A buck is defined as an adult male deer, typically referring to the white-tailed deer or the mule deer. These animals are ruminant herbivores, meaning they possess a specialized four-chambered stomach system adapted to digesting tough plant matter. Unlike grazers, which consume large quantities of grasses, bucks are highly selective feeders that choose high-quality, easily digestible forage. Their diet is constantly shifting, driven by the changing availability of vegetation and their own fluctuating metabolic demands throughout the year.
Primary Food Categories: Browse, Forbs, and Mast
The natural diet of a buck is composed of three fundamental categories of vegetation, which together provide the necessary nutrients for survival and growth.
Browse
Browse consists of the tender shoots, twigs, leaves, and buds of woody plants, shrubs, and small trees that are within reach. Examples include the leaves of red maple, various species of greenbrier, and the persistent leaves of hollies.
Forbs
Forbs are broad-leafed, non-woody plants that are not grasses. This category includes wildflowers, weeds, and common agricultural plants like clover and alfalfa. Forbs are generally lower in fiber and significantly higher in digestible protein and moisture content than browse, making them a premium food source, particularly during the growing season.
Mast
The third major component of the diet is mast, which is divided into hard mast and soft mast. Hard mast refers to the fruits of woody plants with hard shells, such as acorns from oak trees and nuts from hickory trees, which are packed with energy. Soft mast includes fleshy fruits and berries, such as wild grapes, apples, persimmons, and blackberries.
The Role of Seasonal Availability
The buck’s reliance on these three food types is heavily governed by the four distinct seasons.
Spring
As winter recedes, spring brings the first flush of new, green growth, prompting a shift toward high-moisture forbs. The new shoots and leaves are highly succulent and easily digestible, allowing the buck to quickly regain body mass lost during the lean winter months. This period is important for maximizing protein intake to fuel muscle recovery and the initial stages of antler development.
Summer
The summer diet continues to center on lush forbs and the early availability of soft mast, such as various berries. During these warmer months, the rapidly growing antlers demand a continuous supply of high-quality forage. The high water content in forbs and soft mast also helps the animal meet its hydration needs during hot weather.
Fall
As temperatures cool, the dietary focus shifts dramatically in the fall to energy storage for the impending rut and the cold season. This is when hard mast, particularly acorns, becomes a major component of the diet due to its high concentration of carbohydrates and fats. Successfully building a thick layer of fat during this time is directly linked to a buck’s ability to endure the energy-intensive rut and survive the following winter.
Winter
Winter presents the greatest challenge, as most high-quality food sources are either dormant or covered by snow. The buck enters a survival mode, relying on stored fat reserves built up in the fall and shifting its diet to persistent browse. This includes the dormant twigs, buds, and evergreen leaves of plants like greenbriers and hollies, which remain available above the snow line. During periods of deep snow or extreme cold, the buck limits movement to conserve energy, subsisting on the less nutritious, high-fiber woody material until the spring green-up.
Nutritional Needs Driving Food Selection
Protein and Minerals
Protein and minerals are the primary drivers of food selection during the spring and summer. Rapid body growth and the annual cycle of antler development demand a high-protein diet. The newly growing antler is composed of a protein matrix onto which minerals are deposited for hardening. To support this, minerals like calcium and phosphorus are often mobilized directly from the buck’s skeletal system. Dietary intake of these minerals is then used to replenish the skeletal reserves, which is why a year-round supply of mineral-rich forage is important.
Carbohydrates and Fats
Conversely, carbohydrates and fats become the most important nutritional components in the fall. These macronutrients are necessary for building the substantial energy reserves required to sustain the buck through the breeding season, or rut, when feeding activity is drastically reduced. After the rut, these fat reserves provide the energy needed for basic metabolic functions and warmth to ensure survival through the scarcity of winter.