The primary wild rabbit species in Illinois is the Eastern Cottontail, Sylvilagus floridanus. Its adaptable diet is dictated largely by the dramatic seasonal shifts in the Midwest. These herbivores consume a wide variety of plant material, transitioning from succulent, high-moisture greens in the warmer months to woody, high-fiber sustenance when vegetation dies back. The cottontail’s ability to change its foraging behavior is necessary for survival across the state’s diverse landscapes, which include farmlands and suburban yards. Understanding their natural diet provides insight into their ecological role and their common interactions with human environments.
The Primary Diet During Growing Seasons
During the spring, summer, and early autumn, the Eastern Cottontail’s diet consists mainly of tender, herbaceous plants that are readily available across Illinois meadows, fields, and lawns. Rabbits are grazers, meaning they primarily seek out low-growing vegetation, and this fresh material is characterized by a high water and protein content. Native and introduced grasses constitute a substantial portion of this warm-weather foraging, including species like bluegrass, fescue, and crabgrass.
The animals also actively consume broadleaf weeds, which are highly preferred food sources due to their nutritional density and palatability. Common weeds such as clover, plantain, chickweed, and dandelion are frequently targeted, providing the cottontails with necessary vitamins and minerals. When foraging near agricultural areas, they will readily feed on crops like alfalfa, garden peas, and various beans.
The green, leafy diet is rich in water, helping the rabbit meet hydration needs without a separate water source. Cottontails are hindgut fermenters, adapted to process high-fiber diets through a specialized process called coprophagy. They re-ingest soft fecal pellets, known as cecotropes, to absorb maximum nutrients that were not initially digested.
Winter Survival: Foraging for Woody Plants
The diet shifts dramatically with the onset of cold Illinois winters when herbaceous plants wither or become covered by snow, forcing cottontails to seek out different food sources. Their winter survival depends on browsing woody plant material, which is much lower in moisture and significantly higher in cellulose. This material includes the bark, twigs, and buds of various shrubs and trees.
Specific woody plants often targeted during winter include the bark of young fruit trees, especially apple and cherry, as well as ornamental shrubs in suburban settings. They also forage on the stems and buds of native plants like sumac, hawthorn, willow, and blackberry canes. The gnawing action required to consume the tough bark and twigs also serves the biological function of wearing down their continuously growing incisor teeth.
The high-cellulose diet requires a digestive strategy relying heavily on the microbial breakdown of tough fibers in the cecum. Cottontails feed mostly at night during the winter months to avoid predators while consuming this less-nutritious, high-volume food. The resulting energy deficit is often managed by relying on fat reserves built up during the more abundant growing seasons.
Identifying Toxic and Unsuitable Foods
While wild rabbits are adept at identifying suitable forage, they may encounter certain plants and human foods that are toxic or nutritionally unsuitable. Many common garden and ornamental plants contain compounds poisonous to cottontails. These include plants grown from bulbs, such as tulips, daffodils, and hyacinths, as well as foxglove, yew, and members of the nightshade family.
The leaves of rhubarb and the green parts of a potato plant also contain toxins that can be harmful if consumed. Wild rabbits avoid these plants, but they may sample them out of curiosity or extreme hunger, particularly in heavily landscaped areas. Many human food scraps are inappropriate for a rabbit’s delicate digestive system.
Processed grains, corn, and sugary fruits can disrupt the sensitive bacterial balance in the rabbit’s gut, leading to severe digestive issues. While often associated with rabbits, common iceberg lettuce and root vegetables like carrots offer little nutritional value and excessive water content compared to their natural forage. A healthy wild diet must consist primarily of high-fiber plant matter, not low-nutrient vegetables or high-sugar items.