COLUMN: Brrr...it's cold outside

     As you shiver and shake in Iowa’s frigid winter weather, have you ever considered how Iowa’s native wildlife survives? Iowa’s native animals have many ways to survive an Iowa winter.

     Many of our songbirds and some insects, such as monarch butterflies, red admirals, and some dragonflies, sense the coming of winter and head south. This is called migration. You may have witnessed large flocks of migrating red-winged blackbirds, robins, or waterfowl. One day the robins are in your yard hopping around feasting on worms, the next they are gone, heading for their winter abodes. Even fish in our streams and lakes will make migrations heading to the deep water holes to congregate where they can access water depths with the right amount of oxygen.

     Those animals that don’t migrate must either hibernate or adapt to survive. Amphibians, reptiles, and some of our mammals will hibernate (sleep) for most of the winter. Some of these animals are deep hibernators spending almost the entire winter sleeping, others may be torpor or light hibernators awakening periodically to eat or move around. Snakes, lizards, frogs, toads and turtles slow down their body processes almost to a stop in very cold weather. Animals that are hibernating may survive off of body fat and can sleep for months, barely alive. They hide away for much of the winter in their dens, under stones, logs, in compost heaps, old mouse burrows, and even on the bottom of ponds – all sorts of places where they are hopefully safe from hungry predators.

     One of Iowa’s mammals that hibernate through the long winter is the thirteen-lined ground squirrel. They disappear in late fall and won’t pop back above ground until spring arrives spending most of the winter sleeping in their burrows, under the ground. Can you think of another mammal that hibernates?

     Many invertebrates hide themselves away too. Some adult insects hibernate; others die at the end of the summer but their eggs, larvae or pupae spend the winter hidden away, ready to continue their life cycle when spring arrives. Most female spiders, for example, die after laying eggs in the autumn, leaving their eggs in a round egg sac, tucked away inside a log, in a corner of a building, or under the leaves to hatch in the spring.

     In some animals, like gray tree frogs, glycerol, a natural antifreeze, helps prevent them from freezing. Many caterpillars (like the woolly bear), some butterflies (like the morning cloak), slugs, snails, queen wasps, bumblebees, and the ladybug all survive the winter in this way.

     Those animals that must stay active in the winter adapt. Their fur or feathers will aid in keeping them warm as they continue to seek food and shelter. Mammals will grow thick winter fur. Birds will fluff up their warm down feathers. Whitetail deer, coyotes, foxes, cottontail rabbits, bobcats, fox and gray squirrels, raccoons, chickadees, cardinals, blue jays, pheasants and a variety of other birds to name a few all depend on their warm fur and feathers.

     Habitat is also critical to the survival of all Iowa wildlife. For our mammals and birds, sheltered places, like windbreaks and waterways, to get out of the wind are extremely important. Iowa’s forests, prairie habitat, and field edges are essential to their survival.

     Even the blanket of snow we receive during the winter will help many animals survive. Snow acts like a blanket on the ground with many mammals, like voles, mice, shrew, and weasels using it as cover, warmth, and protection as they survive an Iowa winter.

     So as you sit in front of your warm wood stove or enjoy the blast of your furnace think how lucky you are and be thankful you’re not trying to survive outside with your wild neighbors.