Outdoor Notebook: Animal winter survival is a wonder
Each year when the mercury plunges to the extent that it is hardly visible we begin to think about the wildlife in our area. At our house, Judy will stand by the window near the bird feeder and wonder aloud how the birds can survive. We look at those little feet that are wrapped around twigs and think about why they don’t freeze. Bird’s feet are made up mainly of bone, sinew and scale with few nerves. They have an adaptation consisting of a network of arteries that carry warm blood from the bird’s heart that is interwoven with veins that carry cold blood from the feet and legs. This interweaving warms the cold blood in the veins before it reaches the bird’s heart. Therefore the bird’s legs and feet stay warm. Our discussions about how birds stay warm results in discussions about other wildlife.
Some wild creatures are able to survive quite easily in the frigid cold that we have put up with recently. At one time when wild turkeys were being reintroduced to our state we were told that there would never be a huntable population in northern Wisconsin. We were further told that the winters in northern Wisconsin were simply too harsh for turkeys to survive. It appears that nobody informed the turkeys that they were not able to survive in our area. Although there are some winters during which we lose a lot of turkeys we indeed have a huntable population. There are some days when the sun is out we are able to see flocks of turkeys feeding in farm fields. We recently saw several flocks as we were returning to Rhinelander on Hwy 51. One condition that makes it difficult for the birds to get enough food is when a thick crust forms on the snow. We have been told that turkeys will eat anything that they can fit in their mouth. Oak ridges provide a good feeding area for turkeys to scratch the snow looking for acorns.
The ideal situation for grouse during the extreme cold, such as we survived recently, is soft snow that is about a foot deep. The grouse dive under that soft snow and are able to survive where the temperature is several degrees warmer under there than in unprotected areas.
Grouse spend a lot of time eating the buds of male popple trees. Now I cannot tell the difference between a male popple and a female popple tree however it is apparent that the grouse can.
Several times when we still enjoyed the company of a lab, who seemed to enjoy running in the snow, we were surprised by a grouse. While walking in the woods on snowshoes a grouse would flush out from the deep snow and fly off. That experience would cause our heart to skip a beat or two. The look on Bert’s face when a grouse would explode from the snow in front of his paws was great. Sure do miss that dog!
Some animals are perfectly suited to live in the climate of northern Wisconsin. Perhaps the best example of this is the whitetail deer. It is probably the most studied wild animal in northern Wisconsin and there are several studies in progress now.
In winter the whitetail’s coat consists of stiff, hollow guard hairs that are quite long and dark in color and a very fine but deeper, wooly under-fur. Although the guard hairs tend to absorb some solar radiation because of their dark color, it is the density of the under-fur that makes the winter coat so highly insulative.
When cold temperatures and wind chill become severe whitetails in northern habitats burn more calories in daily maintenance than they take in as food, requiring deer to live on accumulated body reserves. Deep snow causes this process to be accelerated when deer try to move.
During the fall rut deer may lose all or most of the fat they accumulated prior to autumn. For them, consuming energy through the course of the ensuing winter season will be particularly critical.
Deer will migrate to sheltered areas when deep snow hampers their movement. Preferred areas for the deer to gather are cedar swamps. These areas referred to as deeryards provide shelter as well as food. When deer are forced to the yards early and the snow lasts into the spring they may be in a situation where they over-graze the trees late into the year.
This year we have had snow since early in the month of December and some very cold temperatures since early in January. We will attempt to keep track of the condition of our deer herd as winter progresses.
A local deer hunter had an interesting experience during the recently completed antlerless four-day hunt. The hunter was sitting in a ground blind thinking about how cold he was when a doe walked toward him. He put the scope on the doe’s front shoulder and pulled the trigger. The gun went click but did not fire. He worked the action and tried another shot. Again the gun went click. He worked the action again and put his chemical hand warmer on the chamber and let it lay there for about five minutes. The doe still stood there. The hunter pulled the trigger for a fourth time and doe dropped in her tracks.
Longtime Northwoods outdoors personality Roger Sabota writes a bi-monthly column for the Star Journal.