The lack of a substantial accumulation of snow this winter has created hardship for those forms of wildlife that seek shelter from below zero temperatures and gusty winds by embedding themselves in the powdery covering that typically covers the ground at this time of year.
The insulating value of a fairly deep snow pack affords excellent protection against the elements for many creatures small enough to utilize this seasonal layer of material. Among the more sizeable members of the wildlife community that use snow for shelter is the ruffed grouse, well known for plunging head first into a pile of powder in its attempt to completely cover itself with this unlikely natural blanket for an entire day or two.
The ruffed grouse is a ground dwelling bird strongly attracted to woodland edges and mixed forests with periodic breaks in the canopy to permit the growth of pioneer plants. These are the areas that can support poplar trees, hawthorns and other fruit producing shrubs, occasional patches of brambles and the various sun-loving types of vegetation that this game bird depends on for the bulk of its food.
Like a deer, the partridge develops strains of microorganisms in its alimentary canal during the autumn to help in the digestion of the woody matter contained in the buds of various trees that develop in well-lit settings. Additionally, its intestinal tract is reported to expand by as much as 50% to accommodate the increased bulk of fibrous matter needed to sustain it during winter. Although tree buds contain a relatively low concentration of nutritional energy, such material does yield a fairly high amount of heat when it is acted upon by microorganisms. For a grouse, ingesting tree buds is like a person drinking a mug of hot chocolate. While this beverage provides you with a supply of useable nutrients, it also generates a warm internal feeling as this fluid radiates its thermal energy from the inside out.
Throughout the afternoon, a grouse perches among the branches of a poplar, cherry, or apple tree and attempts to consume as much edible material as possible. Like most other birds, the grouse has an elastic pouch, known as a crop, at the end of its throat designed to store a large bulk of material. This enables the grouse to hold almost a fistful of plant material for the gradual release to its digestive system over the span of a long winter night.
Additionally, the grouse will further attempt to insulate itself from the cold by burrowing down into the snow, should there be enough of an accumulation on the ground. When there is about a foot of fluffy powder covering the ground, the grouse is known to plunge from a height of around ten feet directly into the snow. Immediately upon entering the snow, this bird will work its way forward causing snow to fall behind it so that it becomes totally engulfed in this mass of white powdery crystals. The air inside such a cantaloupe-size snow shelter can quickly warm to several degrees above freezing, which makes it highly preferable to the temperature of the air above the snow pack when an arctic air mass becomes entrenched over the region. During prolonged periods of bitter cold, the grouse may elect to remain in place for an entire day or two. Unlike other birds, the partridge does not have to eat every day to remain alive, and when sitting in a snow shelter, it can last for 3 to 4 days without food.
Even though a few areas of the Park have received a fair amount of Lake Effect snow, this snow pack has been rendered unusable for the grouse because of the crust that has developed during thaws and bouts of freezing rain. Grouse have been known to break their neck as they hit a pile of snow that has a solid layer of crust an inch or two below a deposit of powder.
The periods of freezing rain that have impacted the northern sections of the Park on several occasions have also coated the twigs of trees with a layer of ice thick enough to prevent a grouse from easily nipping off the ends of these woody structures and swallowing them. By preventing this bird from accessing it primary source of food for several consecutive days, and having it exposed to bitter cold temperatures and harsh winds, the health of many young and old birds can be jeopardized.
Moderate temperatures with light winds can be tolerated by this hardy game bird for long periods of time when it has access to the buds of trees. While it seems that this winter is going to be one of those lean snow years, the ruffed grouse should be able to do just fine, provided that the polar vortex does not make a reappearance in the area, and that freezing rain is a thing of the past.
Ruffed grouse photo courtesy audoblog.