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Twas the night before the winter solstice, and all through the refuge, the creatures were quiet – the eerie difference was huge. Many critters go south, but some stay through the winter. How do they survive? Hmm, that’s a thinker! From running wild to going into torpor – it's all quite the chore!
The forest and prairie are quiet. The wetland is freezing over, and a thin blanket of snow covers the ground. In a warm tree cavity, a cozy underground burrow or even nestled under your porch, you may find raccoons sheltering from the cold winter temperatures. You might think to yourself, “they’re hibernating!”, but their snug winter lifestyle is actually slightly different. Cozied up in their den with leaves, sticks or garbage, raccoons will enter torpor, temporarily lowering their body temperature and energy use. Raccoons will sleep for days or weeks with their fuzzy tails wrapped around themselves for warmth. In torpor, their body temperature will not drop as low as it would for animals that go through hibernation. Even though they are sheltered in their safe den, raccoons will brace the bitter cold air in search for food when they wake.
Although the forest is still as raccoons enter torpor, the ice over the wetland is rapidly growing, covering more of the water each frigid day. With a solid top and no opportunity for oxygen to mix into the water, how do fish, turtles and other aquatic animals survive the winter freeze? The top layer of ice, thin as paper or thick as wood, acts as insulation to retain some heat in the otherwise icy water. In the ponds, lakes and streams of Minnesota, warm water sinks and provides a spot for schools of fish to gather overwinter in the deepest parts of the water. Many fish, like walleye and northern trout, will slow their heart rate, decreasing their need for energy and oxygen overall. With fall turn over, a process that mixes oxygen into the water, there will be plenty of oxygen to last throughout the winter. Like raccoons, these fish will not enter a true state of hibernation but wait for the warm spring air to return back to their usual underwater activities.
With ice separating ducks, herons and eagles from fish, a common source of their food, many birds have journeyed far and wide to warmer weather and open water. That being said, birds that can continue to find food often remain throughout the cold months of the year, with many of those being colorful and cheery songbirds. For as small as they are, they must get cold, right? Although their feathers protect them from the chilled air, they must turn to other strategies to truly survive the winter. If you look into nearby shrubs or trees, you may see small birds crowding together, or roosting, to share body heat. Even larger birds like crows will flock together to stay warm. Truly, birds of a feather flock together! Speaking of feathers, in addition to providing some protection from the elements, there are more that birds can do with their feathers to stay warm. Fluffing them up, for example, will create pockets of warm air trapped against their bodies. Some birds even have a gland to produce an oil that essentially waterproofs their feathers. Smaller birds, like chickadees, will lower their body temperature at night to conserve energy, entering that temporary torpor state.
All around the refuge, animals are doing what they can to make it until the spring, whether that be slowing their body processes or finding habitat for warmth. However, there are some animals, like foxes, that stay completely active during the cold months. Foxes have a thick fur coat - even on the soles of their feet to comfortably walk on the snow, like snow boots! On the prowl, they spend much of their short winter days hunting and foraging, looking for small rodents by using their sharp senses. Some may seek shelter in a burrow or den underground, but many will just sleep in the open, under the cozy, white blanket of snow.
Peaceful yet eerie, the refuge is quiet as many have journeyed down south in search for food or as animals are cozying up in their dens. The animals that remain active brave the cold Minnesota winter until the spring thaw. It’s apparent that animals who survive winters in our state put in a lot of effort, so what can we do to help them? Birds scout for high energy foods to stay warm. Suet, black-oil sunflower seeds and peanuts are great additions to your bird feeders! Native fruit-bearing trees or shrubs provide natural food and homes to animals. Roosting boxes or dead trees provide shelter for many, giving them a safe place to sleep or hibernate.
The refuge has many trails that are great for exploring and searching for the animals who stay here during the winter. When there is enough snow, check out snowshoes for free from our visitor centers or join a Nature Novice: Snowshoes program in January or February. Not only are they fun to try out, but they can also allow you to more easily go off trail and keep you warm! Another option is to view birds at the bird feeders from the coziness of the indoors and you can check out binoculars for free to help you take a closer look! Even if you’re a snowbird and migrate south during this season, we hope you can admire the strategies of animals staying active this winter and how we can learn from them by wearing warm layers, get moving and stay out of the wind.
