Deer are adaptable herbivores that consume a wide variety of plant materials. Their food choices are primarily driven by availability and their changing nutritional requirements throughout the year. This adaptability allows them to thrive in diverse habitats. A deer’s digestive system, particularly its four-chambered stomach, is specialized to process fibrous plant matter, yet it also requires a diet rich in easily digestible nutrients.
Deer’s Natural Diet Preferences
In their natural habitats, deer primarily favor “browse,” which includes tender leaves, buds, and twigs from woody shrubs and trees like oak, maple, and dogwood. These woody plants provide essential nutrients, especially when other food sources are scarce. Deer also value “forbs,” herbaceous, broad-leaved plants like clover and wildflowers. Forbs are generally more digestible and nutrient-rich, making them a preferred food source, especially in spring and summer.
Another component of a deer’s natural diet is “mast,” encompassing both hard and soft varieties. Hard mast includes acorns, hickory nuts, and beechnuts, rich in fats and carbohydrates for concentrated energy. Soft mast, such as berries, apples, and plums, offers sugars and vitamins. Fungi and lichens are also consumed when available. These natural foods are selected for their palatability and the energy and protein they provide for growth and overall health.
How Deer Diets Change Seasonally
A deer’s diet shifts with the changing seasons, adapting to food availability and physiological needs. In spring, as new growth emerges, deer seek fresh, tender vegetation, including young leaves and protein-rich forbs. This helps them recover from winter and supports antler growth and fawn development. This period requires high-quality, easily digestible forage to rebuild body mass. During summer, their diet expands to include lush green vegetation, more forbs, and soft mast like berries and fruits. These foods provide energy and nutrients for continued growth and lactation in does.
Fall is a time when deer focus on high-calorie foods to build fat reserves for winter and the rut. Hard mast, such as acorns and nuts, becomes important due to its high fat and carbohydrate content. Deer consume these energy-dense foods. As winter arrives and other food sources become scarce, deer rely more heavily on woody browse, buds, and evergreen leaves. Their digestive systems adjust to process these higher-fiber, lower-quality foods, allowing them to conserve energy during colder temperatures.
What Deer Enjoy in Gardens and Farms
Deer frequently venture into human-cultivated areas, where gardens and farms offer readily available, palatable food sources. Agricultural crops are a significant attraction, with corn and soybeans being favorites due to their high caloric and protein content. Deer consume corn ears as they develop and forage for leftover grains after harvest. Soybeans, rich in protein, are also heavily browsed, especially their green leaves during summer. Alfalfa and clover are other common farm crops deer readily consume.
In residential gardens, deer favor a range of ornamental and vegetable plants. Hostas and daylilies are often among the first consumed due to their tender foliage. Roses, despite thorns, are also appealing, as are impatiens and various fruit tree saplings. Vegetable gardens provide preferred items, including beans, peas, lettuce, carrots, and the tops of beets and broccoli. These cultivated plants are attractive for their taste, accessibility, and concentrated nutrients, often leading to conflicts with homeowners and farmers.
Harmful Foods for Deer
While deer have a broad diet, certain foods, particularly those provided by humans, can be detrimental. Processed human foods, such as bread, pastries, and snacks, offer little nutritional value and disrupt a deer’s specialized digestive system. Their four-chambered stomach, especially the rumen, contains microbes adapted to break down fibrous plant material. Large quantities of high-starch, low-fiber foods can upset this microbial balance.
Corn, while consumed naturally in smaller quantities, becomes problematic when fed in large amounts, especially during winter. A sudden influx can lead to acidosis, where excessive lactic acid is produced in the rumen, lowering its pH and killing beneficial bacteria. This causes bloating, diarrhea, and in severe cases, death, as the deer can no longer digest food, effectively starving with a full stomach. Moldy hay or grains also introduce harmful toxins. Additionally, feeding deer can lead to unnatural congregation, increasing disease transmission and habituating them to human presence, which may result in negative interactions.