Winter Grouse Survival Depends on Food and Cover

Examining food and cover necessary for winter grouse survival.

In northern Wisconsin, winter regrouping of ruffed grouse starts to take place toward the end of October and the first part of November. The grouse group together this time of the year, not for security or for a social gathering, but because there is good food and cover in a single location. When in a group, grouse remain individualists. Each will flush on their own accord when pressured. It is the availability of high quality habitat and food that has brought them together.

When there is more than three or four inches of snow on the ground grouse tend to fly more than walk (unless the snow has a crust). However, food sources still need to be interspersed within protective cover and close to where they roost, loaf and sun themselves. During this time of year, conserving energy is the main goal of ruffed grouse. At around 20 degrees Fahrenheit or below a grouse needs to speed up its metabolism in order to stay warm.

During the winter, grouse will typically eat two times a day. When available, the food of choice is the male aspen bud. The female aspen bud is nutrient deficient and is not a food of choice for grouse.

Grouse have been observed taking more than 47 bites per minute in the branches of male aspen trees. Thus, they can fill their crops with buds within 15-20 minutes. The stout twigs that produce these buds will typically have five to eight buds on a twig, thus allowing the bird to feed very quickly without much movement which is critical as the birds are more vulnerable to predators while feeding.

If it is bitter cold in the morning, a grouse may feed only once during the day. The grouse will remain in its snow burrow, conserving energy before a late afternoon feeding. Grouse can often be seen feeding in aspen tree as the sun sets when they are silhouetted in the afterglow.

The aspen trees they feed in are typically over 25 years of age. However, I have seen grouse feeding in younger stands of aspen when more mature aspen was not available.

Hazel brush combines food and cover.

Depending on the part of the country you live, you may be familiar with hazel brush, beaked hazelnut or even American hazelnut. Regardless of name, this shrub-type bush offers both food and cover for grouse.

Hazel will often be interspersed in aspen or in solid thickets of hazel brush. The grouse will often feed on the hazel catkins in late fall and early winter before switching over to male aspen buds. The birds can move on the ground with thick brush overhead and easily slip away from or flush in front of any potential predators.

Hazel offers excellent protection to feeding grouse. The larger the patch of hazel brush, the more secure a grouse feels to move freely about.

Roosting and snow burrows play an important role in winter grouse survival.

In winter, roosting sites can be near the base of a tree, typically conifers, or a grouping of conifers. When grouse roost in or under conifers, they seek out clumps of 15-20 year old trees that will provide both thermal cover and protection from predators. As trees grow, the spacing between the limbs becomes greater, thus allowing predators to perch in these trees and swoop in on unsuspecting grouse. A cluster of young pines is better suited than one single pine for thermal protection and safety.

Typically, in the Midwest when there is very little snow on the ground a grouse will use clusters of balsam fir, hemlock, cedar or even spruce. However, when there is 10-12 inches of snow on the ground grouse prefer to burrow under the snow while roosting.

Grouse will dive into the soft snow at an angle and burrow into the snow, moving away from the opening sometimes up to 15 or 20 feet. When in the burrow, the grouse will have 3 to 4 inches of snow cover above.

The major advantage of a snow burrow, besides concealment, is the constant temperature within the burrow. When a grouse is in a burrow the temperature typically does not drop below 20 degrees Fahrenheit which conserves energy and maintains its reserves.

When snow levels are not sufficient for snow roosting, grouse are limited to thermal cover usually provided by conifer trees. A grouse may make a bowl type depression in shallower snow that will serve as its roost site. In either case, grouse are more vulnerable when they are unable to snow roost.