The Mule Deer Dilemma

Posted by Joe Bell on July 23, 2014 in Conservation
John hafner archive 03809 800x497 Photo: John Hafner
Ask any land or wildlife manager on the scene, and they’ll say the biggest reason for low muley numbers is human sprawl. Growing human populations cause more land fragmentation as we build more homes and roads, all of which increasingly stress these animals’ environments.

I’ve bowhunted mule deer all over Western landscapes the past 10 years, traveling across several mountain states, including my own, Arizona, as well as Nevada, Colorado, Wyoming and New Mexico. Based on these on-the-ground assessments, as well as verbal and written assessments from wildlife managers, I’m baffled by the muley’s dwindling numbers.

Strong deer numbers prevailed in some regions I hunted, with plenty of good bucks holding in pockets. In other areas, the population was way down. A disease outbreak or vast winter kill were the primary suspects.

Low moisture is also an ongoing issue, as many Western eco-regions have received little rainfall and accumulated shallow snow-packs at high elevations. This results in less water flow for vital tributaries and less moisture for growing vegetation.

But is drought the main cause of the mule deer’s declines? Although it’s a contributing factor, it’s not the entire problem, according to many experts. They point to several other factors, and put habitat losses atop the heap.

The following summarizes what the experts are discussing while reviewing recent data and population counts to better understand the probable causes for shrinking mule deer populations.

No Land, No Deer

Ask any land or wildlife manager on the scene, and they’ll say the biggest reason for low muley numbers is human sprawl. Growing human populations cause more land fragmentation as we build more homes and roads, all of which increasingly stress these animals’ environments.

This stress worsens because of these factors:

  • continual losses of wintering and summering grounds,
  • disturbances to natural travel patterns (from bed to feed to water, or from summer range to winter range),
  • and loss of life as more roads increase deer-car collisions.

Urban sprawl is not expected to ease or cease, either. In fact, it could double in about 30 years. This troubles wildlife managers because it reduces their options for improving habitats to support mule deer.

“Mule Deer: Changing Landscapes, Changing Perspectives,” is a publication from the Mule Deer Working Group of the Western Association of Fish and Wildlife Agencies. The report seeks to educate the public about critical mule deer wintering and migration areas. And to reduce deer-car collision, the report suggests building travel tunnels or overpasses along busy roadways, and planting specific vegetation along passageways to deter wildlife from feeding or staging along roadways.

Oil, gas and mining exploration is also booming in the West and creating jobs, which is good. But the Mule Deer Working Group notes that increased oil/gas production could create more problems in mule-deer range, including more habitat fragmentation, ground-water contamination and above-ground disposal. Some experts even view mining sites as tremendously detrimental because most are in remote regions that directly affect muley habitat and migration routes.

Call for Better Nutrition

Habitat problems can also hamper mule deer health. Those concerns start with the mule deer’s stomach. Muleys are ruminants with special digestive systems that can only digest certain foods efficiently. Although elk can forage on wide varieties of grasses and plant communities, mule deer require specific shrubs (brush) and forbs (weeds and flowering plants), especially those in early growth stages.

Therefore, fire provides major help for mule deer. The more small fires that burn older-stage forests –without violently burning hundreds of thousands of acres at once – the better the habitat becomes for deer nutrition and growth. Therefore, recent increases in forest fires will likely enhance the mule deer’s future.

In contrast, invasive plant species are increasing and slowly replacing many native plants and grass communities. This is a great concern because mule deer do not easily digest these plants.

Cheatgrass is the top offender in most areas, according to the Mule Deer Working Group. These plants infiltrate areas by germinating before native plants, sucking up ground moisture, setting roots, and quickly dehydrating fresh-growing natives to death.

This might seem a small issue, but entire mountainsides of lush perennials (prime deer feed) can be displaced by unpalatable invasive weeds in just a few years. This leads to less forage for muleys, greater stress, and reduced fawn survival for these cherished ungulates.

Predator Impacts

Meanwhile, habitat degradation could leave muleys more vulnerable to predators like coyotes, mountain lions and wolves. Much study and analysis is needed to determine these predators’ true impacts on deer populations, but it’s difficult for ungulate populations to grow if their habitat provides little food or cover. Such conditions leave deer, especially fawns, more vulnerable to predation.

Elk and Cattle Competition

Some hunters believe elk play a role in dwindling muley numbers, but that’s difficult to quantify. After all, deer and elk have historically shared much the same range without drastic population fluctuations, according to wildlife experts.

Granted, elk often use the same food sources as deer, but in other cases food preferences differ by season because of each species’ unique digestive systems. In addition, elk are more robust than muleys and less affected by extreme winters because they can move through deep snow more efficiently and reach higher into vegetation to eat. Even so, higher elk densities don’t necessarily come at the muley’s expense. Elk are just more capable of living off the current habitat.

“A broad statement that elk are responsible for mule deer declines is certainly not accurate,” states a fact sheet from the Mule Deer Working Group. “Several important mule deer populations have declined even without elk being present. Other deer populations have grown and responded well in conjunction with growing elk herds.”

Many experts, however, believe overabundant cattle in some areas cause direct competition for mule deer. Too many cows spending too much time in one area can damage habitat and deprive deer of much-needed food. When controlled properly, however, the right amount of cattle feeding for the right amount of time on these habitats can benefit deer. These large herbivores often eat plants deer don’t favor, and by disturbing the soils with their hoofs, cattle can encourage the growth of shrubs deer prefer.

In one high-country area I often hunt in Nevada, I see lots of cattle in valleys and on ridges used by deer and elk. Despite the cattle’s constant presence, I haven’t seen negative shifts in deer numbers or sightings in the four hunting trips I’ve made to this area the past decade.

Calculating Deer Numbers

Wildlife agencies in Western states use different methods to manage game herds and allocate hunting tags. Some states use aircraft to survey deer populations, but others do not. Some states survey entire deer units, while others focus on representative areas within units to estimate deer numbers. Agencies usually combine this information with harvest trends to establish hunting/management plans. All these methods have worked in the past, but wildlife managers keep pushing for more exact science in hopes of creating a standardized system all states can use to improve deer numbers. For mule deer to come back strong, their management must become a Western issue, not a state-specific issue.

When considering today’s hunter-harvest trends and statistics, I feel concerned. Today’s hunting tackle is more powerful, accurate and effective than ever. We have better trucks, better optics, laser rangefinders, trail cameras and so on. These tools help make us more effective and successful, despite fewer muleys. Or is that just one man’s perceptions? Game managers will likely evaluate these concerns as we move forward .

Is There Hope?

A few years ago, a buddy and I backpacked into remote wilderness country in southwestern Colorado. We enjoyed an incredible hunt and saw staggering numbers of mature bucks. After multiple failed stalks, we arrowed two trophy bucks.

Two seasons later, we returned to the same basin, but saw only a handful of does, a few small bucks, and one nice 4-by-4. We hiked from one side of the massive wilderness area to the next, and even hiked out, drove around the unit, then hiked in from another location. Deer numbers were low everywhere.

“We had a hot summer up high,” a Colorado wildlife official told us over the satellite phone. “The grass was scorched, and the deer moved to lower elevations. You’ll find them in the trees.” Unfortunately, we saw the same poor results when hunting lower ground.

While hiking out of the area, we ran into two old-timers hunting firewood and grouse. “We haven’t seen much for deer the last couple seasons,” they said. “We’d say 70 percent of the population was wiped out by that winter four years ago.”

Even so, I returned for the final five days of the season, drove to a different mountain range across the highway, and saw several bucks before filling my tag. I even missed a 190-class monster.

If I’ve learned anything about mule deer in 20-plus years of hunting, it’s that they know how to find better living places, and hold to these pockets of vegetation. They can also produce more offspring than elk, given good habitat.

So, I remain optimistic and encouraged about their future. After all, the West’s relentless forest fires of recent years are creating new-growth habitat, and Wildlife experts are well aware of multiple trouble spots in managing muleys. A unified group of officials are dedicated to address those concerns.

To learn more about mule deer conservation, and to read quality publications on the subject, visit

Also, by joining the Mule Deer Foundation, you can help ensure the success and protection of this species and its habitats. Annual membership is only $35. Please visit

Hunter Photo: John Hafner; Land Photos: Joe Bell; Deer Photo: Oborseth - Own work - Creative Commons