White-tailed deer are a widespread species across Maine, thriving in diverse habitats. Their ability to flourish is closely tied to their varied diet, which shifts significantly throughout the year, reflecting seasonal plant availability and nutritional needs. Understanding what these herbivores consume is important for appreciating their ecological role and managing interactions with human activities.
Natural Foraging: The Primary Diet
White-tailed deer are primarily browsers and grazers. Their natural diet largely consists of “browse,” including twigs, leaves, and buds of woody plants. In Maine, deer frequently feed on maple, birch, aspen, willow, and the year-round needles of white cedar and balsam fir.
Forbs (broad-leaved herbaceous plants) also form a substantial part of their diet, especially during warmer months. Examples include clover, asters, and goldenrod, which provide essential nutrients. Mast, such as nuts and fruits, is another important food source. Deer consume acorns, beechnuts, and wild fruits like apples, blueberries, and raspberries when available. They are highly selective, choosing the most nutritious plant parts.
Seasonal Shifts in Deer Diet
The diet of white-tailed deer in Maine changes with the seasons, adapting to vegetation availability and nutritional content. In spring, as new growth emerges, deer focus on tender shoots, emerging forbs, and highly digestible new leaves of hardwood plants. This helps them regain weight lost during winter.
During summer, abundant green vegetation allows deer to consume a variety of forbs and early fruits like berries. This high-quality forage supports lactating does and growing fawns, building energy reserves. As fall approaches, their diet emphasizes mast crops like acorns and beechnuts, rich in carbohydrates and fats, to accumulate fat reserves for winter.
Winter presents the greatest challenge, with deer relying heavily on woody browse such as twigs and buds from dormant trees and evergreen needles like white cedar and hemlock. Their metabolism slows, and they draw upon stored fat reserves, which can account for up to 40% of their daily nutritional needs. When other food is scarce, deer may resort to less preferred browse like spruce or balsam fir.
Human Influence on Deer Foraging
Human landscapes influence what deer consume, leading them to agricultural fields and residential areas. Deer forage in agricultural crops, including corn, alfalfa, soybeans, and oats, which provide concentrated food sources. This can result in damage to farmers’ livelihoods.
Residential gardens also become attractive foraging grounds for deer, where they consume vegetables, ornamental plants, and fruit trees. While some individuals engage in supplemental feeding of deer, such as grain or hay, this practice has negative consequences. It can concentrate deer, increasing the risk of disease transmission and aggression among animals. An abrupt change to an inappropriate diet, especially in winter, can also disrupt a deer’s digestive system, potentially leading to starvation even with a full stomach.
What Deer Avoid
Deer avoid certain plants due to unpalatable taste, strong odors, physical deterrents, or toxicity. Plants with fuzzy foliage, like lamb’s ear, are less favored due to their unpleasant texture. Similarly, plants with strong herbal or pungent scents, such as salvia, lavender, and ornamental chives, deter deer.
Deer instinctively avoid many poisonous plants, recognizing those that can cause illness. Common plants in Maine that deer often bypass include daffodils, monkshood, foxglove, and certain evergreens like boxwood and American holly. While no plant is entirely deer-proof, especially during extreme hunger, these species are consistently less preferred.