Deer feed most actively at night but do browse off and on throughout the day near their bedding areas. The feeding behaviors of whitetails make the early hours of dawn and the later part of the afternoon the most productive hunting times.
Deer graze in the spring and summer months living on grass and small plants. In the fall, deer browse on brush and acorns. As winter sets in and the snow deepens, deer subsist on tips of brush, moss, bark, and the branches and twigs of various trees. Whitetails especially love cedar branches where found.
Toward midday, most deer will be bedded down and napping, although some animals will stand and browse periodically.
Although whitetails prefer certain browse plants, they are known to eat more than 600 kinds of vegetation.
The range of whitetails is roughly one square mile and within this small range most deer repeatedly use the same routes between bedding and feeding areas. Whitetails follow terrain contours that make for easy, unobtrusive travel - all the natural paths a man might take between high and low ground. A heavily used deer run is well marked with tracks and droppings, and sometimes grooved from heavy use. These trails can be misleading though as within weeks they can be abandoned or shift hundreds of yards if it becomes too watery or muddy or is blocked by a tangled deadfall. It may also move if the deer are attracted by vegetation sprouting in a new location or happen to come on an easier route as they amble off while browsing.
By the time snow gets near a foot deep, whitetails group together and yard up on south slopes, in valleys, or other relatively sheltered spots. South slopes provide warmth, sun, and protection from wind. Whitetails like hillsides where seeps, swamps, or running springs maintain good browsing after feeding becomes meager on ridges. The snow often prevents them from moving from the area that is over browsed and reluctant to leave when possible. The instinct of the whitetail hinders them from defying snow, wind, and cold in a hopeful search for better forage.
A deer will dig through two feet of snow to browse certain herbs at the ground level. Certain trees can be cut or bent to help ensure the survival of next season's game. Yellow birch and aspen can be cut part way through and bent over so that deer can reach the upper branches, and the trees will continue to grow. Aspen quickly replenish after being cut and offer great food stock. The red maple also offers another good food for deer in winter and its stump will sprout new shoots every time it is cut back.
When not yarded, whitetails are certain to be near one or more of their preferred foods. As the days lengthen deer feed on fresh maple buds. In spring and summer, whitetails seek sassafras, willow, blueberry, oak, sumac, Sweetfern, clover, buckwheat, corn, alfalfa, soybeans, and several less important wild foods including water lily. Deer will leave their cool, secluded beds when the afternoon heat is waning and go to water before much feeding.
The most heavily worn game trails lead to concentrations of preferred fall and early-winter foods. Deer especially love the acorns of oaks or apple orchards where fallen apples are softened by frost.
The favorite foods of Midwest whitetails include white pine, jack pine, ferns, arborvitae, bearberry, rose, fir, and strawberry bushes.
Deer feed most actively in the lowlands at night. On low ground whitetails can most clearly scent and hear approaching danger. At first light some of them climb and a few may already be on the high benches and ridges. The warming air produces rising thermals, and higher ridges allow whitetails a location where scent and sound will drift up to them.