October 2, 2009
What to Do About Deer
Deer in the garden eating our favorite plants will need some persuading to cut it out
Like other wild animals deer now thrive in some of the densest human settlements.
Some say that deer populations have expanded beyond acceptable limits, damaging yards and gardens, affecting forests, and posing hazards to drivers.
But deer cannot be reduced to the inconveniences their presence may cause.
And there is much to enjoy in sharing a habitat with this graceful, gentle wild neighbor.
- Plant selection and placement
- Electric fences
- Protecting trees
- Scare devices
Deer damage to plants is usually easy to identify.
Look for a ragged, square, torn appearance at the end of browsed twigs. Deer do not have upper incisors, so they don’t clip planys neatly, as do species such as rabbits or woodchucks.
An obvious sign that deer are at work is the height of browsing—three to five feet from the ground (or even higher where there’s snow).
The other and very obvious key to deer damage is its extent—generally favored plants are eaten pretty much completely. Many will grow anew if the browsing pressure is relieved, but others will not start new growth.
Woodlands in areas with a lot of deer may show a "browse line,” where the vegetation looks trimmed up to the height deer can reach. The forest floor is stripped of vegetation or completely covered by plants that deer don’t eat, such as ferns. Of course, the same or worse damage may occur where domestic livestock have been pastured for some time.
Deer sometimes damage small trees in what are called “buck rubs,” where males rub their antlers along the trunks. This is done to help off the “velvet,” or outer growth from hardening antlers. This activity happens most often in the fall, just before the start of rut (mating season).
Deer on the road have become a much greater concern as new roads are built through deer habitat, deer populations increase, and more deer move into suburban areas.
One of the best approaches to solving deer-related problems is with understanding and tolerance.
Not to say that all deer damage must be accepted, only that some damage is bound to happen where deer and people share the land. Farmers have learned this, and suburbanites can too.
Under heavy browsing conditions, either limit plantings to those plants that are the most resistant to deer browsing or use deer-proof fencing.
First things first. Take steps to deter browsers before they do damage. Seeing deer or signs of them (tracks and scat) around the yard can be a clear warning to be alert to early signs of browsing. If you can’t stop browsing before it starts, then act as soon as you see the signs of nibbling.
Young plants set out in spring are at risk to damage, often because forest plants have no yet "greened up." The garden plants, with their new growth, are especially attractive and tasty. As the garden plants mature and other foods become available in fields and woods, deer may naturally shift away from the yard. Plant covers and protective netting may be all you need to protect your plants at these times.
Consider this when planning to plant. You can reduce, and in some cases eliminate, deer damage using thoughtful landscape design that considers the selection and placement of plants. For instance, deer will eat some plants like hollies and barberries only when tender growth is appearing, if at all. Others (such as impatiens) are irresistible to deer all the time.
Deer feeding habits and favorites vary widely, even within a small geographic area. So the more local the advice you get, the better. Lists of plants that are tolerant of, or even resistant to, deer browsing are usually available at local nurseries, landscaping companies, or gardening clubs; neighbors may have valuable tips if they have been through deer wars and can suggest what works best in your new neighborhood.
When damage is slight to moderate, try growing a wider variety of plants and observing what is and is not preferred.
To the extent that it is possible, landscape with native plants that are known to be resistant to deer.
Where deer are a serious and chronic problem, the most effective way to protect crops or plants is with fencing. Over the long term, no other method, will be as effective.
Note: The average back yard fence may not be enough. When deer are really hungry, they will jump fences up to eight feet high (some say even higher).
There are a variety of fences ranging from high-tensile strand wired to solid posts to woven mesh chain link or various types of electric wiring. The best type depends on the area and the situation, so check with local extension agents or wildlife specialists before buying anything.
Electric fences can work very well in deterring deer, and the simplest and least expensive of these are single-strand fences that work on the principle of attracting rather than repelling them.
Deer are well insulated, thanks to their dense hair coats and poorly conducting hooves. Where they may walk through a single strand of electric fencing, they can be enticed with "bait" to approach the fence and contact it with nose or tongue, making sure that the lesson is delivered to these more sensitive parts of the body. Aluminum foil with a dab of peanut butter or metal bottle caps wired to the fence with cotton fillers soaked with apple or other fruit scents have quite effective in keeping deer out of small gardens.
You can prevent "buck rubs" by wrapping trees with any commercial product sold for that purpose or placing corrugated plastic sleeves around trunks.
Erect a temporary fence around vulnerable tress (usually smaller, two- to three-inch-diameter trees that stand alone) or simply surround them with two-inch diameter garden stakes that are at least 4-5 feet high and serve to deflect any rubbing onto them.
A variety of products, including some homemade, can repel deer.
Deer are extremely wary animals who will avoid places in which they feel threatened or insecure. If you immediately launch a concerted effort to repel deer at the first sign of their presence (tracks or early browse), you’re more likely to be successful.
Here are some tips:
- Try homemade strategies first if possible to save time and money. Hanging bars of soap on individual trees or shrubs where you want protection sometimes does the trick, particularly brands of soap that are high in tallow fatty acid like Irish Spring. Others, such as glycerin soaps, will not work. With any strategy, moving things around and switching types of products will help keep deer on their toes and make them wary.
- Commercial repellents can work effectively by making plants taste unpleasant to deer, or by repelling deer with sulfurous odors (e.g. rotten eggs), believed to induce fear by giving off smells that deer associate with a predator.
- The key is to start using repellents before, or as soon as, you notice damage. Be diligent about reapplying regularly — every two weeks and after heavy rains. Alternating differing kinds of repellents may also help.
- Predator urines are increasingly popular in garden supply stores, but have not scored well in studies which measured the effectiveness of various repellents. In addition, the sources of these products are "fur farms," which raise wild animals for their pelts. Animals at these "farms" suffer from terrible, cramped conditions and die extremely inhumane deaths. For this reason alone, predator urine products should be avoided.
The key to using scare devices is to couple them with other strategies (repellents, for example) and to vary them, moving them around the yard or garden, or changing the place from which the frightening stimulus comes (when this can be done).
- Scarecrows and effigies may successfully deter hungry deer, especially if the effigies move, so they appear threatening.
- Lights, sprinklers, and alarms on motion sensors may help protect gardens, or at least alert the homeowner to deer's presence.
- Scare tape or balloons may also frighten deer.
Some report that unleashed dogs kept on their property by “invisible” fence set-ups keep deer away. We have concerns for dogs when owners rely on these fences, and we have serious problems with letting dogs run off leash.
But dogs may be helpful: There is little doubt that deer acknowledge dogs as enemies and avoid them. So, having a dog "mark" your yard as her territory may deter deer, and dropping any hair combed from the dog around the yard may have some value as a deterrent. The dog will want to use the yard anyway, and probably be brushed as well, so the effort can be justified as one that keeps her happy.
Strategies to deal with the issue of deer-care collisions must occur at the community level as well as through cooperative work with transportation agencies.
Experiments with roadside reflectors have taken place in communities across the country, and even more sophisticated technology with sensors that detect possible animal movement near roads and warn oncoming drivers is now being tested.
These technologies have their critics, but time will tell whether any of them is truly successful.
One thing time has already told us is that there is no evidence that deer warning whistles mounted on a car’s hood or bumper or ultrasonic devices work.
What may be true, though, is that people who go to the trouble to mount them on the car are likely to be more alert to the possibility of deer on roadways, and their attentiveness might reduce the chances of their colliding with deer.
One key to avoiding collisions with deer is driver attentiveness, a subject of much discussion in these days of text messaging and cellular phones. Paying special attention at dusk and dawn in areas where deer are known to frequent is critical.
When a deer bolts across the road, it's very likely that there are more to follow. So if you see a deer by or in the road, take caution before proceeding. It's important to bear in mind that deer move about a lot during the late fall and early winter (during the period of mating called the rut). Drivers and deer would both be safer if every driver’s education course taught students to adhere to speed limits and take it slow whenever deer are around.
People call wildlife agencies and wildlife rehabilitators about "orphaned" fawns they find in woods, fields, backyards, or roadsides.
It is perfectly natural in the spring to come across a deer fawn by herself in the woods.
The fawn is actually not alone; her mother is nearby, aware, and attentive. To keep from attracting predators does leave their young hidden except when feeding them.
If you find a fawn like this, leave her alone knowing that a concerned and anxious mother is nearby and will take care of her once you leave.
Deer may be an important host for the ticks that carry Lyme disease; however, their role in the spread and frequency of the disease is debated.
Mice and other small mammals are important hosts of pre-adult ticks, and scientists now think changes in their numbers are more important than deer numbers to Lyme disease prevalence in humans.
Small-mammal numbers are often largely dependent on acorn production, so ultimately, oak trees may be the determining factor.
It may be easy to blame deer as the "cause" of Lyme disease when the ecology of this wildlife disease is more complex than simply counting deer.
» Download The HSUS's Living with Wild Neighbors in Urban and Suburban Communities: A Guide for Local Leaders.
» There are many popular books and websites that provide information on deer. A technical paper that we recommend is Allen Rutberg’s chapter "The Science of Deer Management: An Animal Welfare Perspective," in The Science of Deer Management (Smithsonian Institution Press, 1997). Copies can be requested directly from The HSUS.
» If you are located within the D.C. Metro Area, take advantage of our wildlife conflict resolution service. Learn More
» Purchase a copy of Wild Neighbors; the go-to guide for useful, humane solutions to conflicts with wildlife.