Ducks are aquatic birds, mostly smaller than their relatives like swans and geese, and may be found in both fresh water and sea water. Females are known as duck and males as drake. Drakes have extravagant plumage, but that is moulted in summer to give a more female-like appearance, the "eclipse" plumage. Most of then have a wide flat beak adapted for dredging. The rich green sheen and bright yellow beak of the male is in sharp contrast to its drab female counterpart, with her orange beak and brown plumage. They feed on grasses, aquatic plants, fish, insects, small amphibians, worms, and small mollusks. Diving ducks and sea ducks forage deep underwater while Dabbling ducks feed on the surface of water or on land. Dabbling ducks have in their beaks special plates called lamellae. These tiny rows of plates along the inside of the beak let them filter water out of the side of their beaks and keep food inside. Diving ducks are heavier than dabbling ducks, and therefore have more difficulty taking off to fly. Many species of ducks are temporarily flightless while moulting i.e after routine shedding of old feathers; they seek out protected habitat with good food supplies during this period. They are hunted for food, sports and farming.