The ruffed grouse (Bonasa umbellus) is a woodland bird found across North America, from the Appalachian Mountains to Alaska. They are known for their ability to thrive in diverse forest habitats, which provide both shelter and sustenance. This adaptability is partly due to their varied diet, which shifts throughout the year based on food availability.
Primary Food Sources
Ruffed grouse are omnivores, consuming a wide array of plant materials and some animal matter. Their diet primarily consists of buds, catkins, twigs, leaves, and fruits from various trees and shrubs. For example, they frequently eat the buds and catkins of aspen, birch, hop-hornbeam, alder, and willow trees. In addition to woody vegetation, they forage for green leaves from ferns, grasses, and other herbaceous plants.
Berries and other fruits are also significant components of their diet, including species like greenbrier, mountain laurel, wild grapes, sumac, and rose hips. Acorns and beechnuts become important food items, especially in regions where oak and beech forests are prevalent. While adult grouse primarily consume plant matter, insects and other small invertebrates provide an important protein source, particularly for young chicks. Adult grouse may supplement their diet with insects.
Seasonal Variations in Diet
The diet of ruffed grouse changes considerably with the seasons, adapting to the availability of different food sources. During winter, when snow covers the ground and other vegetation is scarce, ruffed grouse rely heavily on the dormant flower buds and catkins of deciduous trees. Aspen buds are a preferred winter food, though they also consume buds from birch, willow, and hazel. This woody material provides important sustenance during colder months.
As spring arrives, the diet shifts to include newly emerging green leaves and herbaceous plants. Tender shoots, clover, and early-sprouting flowers become available, offering fresh nutrients after the winter. Throughout the summer, their diet diversifies further to include a wide variety of soft leaves, flowers, and fruits as they ripen. During this period, insects are a more common food source, especially for growing chicks.
In the fall, ruffed grouse incorporate a bounty of various berries, seeds, and nuts into their diet. These provide energy reserves for the upcoming winter.
Foraging Habits
Ruffed grouse employ various methods to obtain their food, adapting their foraging behavior to the type of food available. They primarily forage on the forest floor, using their strong legs and feet to scratch away leaves and debris, uncovering seeds, fallen fruits, and insects. They also browse directly on trees and shrubs, perching on branches to pluck buds, catkins, and leaves. Their ability to climb slender branches allows them to access food high in the canopy.
Ruffed grouse typically feed in frequent, small meals throughout the day, often with peak activity in the early morning and late afternoon. They possess a specialized crop, a widened part of their esophagus, which allows them to temporarily store consumed food. This enables them to feed quickly in potentially exposed areas and then retreat to a safer, more protected location for digestion.
To aid in the digestion of their fibrous diet, ruffed grouse swallow small stones or grit. This grit accumulates in their gizzard, a muscular organ that grinds down food, making nutrients accessible. They often obtain grit from gravel roads or other disturbed soil areas.