However, besides attracting a mate they can also attract predators. That's why the best logs are located in thick young woods that offer protection from hawks and owls and have little debris on the forest floor for mammals to hide behind. The Minnesota DNR has been monitoring grouse populations by performing spring drumming counts for over 50 years. The last population peak was in the fall of 1999 and grouse numbers have since been dropping off a little every spring. These periodic declines appear to be the result of a combination of factors.
Predators often move south from Canada in response to prey shortages north of the border.
Unfavorable weather takes its toll on some birds. Researchers even speculate that grouse's most important winter food source, aspen trees, turn against them by making their buds less edible when populations peak. Ruffed grouse thrive in aspen forests, and need small blocks of different age classes of trees to meet their requirements. Older aspen provides winter food, male aspen flower buds. Hens also nest in mature stands where they can see predators coming.