Some varieties, such as mountain ash and holly, have berries that stay on the bush or tree and are available to wildlife in the winter. One of the most popular berries for birds is elderberries. Fifty-one different bird species eat them. Other favorites are sunflowers, preferred by 46 species, and flowering dogwood, favored by 45 bird species. Fruits are also eaten by many different kinds of mammals, including squirrel, fox, deer, bear, skunk, and opossum.
Nuts are really fruits with a dry, hard exterior shell and contain fats and proteins.
Acorns from oak trees are most widely available along with pecans, beechnuts, and walnuts. Squirrels and chipmunks prefer hickory nuts, hazelnuts, black walnuts, and butternuts. Grains and seeds constitute the major food of many species of wildlife. They mature in the summer and fall but some can be found throughout the year. A good example is pigweed.