Mourning doves eat almost exclusively seeds, which make up more than 99% of their diet. Rarely, they will eat snails or insects. Mourning doves generally eat enough to fill their crops and then fly away to digest while resting. They often swallow grit such as fine gravel or sand to assist with digestion. The species usually forages on the ground, walking but not hopping. At bird feeders, mourning doves are attracted to one of the largest ranges of seed types of any North American bird, with a preference for rapeseed, corn, millet, safflower, and sunflower seeds. Mourning doves do not dig or scratch for seeds, though they will push aside ground litter; instead they eat what is readily visible. They will sometimes perch on plants and eat from there.