The mast (crop of nuts) from American beech provides food for numerous species of animals. Among vertebrates alone, these include ruffed grouse, wild turkeys, raccoons, red/gray foxes, white-tailed deer, rabbits, squirrels, opossums, pheasants, black bears, porcupines, and humans. For lepidopteran caterpillars feeding on American beech, see list of Lepidoptera that feed on beeches. Deer occasionally browse on beech foliage, but it is not a preferred food. Beech nuts were one of the primary foods of the now-extinct passenger pigeon; the clearing of beech and oak forests is pointed to as one of the major factors that may have contributed to the bird's extinction.