Seagulls feed on coastal insects, mollusks, crustaceans and worms and grubs in cultivated land; They also prey on small fish on the shore and pick up leftovers discarded on the shore and on ships. Some large seagulls prey on eggs and young birds of other birds (including their own kind).
Seagulls are the most common seabirds. In the coastal areas, seaports and fishing grounds rich in fish and shrimp, flocks of seagulls float on the water, swimming, foraging and flying at low altitude, and like to cluster in food-rich waters.
In addition to eating fish, shrimp, crabs and shellfish, seagulls also like to pick up leftovers discarded by people on board, so seagulls are nicknamed "harbour cleaners". Ports, docks, bays and ships are almost frequent visitors.