White-tailed deer are highly adaptable ruminants whose diet is determined less by strict preference and more by immediate opportunity, nutritional need, and geographical location. As generalist herbivores, deer consume a wide variety of plant material, often selecting the most digestible and nutrient-dense forage available. Their ability to process diverse vegetation allows them to exploit food sources other herbivores might avoid. The specific plant types they consume are broadly categorized into three main groups, providing a framework for understanding their opportunistic feeding habits.
Primary Dietary Components
The majority of a deer’s diet is drawn from three structural categories of plants: browse, forbs, and mast. Browse consists of the woody parts of plants, including the leaves, buds, and tender new shoots of shrubs and trees such as maple, oak, and certain briars. This material is a year-round staple due to its consistent availability. Deer actively select the youngest, most succulent tips of branches for the highest concentration of digestible energy and protein, as browse is generally lower in nutritional quality compared to other food sources.
Forbs, which are broad-leafed herbaceous plants, including many common weeds and flowering annuals, are highly sought after. These plants, such as clover, alfalfa, and wild lettuce, offer high concentrations of protein and digestible energy, making them a preferred food when actively growing. In agricultural areas, forbs extend to crops like soybeans and cowpeas. These crops are particularly attractive due to their high protein and fat content.
Mast refers to the fruits and nuts of woody plants, categorized as either hard or soft. Hard mast includes nuts like acorns, hickory nuts, and chestnuts, which provide a dense source of fat and carbohydrates for energy storage. Soft mast, such as berries, apples, and persimmons, is rich in simple sugars and vitamins. Deer consume both types of mast rapidly when available to fuel their high-energy demands.
Seasonal Changes in Deer Foraging
The deer’s diet shifts throughout the year to meet changing metabolic demands and utilize new plant growth. Spring and summer are periods of intense growth, requiring a diet high in protein. During this time, bucks are developing antlers, and lactating does significantly increase their energy and protein needs.
Deer focus heavily on forbs and tender new shoots of woody plants, as these are the most protein-rich and digestible options available. Plants like clover, chicory, and forage soybeans are consumed readily. Their high protein content supports antler development and milk production, which can increase a doe’s protein requirement by over 35%. This preference for high-quality forage is sustained until plant maturity causes a decline in nutritional value.
The fall season marks a dietary transition as deer prepare for the breeding season and the scarcity of winter. The focus shifts to energy-dense foods, primarily hard mast like acorns, to build up fat reserves. White oak acorns are often preferred early due to their lower tannin content, while red oak acorns are consumed later.
Winter is characterized by survival feeding, where the diet is dominated by less palatable, lower-quality browse. Deer rely on woody twigs, evergreen foliage, and stored fat reserves accumulated in the fall. During harsh conditions, they may consume plants that were previously avoided because better forage is unavailable.
Plants That Deter Deer
Gardeners and landowners often seek plants that deer tend to avoid, commonly labeled “deer-resistant.” These plants possess specific physical or chemical characteristics that make them unappealing. No plant is truly “deer-proof,” however, when the animals are sufficiently hungry. One common deterrent is the presence of secondary compounds that give plants a bitter taste or are mildly toxic.
Plants with strong, pungent aromas are often bypassed by deer, who rely on their sense of smell to identify palatable food. Herbs and ornamentals with strong scents, such as lavender, catmint, Russian sage, and marigolds, are frequently left untouched. The oils and fragrances in these plants act as a natural repellent.
The texture of a plant’s foliage can also deter deer from browsing. Species with fuzzy or woolly leaves, like lamb’s ear, are generally avoided because deer find the texture disagreeable. Similarly, plants with tough, leathery, or spiny structures, such as some ornamental grasses or spiny shrubs, are less likely to be consumed due to the physical difficulty of eating them.
These preferences can be overridden by environmental stress, particularly during periods of high deer population density or severe winter weather. What a deer avoids under normal conditions may become a food source when survival depends on it. Therefore, “deer-resistant” plants are best understood as lower-preference options that reduce the likelihood of browsing damage.