who has witnessed large herds of elk and deer standing in deep snow on the outskirts of
town during winter has wondered where they find food, water, and shelter. They are capable
of traveling far distances and often migrate to satisfy some of their requirements, but
these may not enable them to overcome rapid changes in their environments such as the loss
of habitat from human development? Elk and deer have biological characteristics that
constrain them from being able to adapt rapidly, and competition for resources that are
all too often in short supply during winter may further constrain how they cope with
habitat loss. These constraints are not only difficult to identify, their interaction with
rapid changes across seasonal ranges, food availability, air temperature, and even
competition makes their effects elusive.
Knowledge of some basic principles of how elk and deer learn about seasonal ranges,
maintain energy and foraging requirements, and compete for resources may help us recognize
some biological constraints that may hinder their ability to adapt to environmental change
that we contribute to. An understanding of how they may compete for resources and how
habitat loss may accentuate the effects of competition is also important in recognizing
the plight of mule deer, for this species has been in decline since the 1950s.
Seasonal Ranges and Social Learning
Elk and deer live in large home ranges divided into summer and winter ranges. The winter
ranges of elk and deer are typically the lowest elevations in their home ranges. Because
these areas are low in elevation, they generally have shallow snow depths that enable elk
and deer to travel between sheltered forests and open foraging areas. Once they arrive in
a winter range, they are dependent on the food and shelter they can find there until the
snow melts in spring.
Young elk and deer learn migration routes to winter ranges by following their mothers and
other individuals. Consequently, these animals use the same migration routes and winter
ranges year after year, and over generations. Migration routes can therefore be viewed as
historical links to elk and deer herds from the past. They generally continue to follow
these same paths to familiar places because they learned that they provide food, shelter,
Deer have biological characteristics that require them to specialize in eating nutritious
browse like shrubs that are high in energy and easy to digest. Elk are generalists in that
they are adapted to eating nutritionally deficient grasses as well as nutritious shrubs.
Because elk are taller, they browse on tall shrubs that may be out of reach from deer.
Studies have also shown that although smaller herbivores like deer require less food,
their specialized diet requires that they spend more time selecting the more nutritious
food compared to the larger species like elk that can eat large mouthfuls of grass in a
short period of time. Being a generalist affords elk with the opportunity to eat grass as
well as the same foods as deer, and their higher reach and their larger size enables them
to outreach deer for food.
Elk and deer are always in search of food because it provides energy that helps them
regulate their body temperatures. They also depend on shelter to stay warm in winter. They
will travel to forested areas on south-facing slopes or river bottoms where trees provide
shelter from wind and warmer temperatures.
Elk and deer often live together throughout the year, but winter brings them in close
contact where they must share the same food and small area where snow is shallow. Recent
research indicates that they have the potential to compete for forage about one-third of
the time in spring and summer, but that it increases to over two-thirds during winter.
Elk are larger and generally more aggressive than deer, and can therefore directly
interfere with deer that are eating or searching for shelter in winter. Because elk have
access to more food, tolerate colder temperatures, use less energy traveling through snow,
and can walk through deeper snow, they also exploit more forage and shelter areas in the
winter range compared to deer. The competitive effects of elk can therefore reduce the
availability of food and shelter for deer, and therefore reduce their fitness in winter
ranges. Nonetheless, elk and deer have been coexisting in the same winter ranges for
thousands of years.
Our homes are often built in valleys and foothills, and roads are constructed along the
base of mountains. These areas are often the low-elevation areas that young elk and deer
learned from their mothers to travel to each winter to find food and shelter.
So, what does an elk or deer do when it needs to find food and shelter for the winter?
Their adaptations for energy balance, forage requirements, and locating seasonal ranges
requires them to migrate to low elevation areas. To reach the winter areas, they travel
along historical migration routes that they learned about from their parents. But, the
rapid development of winter range into homes and cities reduces the availability of food
and shelter, causing overcrowding, increased competition, and reduced abilities to reach
an energy balance. In this scenario, the fitness of mule deer is depressed because they
are the weaker competitor, and probably leads to them not surviving severe winter snows.
We need to recognize that elk and deer are in our yards and gardens because they are
trying to find food, water, and shelter in the only places that remain in their home
range. Providing a food crop and shelter between your home and the nearby hills may
represent the most environmentally friendly way to keep them away from your home while
enabling them to feed, maintain an energy balance, and continue to live through harsh
The Mule Deer Foundation: a non-profit conservation organization dedicated to stopping the
decline of this deer. http://188.8.131.52/entertainment/recreation/aoutdoors.shtml or
Hedrick, M. and B.L. Smith. 1995. Too many elk, too little habitat: current challenges in
wildlife management. Page 12 in Proceedings of the western states and provinces 1995 joint
deer and elk workshop. Idaho Department of Fish and Game, Sun Valley.
Henderson, R.E. and A. O'Herren. 1992. Winter ranges of elk and deer: victims of
uncontrolled subdivisions? Western Wildlands 18:20-25.