BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Odocoileus hemionus | Mule Deer 



TIMING OF MAJOR LIFE HISTORY EVENTS : 
Mating Season - usually begins in November and continues through
                December in the north; may begin in December and
                continue through January in warmer climates; can
                begin in September for black-tailed deer 
Gestation - about 6 or 7 months 
Birthing Season - usually begins in June and can continue into August;
                  may begin in April for black-tailed 
                  deer; mature females commonly have twins, while 
                  yearlings have only single fawns 
Age of Maturity - about 1 1/2 years for females; young males 
                  may not mate due to competition with older males
Lifespan - females as long as 22 years; males as long as 16 years;
           8 to 10 years is considered old for both
Antlers - males only; begin shedding in December and continues into
          March; mature and less healthy males may shed earlier
[35]


PREFERRED HABITAT : 
Mule deer are most likely to be found in open forested regions or on the
plains and prairies.  They prefer rocky or broken terrain at elevations
near or at the subalpine zone in the mountainous regions of the West
[8].  They are also found in alpine, montane, and foothill zones.  Mule
deer seek shelter at lower elevations when snows become deep.  In the
mountains of the Southwest, mule deer are found in lower elevation
shrublands, while white-tailed deer occupy the higher elevation montane
areas.  In open prairie regions mule deer tend to concentrate in river
breaks and brushy streambottoms [35].  In the high ranges of the Rocky
Mountains, mule deer migrate during winter, sometimes moving 50 to 100
miles (80-160 km) [35,54].


COVER REQUIREMENTS : 
Mule deer are better adapted to open areas than white-tailed deer,
although cover becomes important in winter.  Areas where cover can
prevent snow from accumulating beyond 12 inches (30 cm) are most
beneficial [18,39].  Wallmo and Schoen [53] reported that mule deer can
cope with snow up to 24 inches (60 cm) if not dense or crusty.  In
Alaska during winter black-tailed deer use old-growth forests at low
elevations, where forage becomes abundant after the stand exceeds 300
years in age and canopy cover is 60 to 80 percent [18].  During
snow-free periods, black-tailed deer move to less dense stands and
subalpine meadows [42].  In the Cariboo Region of British Columbia
winter range is defined as those areas with 10 to 45 percent slope,
having a south and/or west aspect, and below 4,950 feet (1,500 m) in
shallow to moderate snowpack zones, or below 3,300 feet (1,000 m) in
deep snowpack zones [1].  Lackenby and others [33] and Black and others
[5] listed optimal cover attributes for the Great Basin shrubsteppe
region, including estimates of tree heights and canopy closure for
thermal, hiding, fawning, and foraging cover.  They estimated the
proportion of cover to forage at 55 percent forage, 20 percent hiding
cover, 10 percent thermal cover, 10 percent fawn-rearing cover, and 5
percent fawn habitat.


FOOD HABITS : 
Mule deer are primarily browsers, feeding on several thousand different
plant species across their range.  They are capable of altering or
severely damaging plant communities through overbrowsing [40].  Mule
deer consume leaves, stems, and shoots of woody plants most often during
summer and fall, while grasses and forbs compose the bulk of spring
diets.  However, feeding behavior is quite variable in any given
location.  Some of the most common foods are:  rabbitbrush
(Chrysothamnus spp.), mountain-mahogany (Cercocarpus spp.), snowberry
(Symphoricarpos spp.), buffaloberry (Shepherdia spp.), ceanothus
(Ceanothus spp.), rose (Rosa spp.), serviceberry (Amelanchier spp.),
sagebrush (Artemisia spp.), sumac (Rhus spp.), common chokecherry
(Prunus virginiana), willow (Salix spp.), Gambel oak (Quercus
gambellii), mockorange (Philadelphus lewisii), ninebark (Physocarpus
spp.), antelope bitterbrush (Purshia tridentata), mariposa (Calochortus
elegans), juniper (Juniperus spp.), yucca (Yucca spp.), eurphorbia
(Euphorbia spp.), manzanita (Arctostaphylos spp.), lechuguilla (Agave
lechuguilla), western yarrow (Achillea millefolium), red huckleberry
(Vaccinium parvifolium), swordfern (Polystichum munitum), milkvetch
(Astragalus spp.), and dandelion (Taraxacum officinale).  Grasses
include bluegrasses (Poa spp.), wheatgrasses (Agropyron spp.), and
bromes (Bromus spp.) [17,18,19,21,25,30,35,36,42,48,49,56].


PREDATORS : 
Mule deer predators include humans, domestic dogs (Canis familiaris),
coyotes (Canis latrans), wolves (Canis lupus), black bears (Ursus
americanus), grizzly bears (U. arctos), mountain lions (Felis concolor),
lynx (F. lynx), bobcats (F. rufus), and golden eagles (Aquilla
chrysaetos) [35].


MANAGEMENT CONSIDERATIONS : 
The effects of logging on mule deer populations vary between and within
regions; therefore it is difficult to generalize conclusions [34].
Site-specific studies are required to determine logging effects,
although many studies confirm that slash depth is a major factor
limiting mule deer use of harvested areas [1,18,27,34,53].  Studies in
Alaska have shown that black-tailed deer avoid second-growth forests
after 20 to 30 years, and instead turn to "over-mature" forests (older
than 300 years) because these forests provide more browse than younger
stands [18,27,53].  Happe and others [19] have shown that forage in
coastal old-growth forests has higher crude protein values than forage
in clearcuts.  Tannin astringency of browse, which reduces digestive
protein, is higher in clearcuts than in old-growth forests.  Hanley [18]
recommended scattering clearcuts in old-growth in irregular shapes and
spreading them over a wide elevational range.

A study in Colorado showed that mule deer increased after 10 years
following a treatment of alternating clearcuts with uncut strips in
lodgepole pine-spruce-fir forests.  Strips 100 feet (30 m) wide produced
the best results [51].  Wallmo and Schoen [53] listed management
guidelines for timber harvesting that benefit deer in the western United
States.  However, they stated that some of these guidelines are based on
speculation and all contradict claims that large clearcuts are better
for mule deer.

Mule deer are vulnerable to a variety of viral, fungal, and bacterial
diseases [20].  They inflict heavy crop damage and damage to hayfields,
stackyards, and orchards, as well as reforestation projects.  Mule deer
are often attacked and killed by domestic dogs, and several hundred
thousand deer are killed by vehicles each year [40].  Mule deer are not
as tolerant of human activity and not as adaptable to disturbances as
white-tailed deer [40].


REFERENCES : 
NO-ENTRY

Related categories for Wildlife Species: Odocoileus hemionus | Mule Deer