Mule Deer

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Chordata
Class	Mammalia
Subclass	Theria
Order	Artiodactyla
Family	Cervidae
Genus	Odocoileus

Scientific Name

Odocoileus hemionus

Common Name

mule deer

Compiled by Whitney Cranshaw, Colorado State University:

Odocoileus hemionus

Damage and Diagnosis

Mule deer damage.

Throughout much of the region, no pest is more destructive and difficult to manage than the mule deer. (The white-tailed deer, Odocoileus virginianus, is also found in much of the region and causes similar plant injury.) Deer feed on a very wide variety of plants, depending on the season and the availability of alternative foods. Many vegetable crops may be browsed by deer feeding; the chewing of sweet corn ear tips and nipping of the center from heads of broccoli and cauliflower are examples. Deer also chew on twigs of fruit and ornamental trees, sometimes causing severe damage to younger trees. Feeding damage by deer is characterized by a ragged, wound. Deer (and elk) lack upper incisor teeth, which produce the clean cuts of other gnawing animals, such as rabbits.

Male deer may also damage trees by scraping them with their antlers during the late summer and fall rutting season. Young trees are a particularly common target for this practice.

Life History and Habits

Deer prefer areas of mixed vegetation and have been described as creatures of the forest edge. Ideal habitat for deer includes areas near shrubby plants that provide year-round food of leaves, twigs and buds and where denser growth is available for cover. This mix is sometimes produced by landscaping activities, which can attract deer into neighborhoods. Where deer have lost their fear of humans, they may prefer the plantings found in yards and become serious pests. Most deer feed during dusk and dawn. They may wander a half mile or more from resting areas to search for food. In the more northern areas, deer often gather in areas of dense cover for winter protection. Deer breed during late fall and bear young about 202 days later; peak numbers of births occur during May and June. Twin births are most common. The young fawns develop rapidly and some does may be able to reproduce when only six months old. Reproduction of deer is very dependent on the amount of available food. Deer are long-lived, with some individuals living almost twenty years. Hunting is the most important factor in deer life expectancy in most areas.

Legal Status

Deer are protected animals and are only to be killed during specified hunting periods by licensed hunters. Deer hunting within many communities is further restricted by local ordinances. In some cases, special permits may be issued by state wildlife agencies to farmers with specific deer problems.

Mechanical Controls

Exclusion

In areas where deer damage is severe, fencing provides the only satisfactory control. However, deer are excellent jumpers that can easily get over a typical 6-foot yard fence. They can also climb through or under fence openings less than a foot wide. Construction of a deer-proof fence is a substantial project. Among the various designs are the following.

Basic deer fence. A properly constructed fence built at least 8 feet tall will exclude deer. A thick wire mesh is best for this purpose and highly durable. Lighter mesh materials (chicken wire, plastic netting) can also be used, but these degrade rapidly. Unless well marked, the light mesh may not be seen by the deer, which may then accidentally push through. The fence should reach to the soil line to prevent deer from crawling under it. Solid wood or brick fences, through which the deer cannot see, may be somewhat shorter (6 to 8 feet) and still deter deer from jumping into the yard.

Slant fence. An outward-slanting fence can be more simply and cheaply constructed than an 8-foot vertical fence. For example, a 7-foot fence angled at 45° can usually deter deer. Deer will tend to approach and travel under the fence, then be unable to jump through it. However, the area under the fence should be kept mowed to encourage the deer to move under it.

Electric fence. A variety of effective electric fence designs have been proposed for excluding deer. Although not generally appropriate for most yards, these are much cheaper and easier to construct than fences built to physically exclude the deer. Deer will generally try to go under or through a fence, even if they could easily jump over it. Most electric fence designs encourage this habit so that the deer will touch the fence. After this “shocking experience,” deer will often learn to avoid the fence and stay several feet away. Since they usually jump from a point very close to the fence, their avoidance of the fence vicinity reduces their inclination to jump relatively low fences. A typical electric fence design would be about 5 feet in height with wires placed at 8- to 12-inch spacings. Usually wire spacing is shorter at the lower end of the fence. Alternatively, two shorter electrified fences, spaced 3 feet apart, can be used to exclude deer.

Repellents

Many different repellents have been attempted for deterring deer. Some of these are contact repellents, which act by taste. Contact deer repellents include hot pepper sauce (commercially available as well as home brews) and thiram (a fungicide and animal repellent). An important limitation of these contact repellents is their inability to protect the favored new growth that emerges after treatment. To make some of the less residual sprays, such as hot pepper, last longer during rainy periods, it is suggested to mix them with additives that reduce evaporation (e.g., Vapor-Guard, Wilt-Pruf). The commercially available contact repellents cannot be applied directly to food crops.

Area repellents protect plants by odor, and dozens of materials have been suggested. For example, human hair or blood meal are often suggested as repellents, although the general consensus of the seriously deer-plagued is that these are marginally effective at best. Bags of some brands of deodorant soaps are repellent. Also the manure and urine of large cats (provided by your obliging neighborhood cougar or zoo) or coyotes are more widely recognized as having fairly good repellent activity against deer.

Some commercial repellents appear to be the most promising. These include fermented egg solids (Deer-Away, MGK-BGR, Big Game Repellent) or ammonium soaps produced from certain fatty acids (Hinder). The latter is one of the few repellents that can be applied directly to plants that are to be eaten. A highly effective homemade repellent is a mixture of eggs blended with water. Crack the eggs and remove the small white membranous allantois, which tends to clog the sprayer. Blend in a 1:4 egg/water ratio and use this for a plant spray.

Dogs kept around garden areas will repel deer. However, unrestricted dogs are often not allowed in many residential areas, since they also may threaten livestock and other wildlife.

Some Trees And Shrubs That Are Least Likely To Be Browsed By Deer

Barberry	Red-osier dogwood
Forsythia	Honeylocust
Beautybush	Norway spruce
White spruce	Colorado spruce
Mugho pine	Austrian pine
Scotch pine	Common lilac
Southern sage	Four-winged saltbush
Quince	Rabbitbrush
Fernbush	Winged euonymus
Rose of Sharon	Vanhoutte spirea
Tatarian honeysuckle	Mountain ninebark
Potentilla	Wild plum
Nanking cherry	Gambel's oak
Fragrant sumac	Common hackberry
Hancock coralberry	Silver buffaloberry
Snowberry	Concolor fir
Common juniper	Mahonia
Pyracantha	Alpine currant

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.