I was doing a bit more research into winter time grouse foods when I came across this: Winter Food Habitats of Ruffed Grouse in Young Aspen Stands. This paper is based on finding from a 1972-1973 study of 10-15 year old clear cuts in Oneida County, Minnesota.
The researchers found that the top ruffed grouse foods were Aspen bud and Hazel catkins. The grouse also were also feeding heavily on a species of ferns, as well as on wintergreen and goldenthread.
