What do deer eat, anyway?
In summer, deer eat leafy green plants, such as wildflowers and tree leaves. They are not cows, and do not eat grass. In winter, deer browse on the outer twigs of shrubs and trees -- about one cubic foot (30 litres) of twigs per day. Twigs, unfortunately, are mostly wood, and no matter how much they consume, they become malnourished. They depend on fat reserves to survive. If the winter is too long and severe, some of them die of starvation.