by Nick Biemiller | RGS & AWS Forest Conservation Director – Southern Appalachians
The Southern Appalachians are the southernmost extent of the ruffed grouse’s range in the Eastern United States. Appalachian grouse are different than Northern birds, in terms of both the forests they inhabit and the foods they eat. However, across the ruffed grouse’s entire range, the conservation requirement is the same: We need diverse forest habitats that provide an abundance of food options for ruffed grouse and other wildlife species.
Luckily, decades of scientific evidence helps us understand Appalachian grouse and their need for habitat diversity. The Appalachian Grouse Cooperative Research Project (AGCRP) was a multistate cooperative effort initiated in 1996 to investigate the decline of ruffed grouse in the Appalachian region. This project brought together state agencies and university researchers across 12 study sites in 8 states. The AGCRP report highlighted several important conclusions, including the unique food habits and nutrition of Appalachian grouse compared to Northern grouse.
Ruffed grouse diets vary substantially seasonally, annually, regionally and locally. In Northern forests, ruffed grouse are strongly associated with aspen forests, and 46% of their diet consists of aspen flower buds. However, in the Southern Appalachians, aspen trees are a minor component of our forests and an insignificant food source for grouse. Appalachian forests are highly diverse, and Appalachian grouse diets are highly variable.
Summer diets consist of herbaceous (nonwoody) plants, and chicks eat primarily insects during their first weeks. Blueberries and blackberries are also substantial summer food sources. In the fall, Appalachian grouse change their diets and start consuming acorns, beechnuts, greenbrier berries, grapes, sumac fruits, rose hips and hawthorn fruits.
Winter diets are limited, and food sources are often scattered as many of their summer and fall food sources decompose or die back with cold weather and the onset of snow. Research suggests that evergreen leaves (e.g., mountain laurel) are among the poorest-quality foods, but can compose 30% to 45% of a grouse’s diet in January and February. In the spring, green, herbaceous vegetation is important, and the leaves and flowers of early-sprouting plants can compose 90% of the Appalachian grouse diet.
Oak acorns and beechnuts are 26% of the overall Appalachian grouse diet, which is substantially higher than the diets of birds in Northern forests. This is due to the dominance of oak, hickory and mixed hardwood forests in the Appalachian region, and the lack of aspen trees. Oak trees have a “boom-or-bust” pattern of acorn production, whereby there’ll be large numbers of acorns dropped in a given year and barely any for several years after. Good acorn production, known as “mast” years, occur about every 2 to 5 years. The variability of acorn production leads to variability in the Appalachian grouse diet and is another limitation to the availability of high-quality food for them in the region.
Good nutrition is important for healthy grouse populations. Low-quality nutrition can lead to energy deficiency and decreased body fat, which in turn can lead to potential effects on reproduction. For example, studies have found that chick survival is linked to higher fat content in laying hens. Hens with good nutrition (a moderate amount of fat) have higher survival and recruitment of chicks. It all comes down to the availability of the right food sources: healthy forests, healthy food, healthy birds.
To me, all this underscores the need for RGS & AWS’s conservation work, to ensure healthy forests and abundant wildlife. By managing forests to create diverse age classes and structure, we can maintain a diverse range of food options for grouse to eat. By managing specifically for tree species we know are important to grouse diets but limited across the landscape, for example oaks, we can ensure high-quality nutrition. There’s a need for active forest management to create the young forest cover we know ruffed grouse require, but also to maintain diverse food sources that are available in different places throughout the year. This is especially needed in the Southern Appalachians, where we’ve lost 71% of ruffed grouse populations since 1989, and there’s currently only 1.3% young forests across all our National Forest lands. The stakes have never been higher, and we simply must help create more healthy, resilient forests that sustain grouse populations into the future, before it’s too late.
