For an animal to use food as fuel, it must digest the food - break it down small enough to be absorbed into the bloodstream - and get rid of the waste products. A bird's gut looks much like your own, but there are some differences. Many seed and grain-eating birds have a crop connected to the esophagus. The expandable crop allows birds to quickly gather and store a large amount of food, then retreat to safety to digest it. bird has two stomachs (we have one) to digest its food in record time. In four hours, a Spur-winged Goose can digest the same meal that it takes a rabbit 24 hours to digest. In the upper stomach, the proventriculus, food is broken down with digestive enzymes.The lower stomach, the ventriculus, or gizzard, is a tough, muscular organ which crushes and grinds up the food, just like our teeth do for us. Remember a bird has no teeth, so it swallows food whole. Birds that eat plants and seeds have more powerful gizzards than meat and fish eaters. Many birds swallow grit or gravel to help the gizzard break down food.