Northern winters are tough, but whitetails have the tools to survive.
As hunting season ends, the mercury plummets, snow piles up outside, and I hang up most of my gear for another year. But I still keep a few trail cameras out to keep tabs on the local deer herd and see which bucks made it through the season.
Perusing some post-season trail camera photos one day, I came across one that gave me pause. Most of the pictures showed fuzzy-faced does and fawns, their long winter coats giving them a chubby-cheeked appearance. The body shape on one, however, strongly suggested it was a buck that had shed its antlers, and closer inspection revealed what appeared to be bare spots on its head. What really caught my eye, however, was the absence of a front leg.
Somehow, this old warrior had managed to survive a grievous injury. Despite its obvious handicap, the buck appeared to be in reasonably good health. But winter’s onset would bring with it a set of much greater challenges, even for a healthy, four-legged deer. I doubted I would see many more photos of the three-legged buck.
Whitetails are extremely adaptable. Few other species exist across such a broad range of climates and habitats. From the jungles of Central America, through the Southwestern deserts, up the Rocky Mountains to the boreal forests of central Canada, each region has its share of challenges. But none rival the harsh winters at the northern limits of the whitetail’s range.
There, a winter day represents a life-and-death struggle. The challenges, any one of which is formidable, often work in concert, compounding their effects.
Food can be a limiting factor for northern deer. In spring, summer and fall, finding food is seldom a problem, even in relatively poor habitat. As fall turns to winter, greens die and wither, leaves fall, soft mast decays and hard mast is all but gobbled up. Food is at its least abundant and not very nutritious.
You can sometimes judge how hungry deer are by what they eat. They start out with coarse woody browse from preferred hardwood species like maple, dogwood and viburnum, as well as cedar. As winter progresses and whitetails need to fill their bellies, they become less selective, nibbling oak, beech and junipers.
If food is particularly scarce and they’re having a difficult time finding it, deer will eat almost anything. Toward the end of the worst winter I experienced, deer were feeding on white pine branches nearly as thick as my thumb. There was a record winter kill that year.
Other times, food is available but the deer can’t get to it, at least not without great effort. Most northern deer reach a point where they are operating at a calorie deficit, burning more calories than they consume.
The later in winter this happens, the better. And how long a deer survives depends partly on how much high-calorie food it consumed when it was still available — or how much fat it laid on before winter.
Snow compounds the issue, making it harder for deer to travel and find what little food remains. It also makes it more difficult for them to escape danger.
Deer face predators all year, but their impact becomes particularly important in winter. Predators play a vital ecological role, thinning out the sick and weak, helping to ensure that only the strongest individuals survive to pass on their genes to future generations. But it’s naive to think predators take only the sick and the week. They take whatever prey they can get with the least risk and energy expended. As snow piles up, the list of potential candidates increases.
Predators, particularly coyotes, are not driven solely by hunger. They’re driven by instinct, and researchers have documented what is called opportunity killing. When an opportunity presents itself, they will kill, even on a full stomach. In severe winters when deep snow impedes deer movement, coyotes will kill as many deer as they can, sometimes eating little or nothing from the carcasses. The same is true for wolves. The sick and the weak go first, but a healthy buck in his prime becomes easy prey when mired in several feet of snow.
Remember when you were a kid and your mother told you not to go outside without a coat because you’d catch a cold? Well, moms, science has proven that you don’t catch a cold from the cold; you catch it from someone else. Cold does increase stress and weaken the immune system, however, making it more difficult for us, or deer, to fight off the infections that already exist in our bodies.
Poor nutrition, increased exertion to obtain food and increased pressure from predators further increase stress, making deer even more vulnerable to disease.
Winter snows and limited food sources also concentrate deer into smaller areas, increasing the probability of disease transmission. This is one of several reasons why supplemental winter feeding is often not advisable.
While food is important, habitat is what determines the quantity and quality of available nutrition. While many hunters and writers use the words food and habitat interchangeably, they are not the same.
In addition to food, deer also need shelter. The closer each element is to the other, the more it benefits whitetails. Softwood cover helps decrease snow depth and breaks the wind, reducing the energy deer must spend to move, feed and endure the cold.
However, much of the North’s woodlands are privately owned, and owners are in the business of growing trees, not deer. Efforts to protect winter habitat through regulation have largely failed due to landowners’ arguments that it represents an unreasonable limitation of their rights.
Some state wildlife agencies have had moderate success with cooperative habitat agreements. Maintaining winter deer habitat can be accomplished through conservation rather than preservation, and timber can still be harvested. In fact, certain cutting prescriptions can actually enhance winter food and cover.
Despite all the factors working against them, deer still persist in the north woods. Natural selection is a strong force and has equipped them with the tools to survive.
Northern deer have longer limbs and bigger bodies to power through deep snow and outrun predators. Their winter coats grow long guard hairs to protect against bitter cold, and they learn where the best food and cover are. They pass that knowledge along to their offspring.
Winter yields to spring begrudgingly in the north woods, but it eventually passes. As days grow longer and the sun climbs higher in the sky, the snow line slowly recedes. You see it first at the bases of trees, then on south-facing slopes.
As the sun warms the soil, the first greens shoots poke through, providing a much needed source of protein for deer that made it through the long, harsh winter. Individuals have perished, but the species lives on.
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This article was published in the Winter 2014 edition of Buckmasters Whitetail Magazine. Subscribe today to have Buckmasters delivered to your home.