All deer are inclined to store some fat in autumn. Like other seasonal events in the whitetail’s life, accumulation of fat is cued to photoperiod and is hormonally controlled. During autumn, deer show a strong preference for energy-rich foods high in carbohydrates. Acorns, beechnuts and other starchy mast crops — as well as apples, cherries and other wild-growing and cultivated crops — are choice deer foods because they promote fattening. Few other natural forages provide more metabolizable energy or fattening power than oak acorns, and they grow almost anywhere. Acorn production can be increased through wise forest management, sometimes involving planting of new trees. Protection of large oaks and selective thinning is recommended, because acorn production is directly related to tree diameter and crown size. Food plots are not a substitute for proper forest and deer-herd management, but they add valuable diversity to the landscape. Most important, when carefully planned, food plots can target specific seasonal needs and provide forage much higher in digestible energy, protein, minerals and vitamins than typically is available naturally. Optimal autumn nutrition for deer won’t guarantee their winter survival — nor that of the unborn — but it certainly will increase survival prospects.
Deer Wintering Habitat Winter weather severity and the quality of coniferous deer wintering habitat govern the health and productivity of whitetail deer throughout the Northern Range, where winters are often prolonged. It’s not unusual to lose 30 percent or more of a wintering deer herd because of the combined effects of malnutrition and predation during a tough winter. However, if spring is delayed, 70 percent or more of the newborn fawn crop might die because fawns born to malnourished does are stunted and weak, the doe might not produce milk or pregnant does might abandon their fawns because of a resultant hormonal imbalance that interferes with maternal behavior. Even pregnant does that are food-stressed from January through March are likely to abandon 25 percent of their newborns, which ultimately fall victim to predators. Typically, northern deer populations demonstrate patterns of boom or bust, increasing during a series of mild winters only to crash after a tough winter. Most recently, this roller-coaster population pattern has been characterized by lower highs and lower lows, resulting in steadily declining deer numbers. Deer wintering habitat is changing across the Northern Range. More historic deer wintering areas, dominated by lowland conifer cover — commonly referred to as deer yards — are becoming overgrown, browsed-out or otherwise fragmented and degraded by poor forest management practices. Without proper management, these historic wintering areas lose their capacity to support viable deer populations. As an example, Michigan’s Upper Peninsula has always been good deer hunting country, even during the late 1800s and early 1900s, when whitetails were scarce to nonexistent elsewhere. Deer populations in this 16,800 square-mile region peaked at more than 700,000 in the early 1990s but have since decreased to fewer than 200,000 — probably fewer than before men arrived with axes and plows — despite more than 100 years of management. Even in New York, researchers have reported deer abandoning wintering areas they had used for 200 years and moving into residential Visit and Like Whitetail Institute at www.Facebook.com/WhitetailInstitute
Charles J. Alsheimer
Vol. 26, No. 2 /
WHITETAIL NEWS 23