Seasons don’t fear the Reaper
Nor do the wind, the sun, or the rain

–Blue Oyster Cult

It’s hard for post-industrial humans to take winter seriously. We spend more money to heat our homes. We complain on the way to the car. Sometimes we bundle up and go outside. While it’s not enough for most of us to notice, the human death rate does still rise in the winter. That is largely due to disease among the elderly.

Our ancestors didn’t have any trouble understanding how serious winter is. It’s true that for a very long time our holidays and festivals have been during the late fall and winter. In agrarian economies, there’s a lot less work to do in the winter and what work that could be done is harder to do. So it was a perfect time for celebration, if for no other reason to distract from hardship. The fall harvest creates a surplus that can be skimmed off for a feast. The quality of the harvest didn’t only fuel holiday feasts, however, but rather gave everyone a good idea of who would still be alive in the spring. In those times, most death would occur during the winter. The worse the winter and less prepared the community, the more death would occur.

The order of death isn’t that different in humans than it is in other mammals and is mostly related to physical strength and dexterity. First the sick, disabled, and injured perish. These are followed by the very young and the very old. Next the older children die followed by their mothers and finally their fathers. That’s because the stronger you are the more ability you have to fight the cold and the more resources your body has to fight off starvation. You also have the ability to strike off on your own and find your own resources, if necessary. In the end, strength and dexterity mean you can hoard and take resources by force. In humans, no doubt, chivalry, sacrifice, and parental instinct changed the order of death often. However, such a thing would typically fail in its purpose, since children would rarely survive without their parents and women would generally not survive without the men.

For the wildlife of Michigan, the realities of winter are still with us. Winter is a season of cascading effects, all initiated by our tilting away from the sun. This makes sunlight less direct, and reduces the time of daylight. Shorter days impact diurnal animals, like humans, that are active during the day. Shorter days also reduce the amount of energy available for photosynthesis, which is how plants feed themselves. The lack of energy from sunlight also causes temperatures to plummet. Cold blooded animals can no longer maintain their metabolism and grow dormant or die. Warm blooded animals expend more and more energy to maintain their body heat at a time when less and less energy is available.

The next effect of winter relates to the freezing point of water. Here in Michigan, high temperatures will be below freezing on most days. Lakes will skim over with ice, melt, skim again, and freeze solid. The ice creates a barrier for animals entering and exiting the water. It will block oxygen from getting to the fish and other creatures in the water. On land, the water in plants will freeze. Plants rely on water to transport nutrients. When the water freezes it cannot transport nutrients and the plants’ cells can be damaged. Some plants completely die. Others fade away to their roots. Trees go mostly dormant. The failure of activity in plants removes most of the food for animals from the landscape.

Then, precipitation doesn’t melt causing snow to build up on the ground. Lakes are plummeted into months of darkness below the layers of ice and snow. Photosynthesis in water plants ends in the lakes and waterways. Any remaining food on the forest floors, meadows, and fields are covered up first with snow and then by layers of ice hard for animals to paw through. The snow makes it difficult to move from place to place, unless you can run on top of it.

As temperatures drop and food becomes less available, most animals move a lot less to conserve energy. Animals will feed in cases where the energy gained exceeds what they expend while feeding, and these opportunities grow more rare as winter progresses. Otherwise, they hide in areas where they are shielded from the wind and the vegetation absorbs and holds energy from the sun, such as conifer forests. Conifer forests also reduce the depth of snow, I believe because the snow collects on the branches and melts in the sunlight even on below freezing days. Despite the shade under pine trees, these are the first places free of snow every spring.

Other animals find even more clever places to hide. While spreading some used animal bedding last spring, I found a rabbit nest in the straw. This rabbit burrowed in and was not only insulated by the snow and straw, but the decomposing straw and manure are a natural heat source. I’m guessing that rabbit was one of the warmest animals in the area last winter, almost as warm as me in my cabin. I’ve written before how ruffed grouse will roost under powdery snow. Sometimes when you are stomping through the snow, suddenly a bird the size of a small chicken will pop out at your feet and thunder away through the trees. I’ve wondered how many heart patients have breathed their last as a surprise grouse flushing from the snow inspires a heart attack.

Other animals like bears and beaver prepare shelters for themselves. Beavers live in lodges with their family and enjoy above freezing temperatures all winter as their body heat is trapped by layers of sticks, mud, and snow. Bears insulate their beds with vegetation they pull in from the area. Sometimes they excavate holes in the ground, sometimes they find natural shelters like under the root balls of fallen trees, and, in rare cases, they just hibernate on the ground. A number of unlucky homeowners have found bears hibernating under their deck or in their cellar, typically after tearing the insulation and materials out of their home to make their nest.

I spent time visiting family this January in the southern part of Michigan where temperatures are warmer and snow accumulation considerably less than where I currently live. I was surprised to see many of the same movement patterns as up north, though to a slightly lesser degree. Songbirds were harder to see, squirrels and rabbits rarer, and deer tracks far less numerous. Animals will feed in secluded areas near their sleeping areas. Behind my family’s home is a crop field not visible from any road due to being concealed by woods and tree lines. This was a very popular spot for deer to paw through the snow and find discarded food. Sometimes I would walk back here and jump several dozen deer at a time.

In addition to moving less, animals move more intentionally in the winter. For instance, during most of the year, deer tracks will move from point A to point B in a very wandering pattern, often not repeating themselves exactly from day to day. These deer are looking for vary their diet with various morsels of food they find along the way. However, during winter culinary surprises are rare and these same deer will move in a straight path directly to a priority feeding area. I was walking through a field in public land next to a lake and I was surprised to see few tracks near the tree lines and shoreline where I expected them to be. In farmland, deer have far less cover than in the dense forest and it’s relatively easier for hunters to ambush them on likely travel paths. I saw evidence of this as I spotted several tree stands still remaining from hunting season. The deer, however, had different plans. They had found a large hill in the field and, just over the hill out of sight of the tree stands they crossed cutting a straight 12 inch wide trail through the snow used by many deer. Few deer wandered from this narrow trail except when it intersected a tree line, in which case a few deer couldn’t help themselves but meander about and browse from the twigs of young trees.

While tracks are easy to see in the snow, they can be hard to identify especially when the snow is powdery. This is especially important because due to changes in movement patterns in winter, tracks may not belong to who you expect. During the summer, most large animal tracks are deer tracks as deer are far more numerous than predators such as wolves, foxes, coyote, and bobcat. However, during the winter deer move far less while predators move at much more similar levels to the rest of the year. That’s because the food source for predators is still abundant and, in fact, since prey is moving around less they need to go looking for it. Also, in many cases, late winter is mating season for predators. This January, I set up some trail cameras to observe deer movement. When I picked up one of the cameras I saw some tracks in the snow and assumed they were deer. Instead, I had pictures of a fox and a coyote and the deer weren’t even using the same trail they did in the fall. Often, individual tracks belong to a predator, though these could also belong to bucks or orphaned deer. If you look carefully at tracks in the snow you will see the outline of hooves in some of the tracks. Even in very powdery snow, you can often see the imprint of dewclaws at the rear of the track. If you follow the tracks you will see deer feces which is a giveaway and deer urine which turns red in the snow due to plant proteins. Predators don’t eat a lot of plants.

Many animals fight the cold by moving during warmer times of the day. Some animals like song birds, grouse, and squirrels are active during the day anyways while animals like owls and raccoons are nocturnal and active at night. However, crepuscular animals, animals naturally active in early mornings and late evenings, are very adaptable and can tailor their activity to weather and predators. Examples of crepuscular animals include deer, rabbits, bears, coyotes, and foxes. The change in the movement of deer is especially evident as December fades into January. As hunters leave the woods and temperatures fall they no longer avoid the daylight hours often waking with dawn just like we do and moving on and off through the day. Around New Years, I spotted several in the middle of the day walking directly down forest service roads to take advantage of the shallower snow.

Not only does snow block animals from reaching food, it also impedes their movement. I didn’t fully appreciate this until living in Northern Michigan. Once snow exceeds knee deep, walking can really be a struggle. However, it gets easier if you can use your own trail pressing down the snow and clearing it out of the way for when you return or use the same trail again. The other way of traveling in the snow is to walk on top of it. This can be done with snowshoes. During December we had a lot more snow than usual but it also melted and froze a few times. In many areas I was able to walk on top of the crusted snow without snowshoes, thanks to my large human feet. It’s just annoying every five steps when your foot crunches and punches through sometimes scraping your shins on the upper crust.

Different animals have similar methods to me for traveling through the snow. Large animals repeatedly use the same paths to clear trails and make travel a lot easier. Small animals might be able to walk on the snow. But this is hard to do when the snow is cold and powdery. During late November and December, we saw a lot of early powdery snow. I saw a huge drop off in sightings and tracks of rabbits, hares, squirrels, and grouse. For example, grouse typically behave like chickens in the morning. They will fly from their roost and walk all over the place looking for food. However, when there is snow on the ground impeding their movements and covering food, they will mostly stay in one place and fly into the trees to feed. Then, after a few warm days the top of the snow thawed and refroze. I started seeing a lot more small animals and a lot more tracks as this crust of snow could support their weight. The drawback is the crusted snow makes it even harder to reach food, and movement was still much less than before the snow.

In a previous blog post about understanding wild animals, I wrote that you can understand animals by studying three things: how they reproduce, how they avoid predators, and how they survive winter. Winter has a profound impact on an animal explaining everything from their bodies to their behavior. There are trade-offs to everything an animal is and everything an animal does. A larger animal has greater strength to travel through deep snow, while a smaller animal uses less calories and might be able to run on top of the snow. Each animal has it’s own strategy. For instance, I wrote in my fall post how squirrel species will become smaller the more desolate their landscape. Large fox squirrels inhabit boundary areas with the largest variety of food, medium grey squirrels inhabit contiguous hardwood forests, while tiny pine squirrels survive off of pine nuts in comparatively sterile pine forests. This is because larger squirrels depend on plentiful mast crops. Conversely, deer, rabbits, and hares often grow stronger and larger the more difficult their environment. Hares live in the coldest most forested areas of Michigan with the deepest snowfall and are larger than cottontail rabbits. Their size allows them to survive the snow and winters and their large rear feet help them to float their large bodies on top of the snow.

I’ve written a lot of words in this post explaining Michigan’s winter, the factual basis behind it, how animals and plants react to it, and my personal observations. No doubt, few humans would survive more than a couple days in the wilds of Michigan during winter. Many wouldn’t survive a few hours. I personally have no interest in becoming the test case. Yet millions of Michigan’s wildlife will survive minute by minute, hour by hour, day by day, week by week, and month by month. They will emerge from winter, grieve the family and companions they have lost, and grow stronger in the coming year. While our winter started early with a cold December, we seem to have received the respite of a warm February. But winter still has plenty left to give us.

Yet, while a simple focus on death and hardship may be an accurate description of what happens in winter, it wouldn’t be an accurate depiction of why that must be. For wildlife, the next weeks will be the final battle in the war that is one more year, a war that began last spring. Most of the things the plants and animals of Michigan have done over the last year have been to prepare them for this. This is their championship game, their final exam, their great race, their final lap, their moment of truth. Much more, everything in their biology is a gift carefully designed over millions of years that has given them every advantage they can have to make it across the finish line. Therefore, there is more at stake then their lives alone, or even survival in general, but rather the future flourishing of their species.