CICONIIFORM

(order Ciconiiformes), any member of five or six families of long-legged, long-necked, long-footed storklike birds adapted to wading in shallow water. The order comprises herons and bitterns (Ardeidae), shoebills (sole species of the Balaenicipitidae), hammerheads (sole species of the Scopidae), storks (Ciconiidae), ibis and spoonbills (Threskiornithidae). Some authorities also include flamingos (Phoenicopteridae). Birds of this order tend to be large, and many species possess spectacular powers of flight, occasionally migrating across the lengths of two continents. They are also noted for their graceful shape and movement. They are found all over the world except in the polar regions, though most species are concentrated in warm climates. With some exceptions, the preferred habitat is near an expanse of freshwater. For the most part they eat other animals, usually fish, but they also prey upon small mammals, birds, reptiles, amphibians, and a number of invertebrates, including mollusks, crustaceans, insects, and worms. Some species, such as the marabou, are known to be both predators and carrion eaters, while the cattle egret feeds on insects. The flamingos are exceptions to many general rules applied to other ciconiiforms. Their chief food is minute algae, which they capture by flushing water through fine, hairlike plates in their mandibles, rather like the way certain whales use baleen to catch small crustaceans. Most ciconiiforms are silent birds, making few cries, though some storks make a noisy clatter by snapping their mandibles together. The large bittern makes a booming cry in spring. Many species are markedly gregarious, often forming flocks numbering hundreds of thousands. Indeed, lesser flamingos have been known to gather in assemblies of more than 1,000,000 on a single African lake. Even those ciconiiforms which, because of their feeding habits, must separate during the day commonly reassemble at dusk to fly to a communal roost. Most species breed in large, often enormous, colonies that may include a mixture of species. Most species are arboreal nesters and the nest sites are often at great height. The white storks nest in a variety of sites and quite often in close association with humans. The nests are usually composed of loosely assembled sticks and stems. Though they can run rapidly when the need arises, most ciconiiforms move with a deliberate, long-legged gait. Their wings are broad and strong for flying. Many of the larger storks take advantage of thermal air currents to rise to great heights and perform prodigious feats of soaring. In direct flight, flocks are often seen in a V-formation. The plumage of herons tends toward blue, gray, and white patterns, while storks often have contrasting areas of white and black. A few ciconiiform birds are brilliantly plumed, notably the flamingos and the scarlet ibis. During the mating season herons develop long plumes which hang from the head, neck, breast, or back. In many species the colour of the bills, irises of the eyes, legs, and bare patches of skin become brighter, usually redder, during the period of sexual display, and there may even be an intensification of the colour in moments of excitement. Roseate spoonbill (Ajaia ajaja) Lesser flamingo (Phoeniconaias minor) (order Ciconiiformes), any member of the five or six families of storklike birds: herons and bitterns (Ardeidae), the shoebill (sole species of the Balaenicipitidae), the hammerhead (sole species of the Scopidae), typical storks and wood storks (Ciconiidae), ibis and spoonbills (Threskiornithidae; see photograph), and, according to some authorities, flamingos (Phoenicopteridae; see photograph). Most are of substantial size, long-legged and long-necked, and adapted for wading. They are widely distributed, often abundant, and apt to be conspicuous in their open habitats or in the air. Many are notably graceful in form and movement, and some have spectacular powers of flight. Additional reading James Hancock and James Kushlan, The Herons Handbook (1984), covers all aspects of the species. Walter J. Bock, A Generic Review of the Family Ardeidae (Aves), American Museum Novitates, no. 1779 (1956), discusses the taxonomy of the herons. Frank A. Lowe, The Heron (1954), gives the natural history of the European grey heron (Ardea cinerea). Andrew J. Meyerriecks, Comparative Breeding Behavior of Four Species of North American Herons (1960), provides a valuable contribution to the knowledge of behaviour in the group. R.P. Allen, The Flamingos: Their Life History and Survival (1956), surveys the family. Leslie Brown, The Mystery of the Flamingos, new and expanded ed. (1973), delineates the natural history of the East African species. Sir A. Landsborough Thomson The Editors of the Encyclopdia Britannica