Deer are grazing herbivores with a primarily plant-based diet. While opportunistic, they exhibit distinct preferences for certain plant types. Understanding their consumption in natural and human-influenced areas offers insight into their behavior and ecological role.
Preferred Natural Foods
In wild habitats, deer primarily consume browse, forbs, and mast. Browse, the tender shoots, twigs, and leaves of woody plants, forms a substantial part of their diet, especially in colder months. Examples include sumac, maple, oak, and dogwood, providing essential nutrients and fiber.
Forbs are broad-leafed herbaceous plants like wildflowers and legumes, favored for high nutritional content. Clover, alfalfa, and various wildflowers are sought after, particularly in spring and summer when lush and available. They offer rich protein and nutrients vital for growth and reproduction.
Mast refers to fruits and nuts from trees and shrubs, divided into soft and hard mast. Soft mast includes berries (blackberry, blueberry, wild grape), apples, and persimmons. Hard mast, like acorns, hickory, and beechnuts, is a prized fall food source. These crops provide concentrated energy for building fat reserves before winter.
Common Agricultural and Garden Choices
In human-cultivated areas, deer’s opportunistic habits extend to agricultural crops and garden plants. Many vegetables are palatable, leading to consumption in gardens and farms. Favorites include lettuce, beans, peas, and corn, providing accessible nutrition.
Fruit trees and berry bushes attract deer due to high sugar content. Apples, peaches, and berries (raspberries, strawberries) are frequently consumed. Deer may also browse their leaves and young shoots.
Ornamental plants, planted for aesthetic appeal, also become a food source. Hostas, daylilies, impatiens, and some roses are commonly targeted in residential landscapes. Their availability draws deer closer to human dwellings.
Seasonal Changes in Diet
A deer’s diet changes yearly, driven by food availability and seasonal nutritional needs. In spring, new growth means lush, protein-rich forbs and tender browse, supporting rapid growth and post-winter recovery. Summer continues this with abundant green vegetation, maximizing nutrient intake.
In autumn, the focus shifts to mast crops (acorns, nuts), providing crucial energy and fat. These high-calorie foods help deer build reserves for winter. As winter progresses and fresh vegetation is scarce, deer rely on woody browse (twigs, buds). They may also turn to residual agricultural crops if natural foods are depleted or snow-covered.
Foods to Never Feed Deer
Certain foods are harmful and should never be offered. Human processed foods (bread, pastries, chips, candy) cause severe digestive upset. Deer digestive systems aren’t adapted to refined sugars, artificial ingredients, or high starch.
Large quantities of corn can be detrimental. While deer eat corn, excessive amounts cause fatal acidosis. Corn ferments rapidly in their rumen, creating an acidic environment that destroys beneficial gut bacteria and leads to systemic health problems.
Pet food, moldy hay, and spoiled grains pose health risks, introducing bacteria, toxins, or nutritional imbalances. Providing unsuitable foods compromises deer health and natural foraging behaviors.
Preferred Natural Foods
In their natural environments, deer consume a diverse range of plant materials, primarily classified as browse, forbs, and mast. Browse consists of the leaves, buds, and tender twigs of woody plants, forming a significant portion of their diet, especially when other food sources are scarce. Examples of preferred browse include the foliage and young stems of trees like maple, oak, and sumac.
Forbs are broad-leafed herbaceous plants, including wildflowers and various “weeds,” which are highly digestible and rich in nutrients. Deer favor forbs such as clover, alfalfa, ragweed, and goldenrod, especially during warmer months when these plants are abundant and provide essential protein and energy. These plants are particularly important for deer recovering from winter, bucks growing antlers, and does preparing for fawning.
Mast refers to the fruits and nuts produced by trees and shrubs, categorized as soft mast and hard mast. Soft mast includes berries like blackberries, blueberries, and wild grapes, as well as fruits such as apples and persimmons. Hard mast, like acorns from oak trees, hickory nuts, and beechnuts, are concentrated sources of carbohydrates and fats, crucial for deer to build fat reserves, especially in the fall before winter.
Common Agricultural and Garden Choices
When deer encounter human-cultivated areas, their diet readily expands to include a variety of agricultural crops and garden plants. Many common vegetables are highly appealing to deer, such as lettuce, beans, peas, and corn. These cultivated plants offer easily accessible and often nutrient-dense food sources.
Fruit trees and berry bushes are also frequently targeted by deer due to their sweet, energy-rich produce. Apples, peaches, and various berries are sought after by deer in orchards and gardens. Beyond the fruit, deer may also browse on the leaves and young shoots of these plants.
Ornamental plants, which are grown for their aesthetic value, can also attract deer. Species like hostas, daylilies, and certain roses are commonly consumed by deer in residential landscapes. The presence of these palatable plants can draw deer into closer proximity to human dwellings, sometimes leading to garden damage.
Seasonal Changes in Diet
A deer’s diet shifts significantly throughout the year, adapting to seasonal availability of food and their changing metabolic needs. In spring, as new vegetation emerges, deer primarily consume lush, protein-rich forbs and tender new browse to support recovery from winter and initial growth. This period is crucial for muscle rebuilding in bucks and for pregnant does.
During summer, deer continue to consume a high volume of green forage, including forbs and browse, ensuring they meet their nutritional demands for antler development and fawn growth. As autumn approaches, their diet transitions to include more mast crops, such as acorns and other nuts, which provide concentrated energy to build fat reserves for the coming winter. In winter, when fresh vegetation is scarce or covered by snow, deer rely heavily on woody browse, consuming the buds and twigs of trees and shrubs. They may also forage on residual agricultural crops like standing corn or soybeans if available.
Foods to Never Feed Deer
Certain foods are harmful or inappropriate for deer and should not be offered. Human processed foods, including bread, pastries, and candy, can cause severe digestive upset. Deer digestive systems are specialized for plant matter and are not equipped to handle the refined sugars, high starch content, or artificial ingredients found in these items.
While deer may consume corn, providing it in large quantities can be detrimental. Excessive corn can lead to acidosis, a condition where rapid fermentation in their rumen creates an acidic environment that can be fatal. This is because their digestive microbes need time to adapt to new food sources. Pet food and moldy hay also pose risks, potentially introducing harmful bacteria, toxins, or nutritional imbalances that can negatively impact deer health.