Ungulates (Deer, Elk, Moose)

Damage Assessment

Pronghorn antelope, Antilocapra americana

Ungulate damage to various agricultural, forestry, and ornamental crops caused by feeding, trampling, and antler rubbing is an increasing problem. Deer browsing in winter on buds of apple and other fruit trees can reduce yields the following year (Austin and Urness 1989) or adversely alter the growth pattern of tree limbs (Harder 1970). Similar browsing on nursery plants and in Christmas tree plantations can reduce or eliminate their market value (Scott and Townsend 1985). Browsing of hardwood saplings and young fir trees in regenerating forests can reduce growth rates, misshape trees, and even cause plantation failures (Crouch 1976, Tilghman 1989).

Damage to trees caused by antler rubbing can be severe (Scott and Townsend 1985). Small trees (1/2 to 1 inch [1.6 to 2.5 cm] in diameter at 6 inches [15 cm] above ground) with smooth bark, such as green ash, plum, and cherry, were preferred for antler rubbing by white-tailed deer in an Ohio nursery (Nielsen et al. 1982).

Objective estimates of economic loss from ungulate browsing and rubbing in orchards, nurseries, and reforestation projects are difficult to obtain. Losses in yield or tree value may accumulate for many years after damage occurs and vary with other stresses, including rodent damage, inflicted on the plants. In Ohio, growers reported average losses to deer in 1983 of $82 per acre ($204/ha) for orchards, $89 per acre ($219/ha) for Christmas tree plantings, and $108 per acre ($268/ha) in nursery plantings (Scott and Townsend 1985). Losses apparently are in the millions of dollars annually in some US states (Black et al. 1979, Craven 1983b, Connelly et al. 1987).

Deer also feed on various agricultural crops, especially young soybean plants and ripening ears of corn. Hygnstrom and Craven (1988) estimated a mean loss of 2,397 pounds of corn per acre (2,680 kg/ha) for 51 unprotected corn fields in Wisconsin. Yield reductions in soybean fields are most severe when feeding occurs during the first week of sprouting (DeCalesta and Schwendeman 1978). Elk in some areas raid hay-stacks and cattle feedlots (Eadie 1954).

Damage Prevention and Control Methods

Exclusion

Woven wire fences of 8-inch (20-cm) mesh, 48 inches (1.2 m) high, near agricultural fields will help to curtail dam-age. Electric fences with two wires spaced at 8 to 10 inches (20 to 25 cm) and 3 feet (90 cm) above the ground will discourage pronghorns from entering croplands. A single strand of electric wire painted with molasses as an attractant and 30 to 36 inches (76 to 91 cm) above the ground will discourage pronghorn access.

Cultural Methods

Plant tall crops, such as corn, as a barrier between rangelands and small grain fields to help reduce damage. Alfalfa fields adjacent to rangeland are more vulnerable and apt to suffer damage. Pronghorns often move out of pastures that are heavily grazed by cattle to ungrazed areas.

Frightening

Propane or acetylene exploders may provide temporary relief from crop damage.

Repellents

None are registered.

Toxicants

None are registered, and poisoning pronghorns also violates state laws that protect them as game animals.

Trapping

This technique is for use only by federal or state wildlife agencies.

Shooting

Encourage legal hunting near agricultural fields to help curtail crop damage. Shooting permits are available in some states to remove pronghorns that are causing significant damage outside of the regular hunting season.

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