The information below is from the New Hampshire Fish and Game departments website.
Habits and Habitats
White-tailed deer can live in a variety of habitats, including farmlands, brushy areas, woods, mountains, and suburbs and gardens. They feed on green plants, including aquatic species in the summer, acorns, beechnuts, and corn in the fall, and woody vegetation, including buds and twigs of birch, maple and conifers in the winter. White-tailed deer will typically consume 5 to 9 pounds of food each day and find water from snow, dew and water bodies.
Individual deer group into two types of social combinations. These include the family group, with a doe and her young, and the buck group. The family group will stay together for approximately a year. Buck groups are structured with a dominance hierarchy of 3 to 5 individuals. Bucks will challenge each other with stares, lowered ears, kicking, sparring (physically pushing each other back), and less commonly, thrashing of forefeet.
During the winter, these two deer groups may come together, forming communities of up to 150 individuals in locations called “yards.” This unification keeps trails open and accessible for feeding and also provides protection from predators. However, there have been problems with humans providing supplementary feed sites for deer in the winter. These sites can cause unnaturally high densities of congregated deer that attract predators, increase the risk of disease transmission, increase aggression within the community, and lead to over-browsing of local vegetation and more deer-vehicle collisions. They cause deer to be more dependent on humans and artificial food sources that provide few benefits.