The Common Grackle forages on the ground, in shallow water, or in shrubs; it may steal food from other birds. It is omnivorous, eating insects, minnows, frogs, eggs, berries, seeds, grain, and even small birds and mice. Grackles at outdoor eating areas often wait eagerly until an unwary bird drops some food. They rush forward and try to grab it, often snatching food out of the beak of another bird.
This bird is omnivorous, which has a diet that includes insects, berries, nuts and seeds, as well as earthworms, snails, and sometimes lizards and frogs. Across seasons and its breeding range, it was found 63% of stomach contents were made of animal matter, the remaining 37% being plant material. During the breeding season, the diet consists primarily of beetles, grasshoppers, and other arthropods, and fruits, nuts and seeds.