Mule Deer Watch: Winter’s Rage on Winter Range

Mule Deer Watch

Winters Rage on Winter Range
Michael Burrell

It appears that snow-skiers and mule deer hunters will be talking about the winter of 2007-08 for years to come. As I write this, sportsmen and wildlife biologists alike are crossing their fingers that warmer weather is on its way while mule deer struggle to survive amidst extreme snow depths, temperatures well below zero, and a layer of hard-crusted snow that makes foraging for food extremely difficult. Within my warm home beside a log fire and a nice beverage, I search the internet for tonight’s low temperatures across the West: Kemmerer, Wyoming -18° F; Gunnison, Colorado -20° F; Burns, Oregon -12° F; Vernal, Utah -10°. Someone forgot to tell the western United States that we’re in a global warming emergency. Immense snow storms have been the norm for weeks and the weather forecast isn’t expecting a break anytime soon. By the time you read this, we’ll have a better idea on how the deer fared this winter season.

A heavy winter, such as this one, brings back the horror of the devastating 1992-93 winter from which mule deer populations across the West still haven’t recovered. I discovered the effects of hard winters at a young age. It was a cold January morning and my dad and I were walking alongside a lake to do some perch fishing through the ice. To my right in the deep snow, a brown patch of fur caught my eye. It was a doe stumbling to get up from her bed. At first, I was thrilled to see a deer so close. My reaction, like most young kids, was to get as close as I could before she spooked. She dropped back to her knees and lowered her heavy head, surrendering to the elements. I knelt down next to her and patted her matted winter coat. Her bones poked against her skin like tent poles and her breathing was heavy like she had run a mile, but she hadn’t. I can’t recall if any perch were caught, but I still remember my dad’s consoling words on winter kill being a natural event.

It is painful to see sportsmen and wildlife agencies contribute so much effort in sweat and dollars to recover mule deer populations via enhancing habitat, managing stronger buck/doe ratios, predator control, and so forth. And then, in a single rogue winter, Mother Nature jogs our memories of who’s really in charge in this thin-skinned environment.

Whether in form of snowflakes or raindrops, precipitation can be a curse or a blessing for mule deer - it all depends on the amount and the timing. Normally, higher levels of precipitation improve production of nutrient-rich deciduous shrubs, which mule deer need to maintain good health and maximum antler growth. Too much precipitation, in the form of deep snow, can cover the deer’s groceries and they must then dig for food or travel in search of greener pastures. Such effort robs them of precious energy.

Mule deer adjust their feeding patterns as snow deepens. Snow depths exceeding eighteen inches essentially push deer out in search of less snow. One study in Colorado showed that in two of three winters, over ninety-percent of winter range was excluded from deer use because of snow depth. When snow is deep, deer generally feed from noon into the late afternoon when the sun warms up the snow and makes it softer and easier to paw for forage. They tend to target areas where snow isn’t as deep such as south-facing slopes, wind-blown ridges, and under trees.

In contrast, years with low levels of precipitation reduce forage availability and quality and force deer to eat older plants with less nutritional value. Deer, therefore, go into winter in poorer condition. Much of the West has experienced drier than normal conditions in the past few years. The cumulative effect of these drought years has left winter-range forage in dismal shape. This fact, coupled with this winter’s large amounts of snow and extreme cold temperatures, is the formula for a catastrophic deer winter kill.

It’s a feeling of utter powerlessness to watch mule deer experience a heavy winter. Should humans intervene and help starving mule deer or allow “nature” to take its course? Some believe humans shouldn’t interfere with the “natural cycle” and that extreme weather is nature’s way of controlling wildlife. This cycle has been going on for eons – only the strong survive. However, there is a setback to this way of thinking for the reason that humans have already interfered with mule deer and the so-called natural cycle. Let me explain.

Today’s mule deer experience more unnatural obstacles than in any other time in their history. Taking into account that human-influenced habitat changes should be credited as a major cause for the creation of most of the best mule deer habitats in the early 20th century; the drive for more development on mule deer habitats today far exceeds historical demands for growth and expansion. As human populations increase, we give way to housing growth, oil and gas development, bigger highways, faster speed limits, higher fences, and man-made reservoirs rather than mule deer migration routes and winter range. Thus, the natural world is not able to overcome the effects of man’s “progress” and the mule deer lose, especially during a harsh winter.

What can be done to help mule deer during a hard winter? Biologists believe good winter range is the biggest factor limiting mule deer populations; therefore, the clear answer is for humans to improve and protect the existing critical winter ranges. Today, mule deer enthusiasts have a better understanding on just how important winter range truly is. Countless projects, funded by sportsman’s groups, are helping to enhance critical habitat.

Sadly, huge sections of winter range have already been lost to human development. Developed winter ranges force deer into more susceptible areas with higher risk for winter mortality; either into the developed area, which brings upon its own risks or on a more non-traditional wintering area, which is usually uphill with higher snow levels.

Most state wildlife agencies recognize that supplemental winter feeding is a tool to be used under certain circumstances, such as to promote public safety by drawing deer away from highways and urban areas, control big game damage in agricultural areas, and to assist deer that have recently lost winter range to development or wildfire.

This winter, the Colorado Division of Wildlife launched a massive feeding program in areas that were hit hard by massive snowstorms including the Gunnison Basin, one of Colorado’s popular trophy muley destinations. A total of $2 million, which came from sportsmen’s license fees, was authorized to pay for the emergency aid along with overwhelming financial support from sportsmen donations all across this great nation. “We thought if we didn’t feed, we’d hit that trigger where more than thirty-percent of the adult females would die this winter, and it’s very difficult to recover a deer herd at that point,” said Tyler Baskfield of the CDOW. Without supplemental feeding, mule deer herds in affected areas may experience a ninety-percent mortality rate for fawns and thirty to forty-percent mortality for adults, which would compel a hunting reduction as well as millions and millions of dollars in economic loss to local Colorado communities.

Although supplemental feeding may seem like a no-brainer to improve the survival of deer that may otherwise succumb to starvation, there is evidence that supplemental feeding, if done incorrectly, may do more harm than good. A common mistake when supplemental feeding is the use of the wrong feed. A mule deer’s stomachs, all four of them, are very efficient at getting large amounts of nutrients from their forage. Each stomach plays a critical role in breaking down forbs into smaller pieces and, in due course, the nutrients absorb through the intestines. The microbes (bacteria, fungi, and protists) that provide nutrients that the deer can digest in a deer’s stomachs are specific to the type of food a mule deer eats. For example, some microbes break down woody plants such as sagebrush; other microbes break down forbs like grass. If a mule deer has been steadily browsing on woody plants on the winter range and is suddenly introduced to a first-class dose of hay, the woody plant microbes that have done a great job of breaking down nutrients have no time to adjust to grass and forbs and the deer will starve to death with a stomach full of hay. Wildlife agencies use a specialized pellet developed by researchers to feed the deer. The pellets are easy for deer to digest and stay on top of the snow so that they are readily accessible.

By providing the proper feed and only in times of critical stress, supplemental feeding does work. Chris Peterson, a student at Utah State University, has devoted her research to the effects of supplemental feeding on mule deer in northern Utah. Years of research show that deer that were fed experienced better health, reproduction rates, and survival. On the negative side, it was noted that deer that were fed stayed on the winter range longer looking for a hand-out. This behavior could negatively impact the winter range by decreasing forage availability for the upcoming winter.

Get involved and help support those non-profit groups who contribute time and money to mule deer management. This year, I couldn’t be more proud of the sportsmen that have stepped up to the plate by donating their own money and free time to help haul feed to hungry mule deer. It attests to the rest of the community which crowd is truly concerned about mule deer.

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