In biology-speak, deer need to browse what's known as early successional herbaceous growth, the small woody plants that grow after bare earth is first covered by grasses and forbs. During wet, mild weather deer eat grasses, forbs, or any other easily digestible green growth available, but they need young browse to survive Saskatchewan winters or Arizona summers. Farm crops supplement this natural diet, but farms don't exist everywhere in North America, and crops aren't available year-round. For long-term survival, deer need tender browse, such as honeysuckle and shadbush in the East, snowberry and big sagebrush in the Rockies, manzanita and mountain mahogany in the Southwest, or salas and bearberry along the West Coast. And they need varied browse, because certain plants provide the most nutrition at specific times of year.