In deep snow, I've always had my best luck near the outside edge of heavy stands of pine.
Especially good if adjacent to heavy tangles of wild grape or brushy woods where the overhead "cover" permitted by all of the above allows for pockets of lesser snow depth underneath where they can move around a little easier.
Food supply limited this time of year and other good spots are up out of the snow, in the tree tops feeding on buds, aspen being a favorite.
Once or twice I also found some working remaining acorns.
This time of year they tend to flock up, so watch for multiple flushes. Also, look for tell tale tracks in the snow which will indicate birds near by.
Have fun.
