Winter feeding is Not the key to deer survival in the northeast
By Matt Tarr, Whitetail Stewards, Inc.
As winter dumps a few more inches of snow in the northeast you or your clients may be thinking about putting out some food for the deer. Don’t do it; you will be doing more harm than good to both the deer and their habitat. Research and experience shows overwhelmingly that any benefit deer might get from being fed is outweighed by the negative effects associated with winter feeding.
My background
While a graduate student at the University of New Hampshire I spent nearly three years studying the effects of winter feeding on wild deer in northern NH and I spent many years raising captive whitetails at the UNH deer farm. As an avid hunter and I spend hundreds of hours in the field each year hunting, filming and learning about deer in their natural habitat. As a forester and wildlife biologist I help landowners and hunters create and improve deer habitat on their properties throughout the country. Let me share some of my experiences with you and explain why winter feeding doesn’t benefit deer. Additionally, I’ll explain how landowners and natural resource professionals can improve the winter survival of deer through proper habitat management.
Two main factors determine deer winter survival
Before I discuss winter feeding let me explain some basic deer biology, specifically, how deer have evolved to survive winter in the northeast. You probably already know some of this, but some of it may surprise you. First, deer survival during winter is determined primarily by two things: the availability of high-quality food in autumn, and softwood (e.g., hemlock, spruce, fir) cover during winter. So, how do each of these things affect deer survival?
Body fat accumulation in autumn
As you know, deer 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. During these two months, fat accumulation in adult deer results in a 20-30% increase in body weight. Fawns on the other hand, accumulate only about half this much fat, because most of the food they eat is used for growing muscles and bones. By November, most deer have accumulated all of the fat they will need to survive the winter.
Deer voluntarily reduce food consumption in winter
Beginning in November, deer in the Northeast do something surprising; they voluntarily begin eating less food! Deer continue to reduce the amount of food they eat each day until around late-February, when they are eating about 50% less food per day than they did in September. During winter, deer compensate for eating less food by relying on their fat reserves for energy. In fact, an adult deer may get as much as 40% of their daily nutrition during winter from fat reserves. However, a healthy deer can only maintain this level of fat use for about three months, so it must conserve its fat. Deer conserve fat and the amount of energy they need by reducing their activity (e.g., they travel less) and by spending most of their time in softwood cover, where the snow is less deep and temperatures are warmer. These behaviors that conserve energy are especially important for fawns because they have fewer fat reserves than adult deer.
Energy conservation is the key to deer winter survival
Therefore, energy conservation is the key to reducing fat loss in deer during winter. Although deer can eat food to reduce the amount of fat they burn, natural foods only slow the rate of fat loss; they don’t stop it. This is probably where you are saying, “That is why people need to put out grain for the deer!” Well guess what; 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. I have measured it myself in controlled experiments with captive deer at UNH, and I have measured it at winter feeding sites in northern NH. The fact is, deer simply do not eat enough food to maintain their weight in winter. Why on earth do they do this? It’s because deer have evolved with a survival strategy that tells them they need to eat as much food as they can in autumn, in order to put on as much fat as possible before winter. Once winter comes, instinct tells deer that they need to rely on their fat reserves for energy, and reduce the amount of energy they burn, by not traveling and by seeking the protection of winter cover.
Deer increase energy expenditure to get supplemental food
So, now that you’ve read the above “crash-course” on deer biology, why doesn’t putting out grain or other foods help the deer in winter? First, consider the results from a recent research project, conducted in part by UNH, that looked at the diets of deer visiting places where people put out grain in the winter. Specifically, the study analyzed deer fecal pellets collected at over 70 winter feeding sites located throughout NH. To date, the researchers found that on average, grain accounted for less than 30% of the food eaten by deer each day. So why is this harmful to the deer? Well, consider that every deer burned some of its limited fat reserves to travel to a feeding site, but only got a small amount of food. If a deer did this only once per day it may not be so bad; however, most deer normally visit a winter feeding site a few times per day. Wild fawns I radio-collared during my research in NH visited feeding sites an average of three or four times daily. Compared to deer not being fed, deer around feeding sites probably increase their daily activity in an attempt to get some grain, which often isn’t there. If a deer does this every day, you don’t have to be a biologist to conclude that they are probably burning far more energy (fat) then they get from the grain. These deer would have been much better off if they conserved their energy and visited a natural food source only once or twice each day.
Healthiest deer eat most of the food
The results from the study I mentioned above suggested that grain comprised less than 30% of the food eaten each day by the average deer. So what about the deer that got more than this? In my experience, it’s a small number of deer that are responsible for eating the majority of the grain at a feeding site. If you haven’t noticed it before, pay attention the next time the deer come to your food pile. You will see that there are a few individual deer that always eat first, while the other deer watch and wait for a chance to sneak in and get food. Sometimes it’s a buck, but more often it’s a dominant doe and one or two of her adult offspring that push the other deer away and eat most, if not all, of the food. You will see that fawns are almost always the last deer to eat at a feed site, and they rarely get a belly full of grain. This is unfortunate, and here’s why I think it is one of the greatest negative effects of winter feeding. Fawns are the portion of the herd that could benefit the most from winter feeding because they have limited fat reserves and they must eat during winter to survive. However, when fawns follow adults to a feeding site they generally have to wait on the sidelines while the adults eat all of the grain. So what happens to the fawns, and to the less dominant deer that get only a few bites of food, or get no food at all? Those deer waste energy reserves they can’t spare when they travel to and from that feeding site. If this happens on a daily basis, and more than once per day, it can result in a significant amount of energy wasted over the course of the winter and can potentially decrease winter survival of these deer. Not quite what you intended when you put out food.
Deer in poorest condition get little food
You may be saying, “Well at least winter feeding benefits those few deer that eat all of the feed.” It’s possible that’s true, but consider this. Those dominant deer at a winter feeding site are also dominant in other seasons; those deer get their choice of food in the autumn and are able to put on a thick layer of fat. Therefore, the majority of those big dominant deer would survive winter regardless of how severe it is. So basically, the healthiest deer in the herd get all the feed, while deer in the poorest condition waste energy they can’t spare. Not much of a benefit if you are interested in a healthy deer herd.
More grain means more deer
So is putting out more grain the key to helping the deer? The answer is no. Although it would seem like putting out more grain would give more deer a chance to get food, this is rarely the case. Experience has shown that putting out more grain only attracts more deer. The story is the same everywhere I go; people who are now feeding 25 or more deer all say they were feeding only a handful of deer the first few years they put out food. Deer learn where to go in the winter from their adult relatives. Deer that are fawns this winter will eventually have fawns themselves; they will bring their offspring to the same areas their parents brought them. Sometimes it takes three or more years before you see a large increase in deer, then almost overnight, you’ve got twice as many deer trying to eat the same amount of food. At many supplemental feeding sites it’s not uncommon to see 40 or more deer feeding at one time. You can only imagine what that many deer do to the natural habitat around a feeding site, especially if grain makes up only a small portion of their food requirements.
Dangers of chronic wasting disease
Here’s one final point to consider. Over the past couple of years I’m sure you have heard about Chronic Wasting Disease (CWD). Chronic wasting disease affects deer and elk and is always fatal. To date, CWD has been found in wild deer in eight US states and at least one Candian providence. Although biologists don’t know exactly how this disease spreads, it is believed that close contact between animals is required. When we put out food for deer, we create a situation where an unnaturally high number of deer are concentrated in a small area. Biologists agree that winter feeding creates a serious risk for spreading diseases such as CWD between deer. In fact, some mid western states have banned winter feeding of deer to help stop the spread of this terrible disease.
As hunters and sportsmen, we need to be proactive on issues such as CWD and assume responsibility for our actions. Feeding deer because you think it does them good, or because you just like to watch them, are poor reasons for a “sportsman” to place our deer resource and hunting heritage at so much risk.
How to help deer survive winter
So what should you do if you want to help deer during the winter? You can work on your property and work with your neighbors to create and maintain quality deer habitat. This includes: working in forested 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. It is time that sportsmen and women, landowners, and professionals take an active role in the proper management of deer and their habitat. If all parties work together, we can ensure there will be enough habitat to sustain many generations of deer in the northeast.
Want more information?
Click on any of the links below for more information on supplemental feeding of deer:
So why is this harmful to the deer? Well, consider that every deer burned some of its limited fat reserves to travel to a feeding site, but only got a small amount of food. If a deer did this only once per day it may not be so bad; however, most deer normally visit a winter feeding site a few times per day. Wild fawns I radio-collared during my research in NH visited feeding sites an average of three or four times daily. Compared to deer not being fed, deer around feeding sites probably increase their daily activity in an attempt to get some grain, which often isn’t there. If a deer does this every day, you don’t have to be a biologist to conclude that they are probably burning far more energy (fat) then they get from the grain. These deer would have been much better off if they conserved their energy and visited a natural food source only once or twice each day. 
next time the deer come to your food pile. You will see that there are a few individual deer that always eat first, while the other deer watch and wait for a chance to sneak in and get food. Sometimes it’s a buck, but more often it’s a dominant doe and one or two of her adult offspring that push the other deer away and eat most, if not all, of the food. You will see that fawns are almost always the last deer to eat at a feed site, and they rarely get a belly full of grain. This is unfortunate, and here’s why I think it is one of the greatest negative effects of winter feeding. Fawns are the portion of the herd that could benefit the most from winter feeding because they have limited fat reserves and they must eat during winter to survive. However, when fawns follow adults to a feeding site they generally have to wait on the sidelines while the adults eat all of the grain. So what happens to the fawns, and to the less dominant deer that get only a few bites of food, or get no food at all? Those deer waste energy reserves they can’t spare when they travel to and from that feeding site. If this happens on a daily basis, and more than once per day, it can result in a significant amount of energy wasted over the course of the winter and can potentially decrease winter survival of these deer. Not quite what you intended when you put out food. 
Experience has shown that putting out more grain only attracts more deer. The story is the same everywhere I go; people who are now feeding 25 or more deer all say they were feeding only a handful of deer the first few years they put out food. Deer learn where to go in the winter from their adult relatives. Deer that are fawns this winter will eventually have fawns themselves; they will bring their offspring to the same areas their parents brought them. Sometimes it takes three or more years before you see a large increase in deer, then almost overnight, you’ve got twice as many deer trying to eat the same amount of food. At many supplemental feeding sites it’s not uncommon to see 40 or more deer feeding at one time. You can only imagine what that many deer do to the natural habitat around a feeding site, especially if grain makes up only a small portion of their food requirements. 