As soon as the first few inches of snow falls, some New Hampshire landowners begin thinking about putting out food for the deer.

Don’t! You’ll do more harm than good, both to the deer and to their habitat. Research and experience have shown that the negative effects of winter feeding outweigh any benefit deer might get from being fed.

Two factors primarily determine deer survival during winter: the availability of high-quality food in the fall, and softwood (e.g., hemlock, spruce, fir) cover during winter.

Deer must store body fat for the winter. The amount of body fat a deer has when it enters the winter directly determines if it will survive until spring. Deer accumulate body fat by increasing the amount of food they eat in September and October, when high-quality foods, such as acorns and beech nuts, are abundant. By November, most deer have accumulated all the fat they will need to survive the winter.

During September and October feeding, fat accumulation in adult deer results in a 20 to 30 percent increase in body weight. Fawns, on the other hand, accumulate only about half as much fat, because they use most of the food they eat for growing muscles and bones.

Beginning in November, deer in the Northeast voluntarily begin eating less. They continue to reduce the amount of food they eat each day until around late February, when they are eating about 50 percent less food per day than they did in September. Throughout the winter, deer compensate for their reduced food intake by relying on their stored fat for energy. An adult deer may get as much as 40 percent of its daily nutrition during winter from fat reserves.

However, to maintain this level of stored fat use, deer must conserve their energy by reducing their activity (e.g., by traveling less) and by spending most of their time in softwood cover, where it’s warmer and the snow isn’t as deep. These energy-conserving behaviors are especially important for fawns because of their lower fat reserves.

Although deer can eat to reduce the amount of fat they burn, natural foods only slow the rate of fat loss; they don’t stop it. This is where some people begin saying, “That’s why people need to put out grain for the deer!”

But research has discovered that even deer feeding on nothing but grain lose weight during the winter. Even captive deer that have access to as much high-quality food as they want still reduce the amount of food they eat beginning in November, and they continue to lose body fat through February.

That’s because deer have evolved a survival strategy that involves eating as much food as they can in autumn, to put on as much fat as possible before winter. Once winter comes, instinct tells deer to eat less, move around less, and seek the protection of winter cover.

Research also shows that large, dominant adult deer fill their bellies first at feeding sites, which means that smaller and weaker individuals, including the vulnerable fawns, will have wasted valuable energy traveling to the feeding site, where they may get little feed. Over time, feeding sites attract more and more deer competing for the same food supplies, leading to over-browsing and degradation of the natural habitat around a feeding site, as well as wreaking havoc on homeowners’ ornamental plantings.

Wildlife biologists also worry that deer feeding might help spread Chronic Wasting Disease (CWD), which affects deer and elk and is always fatal. To date, CWD has been found in 14 states, including New York, although it hasn’t been found in New Hampshire.

Although biologists don’t know exactly how this disease spreads, they believe its transmission requires close contact between animals. When humans put out food for deer, they create a situation where an unnaturally high number of deer become concentrated in a small area.

In fact, some states have banned winter feeding of deer to help stop the spread of CWD. Feeding deer because you just like to watch them is a selfish reason for placing our deer resource at so much risk.
 
So, what can you do if you want to help deer during the winter? You can work on your property and with your neighbors to create and maintain quality deer habitat. This includes working in stands of oak and beech to increase the amount of nuts available in autumn, working in softwood stands to maintain and create dense winter cover, and working in hardwood stands to increase the amount of woody browse available to deer. Together, landowners, hunters, and wildlife enthusiasts can ensure there will be enough habitats to sustain many generations of deer in New Hampshire.

By Matt Tarr, Educator, UNH Cooperative Extension Forest Resources

For more information call the UNH Cooperative Extension's Family, Home & Garden Center's Info-line (toll free) at 1-877-398-4769 or send us an email. Volunteers are available to answer your questions Monday through Friday 9:00am to 2:00 p.m.