Hard Winter to Thin Deer Herd in U.P.
Deep snow and prolonged extreme cold is threatening deer in the Upper Peninsula and could kill tens of thousands. The harsh weather has prompted the Department of Natural Resources to take an earlier-thanusual look at the health of the herd. At the end of January, there tends to be two solid months of winter left in the U.P. If that turns out to be the case in 2014, this winter will also be abnormally long, a serious threat to deer survival because it prevents access to food on the ground for a longer period, leading to malnutrition and starvation, said wildlife biologist Kristie Sitar Friday, January 31.
This winter follows last year’s harsh winter. The deer harvest this fall was down 30%, and 15% on a threeyear average. Northern areas had three feet of snow on the ground in April 2013, prolonging the arrival of spring forage. This is too long for deer, Ms. Sitar told the DNR Eastern Upper Peninsula Citizen Advisory Council Thursday, January 23. Deer killed by hunters this fall generally had good body weight but poor antler development, she added.
Here, in the northern range of the white-tailed deer, the winter, not hunting pressure, is the factor that limits the size of the herd. In the north, the cold pushes the deer into heavy cover that holds the heat, and in these winter deer yards, to which the deer return each year, the available browse can be quickly exhausted. Malnutrition in pregnant does can lead to aborted or stillborn fawns, and some vegetation can be out of reach to yearlings, who are not as tall as an adult buck or doe. The congestion of deer can allow disease to spread more readily, and deep snow can reduce a deer’s odds against its lighter and more nimble predators.
Winters are tough on deer, and severe winters can be devastating. To help, the DNR allows some residents to feed deer on private property in the Eastern Upper Peninsula. Feeding guidelines prevent wellmeaning people from doing more harm than good, Ms. Sitar said. For instance, not all evergreens, such as spruce, are digestible by deer, and deer also need to build up bacteria that allows them to digest field crops, like hay, if this isn’t already in their diet. If someone doesn’t follow the feeding guidelines, it is possible that a deer could starve to death on a full stomach of food it cannot digest.
Owing to typically deep snow, residents in northern counties bordering Lake Superior maintain the right to feed deer by permit. This year the snowpack in Mackinac County and other areas bordering lakes Huron and Michigan have reached dangerous levels for deer, so residents here can also apply for feeding permits.
Deer congregating at feeding sites can increase the risk of disease, like the tuberculosis that is seen in lower Michigan, but disease is not the only danger presented by feeding deer. Natural bacteria in their stomachs help deer digest food, and the type of bacteria changes over the seasons. If whitetails have not been eating corn for months and suddenly gorge on it (as they will certainly do), they will die from the inability to digest the food, Ms. Sitar said.
A good winter for deer would be short and mild with low snow depths because cold and snow force deer to burn energy to survive. During a mild winter in the U.P., approximately 30,000 to 35,000 deer die. Moderately difficult winters see a death rate of about 70,000. Extremely harsh winters can hasten the death of 100,000 deer, a noticeable impact for sightseers and hunters.
Hard winters affect all deer, from the youngest and sickest to the strongest mature bucks. All are challenged by a snowpack less dangerous to predators like bobcats, wolves, and coyotes. Canines and felines can spread their toes, expanding the surface area of their paws to distribute weight. This helps them stay on top of the snow. The cloven hooves of deer, coupled with greater weight, leads them sink much more easily.
Northern deer create deeryards in the lush cedar swamps that hold their preferred forage. The yards often have microclimates slightly warmer than other areas, and the closed-conifer canopies block some snowfall from reaching the ground. Sometimes deeryards include patches of mixed hardwoods that allow them to brows on buds. Whitetails gather in these areas, creating safety in numbers, and developing complex, interwoven paths and runways that enable them to escape predators more easily.
The DNR will not cut cedar in deeryards to provide more food because it would amount to one-time feeding that would permanently reduce cover benefits. Once cedar trees are cut in deeryards, the herbivores will not let regenerating stands grow higher than the snowline.
Based in Newberry, Ms. Sitar spends time in the field during the winter doing work such as measuring snow depth. She frequents the Hulbert Deeryard, which borders private land where many residents are permitted to feed whitetails. Despite the supplemental feeding, she has seen signs of malnutrition. She recently caught sight of a young deer moving slowly, revealing the telltale “fuzzy face” that indicates trouble, she told The St. Ignace News.
Residents seeking permits to feed deer can contact the DNR in Newberry at (906) 293-5131 or Sault Ste. Marie at (906) 635-5281.