Any of about 26 species of medium-sized wading birds (subfamily Threskiornithinae) of the same family as the spoonbills. Ibises are found in all warm regions except on South Pacific islands. They wade in shallow lagoons, lakes, bays, and marshes, using their slender down-curved bills to feed on small fishes and soft mollusks. Species range from 22 to 30 in. (55 to 75 cm) long. Ibises fly with neck and legs extended, alternately flapping and sailing. They usually breed in vast colonies.