Overview of Damage Prevention and Control Methods
Widespread habitat modification is not recommended for the control of damage caused by deer. Destruction of wooded or brushy cover to reduce numbers of deer destroys valuable habitat for other wildlife. Deer forage over a large area, so it is impractical to eliminate all food for deer in an area.
Harvest crops as early as possible to shorten the period of vulnerability to deer. Plant crops that are favored as far from wooded cover as possible to reduce the potential for severe damage. In addition, lure crops can be planted to attract deer away from highways and fields. The effectiveness of lure crops is variable and artificial food sources may eventually increase deer densities and problems. Specific recommendations are not yet available regarding plant selection, timing, and proximity of lure crops.
Damage to woody ornamental plants can be minimized by selecting landscape and garden plants that are less preferred by deer. In many cases, original landscaping objectives can be met by planting species that have some resistance to damage caused by deer. Several plant lists are available online, but none are fool-proof. Check with your local Cooperative Extension office for a list of deer-resistant plants for your area.
Fences may be the only way to minimize damage effectively where deer are abundant or crops are particularly valuable. Several designs are available to meet specific needs:
- Baited, polytape electric fences are simple, inexpensive, and useful for protecting garden and field crops during snow-free periods.
- Permanent, high-tensile electric fences provide year-round protection from deer and are best suited to high-value specialty or orchard crops. The electric shocking power and unique fence designs present both psychological and physical barriers to deer.
- Permanent woven-wire fences provide the ultimate deer barrier. They require little maintenance but are expensive to build.
- Gas exploders set to detonate at regular intervals are the most commonly used frightening devices for deer.
- A guard dog that is restricted by an invisible fence system or physical fence can keep deer out of a limited area, but care and feeding of the dog can be time-consuming.
- A bio-acoustic frightening device called DeerShield was developed recently. It employs motion-activated sounds designed to frighten deer.
- Deer-Away® Big Game Repellent (37% putrescent whole egg solids) is an odor and taste repellent that has been used extensively in western conifer plantations. It is reported in field studies to be 85% to 100% effective. It is registered for use on fruit trees prior to flowering, as well as ornamental and Christmas trees. Apply it to all susceptible new growth and leaders.
- Hinder® (15% ammonium soaps of higher fatty acids) is registered for use on edible crops. Apply it directly to vegetable and field crops, forages, ornamentals, and fruit trees. Effectiveness usually is limited to 2 to 4 weeks but varies because of weather and application technique. Re-application may be necessary after heavy rains.
- Thiram (7% to 42% tetramethylthiuram disulfide) is a fungicide that acts as a taste repellent, most often used on dormant trees and shrubs. A liquid formulation is sprayed or painted on individual trees. Adhesives such as Vapor Guard® can be added to increase resistance to weathering.
- Miller’s Hot Sauce® Animal Repellent (2.5% capsaicin) is a taste repellent that is registered for use on ornamentals, Christmas trees, and fruit trees. Apply the repellent with a sprayer to all susceptible new growth, such as leaders and young leaves. Do not apply to fruit-bearing plants after fruit set. Vegetable crops can be protected if sprayed prior to the development of edible parts.
- Plantskydd® Animal Repellent is made from dried animal blood. It is available in powder concentrate or ready-to-use liquid. It is suitable for use on organic farms. Do not apply to plants destined for consumption.
No toxicants are registered for control of deer.
Effective use of legal deer hunting is the best way to manage populations. By permitting hunting, landowners provide public access to a resource, while simultaneously reducing damage by deer. The daily and seasonal movements of deer rarely allow for a single landowner to control all land used by deer; neighboring landowners should cooperate. Landowners, state wildlife agencies, and local hunters should reach agreement about a desirable level for the deer in an area.
Methods for managing deer in a specific area already exist in most states. Either-sex seasons, increased bag limits, antlerless only permits, special depredation seasons, and a variety of other management techniques have been used successfully to reduce numbers of deer to below levels achieved by “buck only” regulations. Bow hunting from stands can be an effective way to reduce the number of deer in urbanized areas where use of firearms is not appropriate or accepted.
Depredation permits issued by some states allow for removal of deer where they are causing damage during non-hunting periods. Some communities and landowners may use “Earn-a-Buck” or other managed hunts to control populations of deer. The removal of does is essential for reducing the number of deer and associated damage.
Herds of deer can be reduced dramatically through sharp-shooting over bait (Figure 19). Recommended equipment includes .223-caliber rifles and use of frangible bullets. Frangible bullets will penetrate the skull of the deer but not exit, thereby increasing safety. Properly placed head-shots will kill a deer instantly. Shooters should demonstrate the ability to hit a 1-inch target at 50 yards consistently before using this method. The use of night-vision scopes and sound-suppressed firearms will enhance effectiveness (where legal). Appropriate permits are necessary from state wildlife agencies.
- Cage traps
- Drop nets
- Cannon nets