was the last February that we had such a good snow pack), I put together a walk on the trail in the winter and published out on the Virtual Nature Trail web site ( You can get a glimpse of some of the great things to see in the woods in the winter and still keep your feet and fingers warm.

Last Tuesday, Deborah Sillman was down on the Roaring Run trail in Apollo and saw 30 or 40 adult, winter stone flies out on the snow. These individuals were experiencing their short, adult portion of their life cycles in which they mate, lay eggs in the cold, oxygen-rich river water, and then die. Their nymphs will hatch out and live for one to four years under the rocks in the river. They eat algae and, for some species, small aquatic insects. The presence of stone flies along the Kiski River is very good news indeed! Stone flies are very intolerant of even low levels of water pollution. The water quality of the Kiski is steadily improving from its long history of human use and exposure to acid mine drainage.

Along the campus nature trail you might also see, on sunny, cold days, black “snow fleas” hopping around on the surface of the snow. These “fleas” have nothing to do with the ectoparasites of our dogs and cats, but are, instead, representatives of an old (over 400 million years old!) line of wingless insects called ‘collembola” or “springtails.” These tiny (1/16 to 1/8 of inch long), dark colored insects live in the soil and leaf litter layer of our nature trail forest all year round but, for some reason, become quite active on sunny, snow covered days (or, maybe that’s when we see them!). They hop around on the snow surface probably accomplishing dispersal of their numbers through their forest floor habitat.

Another interesting observation on these great snowy days involves a little known component of the forest floor called the “subnivian space.” The subnivia is the tiny space that forms in between the oil and litter layer and the bottom of the snow cover. I wrote about this space some years ago (subnivia essay) and had the occasion just yesterday morning to watch my dog (“Kozmo” to all of you who know him…you may remember his run-in with the skunk last year) spend over an hour completely entertained by the prospects and occupants of the subnivia. I have two bird feeders in my front yard and a significant accumulation of black oil sunflower seeds on the surface of the snow just under the feeders. I noticed that Kozmo was intently sniffing the snow surface just to the outside of the sunflower seed circle. He frequently leaped at the snow with his front paws and vigorously dug down all the way into the underlying soil (there goes my yard again!). He was after the shrews, and mice, and voles that were using the subnivia as a protective passageway from their burrows under the surrounding arbor vitae to the bounty of the scattered sunflower seeds.

I’ll be writing more soon. The robins are due back any day! Spring is coming!

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