January marks the peak of winter cold and, by the end of the month, the daily average temperatures begin to trickle back towards sanity. Moreover, by late January, we can begin to hope for an occasional warm spell, even an above-freezing January thaw. The long, cold winter of 2008/2009 makes the occasional warm spell even more of a treat. These warm spells occur more and more frequently as the winter wanes into February and March. The warm spells and associated increasing day lengths also lead to observable changes in the natural world for those who carefully observe.
Perhaps the most improbable winter creatures are the so-called snow fleas. Snow fleas are tiny arthropods, belonging to a group commonly called springtails. They are common and easily observable on warm winter days near tree trunks or other plant material. They look like a sprinkling of pepper on the snow, but this pepper moves. Look closely and you will see them hopping about, using spring-like appendages under their abdomen. Snow fleas eat bits of decaying plant material and no, they won't hurt you or your dog. A sunny, 25 degree winter day suits them just fine. They contain a sort of natural antifreeze which allows them to survive sub-freezing temperatures. During warm spells, they become active and perform a miniature acrobatic performance right on the snow.
Plants also begin to sense the changing of the seasons. Red osier dogwood, commonly seen growing around the perimeter of marshes, begins to turn from a faint, grey-red to a brighter and brighter red. By late winter, the stems are cherry red.
Sap begins to move in trees during winter thaws. A brief thaw does no harm, but a long warm period followed quickly by another cold snap can lead to damage as the sap moves into the tree trunk but then freezes, splitting the bark and exposing the tree to pests and diseases. This is why arborists and orchardists sometimes paint the south side of a tree trunk white; they don't want the bark to warm up too dramatically during winter warm spells.
Many animals are highly visible on warm winter days. Some birds, such as blue jays and chickadees, begin to sing their spring territorial songs on the first warm, sunny days in late January. Chickadees whistle a loud "fee-bee" or "fee-a-bee". Blue jays make what birders call their pump handle song as they declare to the world that, come spring, this patch of yard will belong to no other. Pheasants find respite from the fierce winter days and spend time during the thaw finding food through newly softened snow or on patches of exposed field.
For some animals, a warm spell is simply a time when they can relax a bit and don't have to spend every waking minute searching for food. A pleasant winter day is a fine time to find a fox curled up on a snow bank exposed to the sun; the fox is neither cold nor hot and isn't so desperate for food that it has to hunt night and day.
Those marvelous and peculiar animals we call humans are more commonly seen outdoors during fine winter weather too. A warm spell in winter is a great time to explore, take a walk, check on the food plot you planted last spring, or follow a set of tracks in the snow and see where it leads. A warm spell is just the ticket to remind everyone of the promise of spring and the great flights of migratory birds coming in a few months to a patch of habitat near you.
Featured WPA: Swenson Waterfowl Production Area, Big Stone County
Swenson Waterfowl Production Area is a tiny, atypical WPA. It is a 16-acre sliver of a large marsh, with only a tiny patch of upland. Yet even such a peculiar bit of public land as this has value for people and for wildlife. Right now, frogs and turtles are resting on the marsh bottom, awaiting spring. Right now, sediments are settling out of the water column under the ice, creating cleaner water. Right now, water is slowly filtering downward through the soil and the glacial till underneath, recharging aquifers to provide a drink of cool, clean well water to some farm kid 40 years hence. Right now, this little piece of land is there for your enjoyment, ready for anyone with snowshoes and a bird book, a camera and a love of hoar frost, or a .22 and a taste for rabbit stew.
For a map of Swenson WPA or any other WPA in the Morris district, go to http://midwest.fws.gov/Morris.