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Feeding Deer in Winter Often Does More Harm Than Good

December 21, 2009 - Hunting season is over and though the hunters may be out of the woods, the deer aren't yet. Are they going to make it through another Maine winter? If it's as bad as the past two, how many (or how few) will survive? Maine's deer herd is already well below what it could, and should, be, and one more harsh winter could push it to a point that might take a decade or more for recovery. Hunters and non-hunters alike want to do what we can to help more deer make it through the winter. But the road to disaster is often paved with good intentions.

While still legal in Maine, winter deer feeding is a serious violation of the laws of nature.

Biologists use the term carrying capacity to refer to the number of animals an area can support without degrading the environment or the health of those animals. Variables that determine carrying capacity are called limiting factors. In Maine, for instance, quantity and quality of winter food is often the limiting factor in determining how many deer an area can support.

In spring, summer and early fall, high-quality deer food exists in abundance throughout our state, even in the farthest northern reaches. But in fall, vegetation dies or goes dormant. Except for areas that may have experienced an abundant (though unpredictable) mast crop, or small pockets of agricultural land where crops are left fallow, the nutritional value of food drops precipitously.

Each deer requires a certain amount of nutrition, and if there isn't enough to go around, some will perish.

Unfortunately, it's not quite as simple as some dying and others living. When an overabundance of deer compete for a limited resource, they all suffer. In the process, they also degrade the habitat. Unless some other catastrophe such as severe winter conditions or excess predation occurs, the habitat quality and thus the carrying capacity will be diminished, and the area will be able to support fewer deer in subsequent years.

While it's little solace to the sportsmen of Maine – and anyone who derives an income from hunting – the harsh winters and rampant predation of recent years may actually have some ecological benefit. At least they would if deer were the only thing altering habitat. Unfortunately, that's not the case either. Maine's chief industry – logging – directly competes with its next most important source of income – outdoor recreation – by further degrading winter habitat.

In their natural environment, deer have evolved to respond to the decline in winter nutrition. Their bodies go through a metabolic shift, where body functions, including digestion, slow down. They become less active and thus burn fewer calories. Their digestive systems also change to accommodate the shift from a fall diet that's typically high in carbohydrates and fats to a winter diet that's high in fiber (woody browse) but nutritionally very poor. Feeding them the wrong kind of food now potentially can be very harmful. In the heart of winter, a deer can actually die of starvation with a belly full of hay. And feeding them corn at this time of year is like running pure gasoline through your chain saw without mixing in oil.

There are other negative aspects to winter deer feeding as well. Artificially concentrating deer on already marginal habitat only degrades it further, setting the table for an eventual disaster – and that habitat could represent someone's livelihood. Pushed into tight quarters and competing for a limited food source places additional stress on deer during their most stressful season. The proximity increases the possibility for spreading disease, and the additional stress lowers their resistance should they contract something.

Most folks who feed deer do so close to home, so it also brings deer closer to humans. This can lead to an increase in car-deer collisions. It makes deer, whose mobility is limited by deep snow, more vulnerable to free-roaming dogs, which kill not for food but simply because that's what they're programmed to do. Perhaps worst of all, having deer close to humans changes people's perceptions. They no longer view the deer as wild creatures, seeing them instead as pets – their deer.

The situation is not hopeless, though the most effective remediation requires some planning. If you must feed, provide the right food. Cutting firewood (or timber) and leaving the tops could be far more beneficial than dumping corn or hay on the ground. Furthermore, the stumps you leave will sprout suckers next spring, providing more woody browse the following winter.

Cover is just as important as food. During periods of deep snow and intense cold, deer may lay up for several days without feeding to conserve body heat and fat stores, the latter of which they'll live off for most of the winter. Dense softwood cover reduces heat loss by buffering wind and allows deer to move about more easily by reducing snow depth. That's why it's important to protect a certain amount of softwood cover, the more the better. And the closer that food and cover are to one another, the more beneficial each is.

You can also manage the habitat by protecting, enhancing and even planting winter food species. Acorns and beechnuts are great sources of fall and winter nutrition. Larger, older trees typically produce more nuts, but make sure there's enough regeneration for future years. On good ground, you can plant turnips. Deer will eat the greens in fall and the root bulbs in winter. On poorer ground, even starvation foods like hemlock and cedar may provide some benefit. The key is to give them what they need, not what you think they need.

BOB HUMPHREY, Portland Press Herald, December 17, 2009


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