By Dana R. Rogers
There aren’t many times during the year in which deer experience a low-stress lifestyle. As winter covers the Dakotas, deer herds are in a nutritional decline.
In many northern areas, it’s extremely difficult for deer to consume the 6 pounds of food intake their bodies require each day once winter grips the landscape. As a result, deer in northern climates can often lose as much as 25 percent of their body mass by the time spring arrives and and provides plentiful browse.
While spring, summer and fall present unique challenges for deer, winter is by far the hardest period of year for them. The elements are harsh and can be unforgiving, and the numerous challenges that accompany extreme temperatures, snow and ice can wage a physical battle on the condition of the herd.
Fortunately, deer are built to endure and thrive, and they have the ability to overcome the most adverse circumstances during any given season.
Physiological Changes and Needs
Deer have the proper physiology to survive during winter, but they need food and cover to sustain it. During harsh winters, deer mortality can be devastating if they lack food and cover.
The determining factor if a deer will survive the winter or how it will fare by the end of the season is its physical condition and if its nutritional needs were met during the fall. Studies suggest that it’s important to consider the timing of winter and spring in any given year. An early winter combined with a later spring, for instance, can add an extreme amount of additional stress that is tough for deer to overcome.
Healthy deer typically go into winter with fat reserves that provide an indirect source of energy when a deer’s habitat offers little to no food or forage. Deer need to conserve energy during winter, because if they burn more calories than they consume for a long period, death will soon follow. During stressful periods like this, a physiological change occurs that results in a decreased metabolic rate.
With little nutritious forage and browse available, deer undergo physiological changes throughout the winter. It is their internal survival mechanisms that are key to surviving the winter. Finding sources of carbohydrates, protein and essential nutrients can be really difficult, resulting in a lower caloric intake.
The only way deer can survive especially severe winters when food sources are limited is to conserve as much energy as possible to ensure their fat reserves aren’t depleted by winter’s end. The only way for them to accomplish this is to naturally and gradually decrease their activity levels.
Smaller-bodied animals lose body heat more quickly. Large body size conserves energy better because of a lower surface-to-mass ratio. This is why it’s vital that deer take advantage of the energy- and carbohydrate-rich foods when they’re available. This could mean the difference between surviving the winter and not.
Keep in mind that by the end of the rut a deer’s fat reserves have already been dramatically depleted. By the time the rut is winding down, dominant breeding bucks are often pretty gaunt, and, to make matters worse, they don’t really have a great recovery opportunity up north. By the time the rut ends, winter has already arrived and food is likely scarce.
For these reasons, bucks often head into winter depleted and stressed from the rigors of the rut, while does are growing fawns and perhaps even still nursing their previous offspring. Fawns are also especially vulnerable during the winter if their mother didn’t receive adequate nutrition while pregnant or if the fawn had a later birthdate.
Studies show that a deer’s lowest metabolic rate is during the month of February. Once does enter the last half of the gestation period, when fetal growth increases rapidly, the metabolic energy significantly increases. If does can’t get an adequate amount of nutrition in their food sources, they can become so run down they actually absorb their unborn fawn.
Externally, the job of a deer’s winter coat is to insulate against the cold. A deer’s winter coat is darker and actually absorbs solar energy. The rough, hollow guard hairs of their winter coat are longer and provide protection and insulation by trapping air, but it’s the finer hair underneath that really affords the greatest insulation value. As a result, their well-designed coat not only absorbs heat, but it also insulates against heat loss.
In addition to harsh winters, deer also face threats from predators. From hunters to coyotes to even mountain lions in some areas, predators can cause a lot of stress on deer during the winter. Hunters can really help deer and other wildlife by eliminating predators, and hunting and trapping predators such as coyotes is a great wintertime management effort to keep a deer herd’s stress at a minimum.
I’m certainly not a great coyote hunter or trapper, but I make a concerted effort at predator control, especially during the winter. I also try to help by encouraging friends and neighbors to do the same.
Lately, I’ve started to advocate for more predator control by providing neighbors with traps and even buying shells for every coyote they take. Another great option is participating in some of the many coyote-calling contests or predator roundups that often happen during winter months.
Hunters can also help deer during the fall by providing additional habitat and food sources so deer can enter the winter season as healthy as possible. In addition to providing fat reserves, additional food sources also help sustain deer and recoup from rut stress.
I am fortunate to have the ability to plan several acres of food plots for our local deer herd. Corn is low in protein, but high in carbohydrates, and carbs are what deer need to generate warmth during frigid conditions. Corn should be a part of your food process, but I also like to provide brassicas such as radishes and turnips.
While corn and brassicas are great, my favorite food plot is soybeans. I highly suggest all three for a perfect combination of late-season attraction and wintertime nutrition.
If you don’t have the ability to provide food plots, you can always put out shelled corn or alfalfa, where and when it’s legal to do so. However, if you choose that route make sure you don’t stop, or you could cause more harm than good. Providing food sources is wonderful, but remember that keeping it close to abundant cover and thermal habitat is absolutely critical.
Providing habitat that has everything deer need to survive winter can truly make a difference. These spots should be protected from the elements and have thermal cover consisting of native grasses or mature conifers next to food sources.
Cedar groves, for example, make great winter deer yards. They provide critical thermal cover, as their dark-green foliage absorbs heat from the sun, and they also provide protection from harsh winds.
Good wintering areas like these offer escape cover, too, where deer can flee or remain hidden from predators. So, to help the herd in your hunting area, consider planting cedars or establishing a few acres of warm-season grasses this year.
Deer will search out wintering areas where they can conserve energy. They begin eating less and moving less. Their feeding patterns seem to rely heavily on temperature and weather patterns.
A prominent wildlife habitat manager I know estimates that deer movement starts to slow down when temps dip to around 15 degrees.
If you get below-zero temperatures or heavy snow and wind for extended periods, you can even see deer that stay bedded-up for several days. Movement can be dramatic just before or just after periods of heavy snow or blizzards, as deer need to fill their stomachs and gain energy to burn.
When deer needlessly have to expend large amounts of energy it really hurts their survival chances, so give them space and keep their stress low by reducing predators, providing food sources and adequate cover. Also, do your best to stay away during late winter, or you’ll risk causing unnecessary disturbance and stress.
Impact on Farmers and Ranchers
Farmers grow abundant food sources for deer during the spring, summer and fall, but once the crops are harvested and covered in snow, it’s often a vast wasteland out there. As a result, what often happens during severe winter weather are seasonal relocations and sometimes migrations to winter yarding areas. In the Dakotas, more times than not, this means right next to or into a farmer or rancher’s livestock feed stores.
Each winter varies depending on its severity, but this crucial time can be extremely taxing on deer herds as their primary focus becomes all about surviving by exerting as little energy as possible. However, their survival instincts will often put them in direct conflict with producers.
Private landowners don’t own the deer, but they sure as heck feed the majority of them. Let’s help do our part in managing our resources and keeping tolerance levels manageable for producers.
One way we can help do our part is by taking excess antlerless deer when the opportunity arises. By helping out a farmer that is inundated with deer on their corn or hay pile, you may make a new friend and contact for a future full-time hunting location. At the time of this writing, most deer seasons are closed, but there are often depredation options available if you look into them.
The elements of food, water and cover are necessary to sustain wildlife. By providing food, bolstering wintertime cover, and managing predators and winter stress, we can help our deer resources get through this difficult time.
Our home property holds more deer through the winter than any other time. The reasons are simple, and they’ll always be the same — food, water, cover and security. Even if you don’t own land, knowing what deer are going through and helping out when and where you can is within every hunter’s reach.
Please always remember when you are afield to respect the land, respect the landowner and respect the wildlife.
About the Author: Dana R. Rogers grew up in central South Dakota before serving in the U.S. Air Force. He now lives in the Black Hills and can be reached with questions or comments at [email protected]