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Ciconiiformes:
Traditionally, the order Ciconiiformes has included a variety of large, long-legged wading birds with large bills: storks, herons, egrets, ibises, spoonbills, and several others. Ciconiiformes are known from the Late Eocene. Taxonomy:
Following the development of research techniques in molecular biology in the late 20th century, in particular methods for studying DNA-DNA hybridisation, a great deal of new information has surfaced, much of it suggesting that many birds, although looking very different to one another, are in fact more closely related than was previously thought. Accordingly, the radical and influential Sibley-Ahlquist taxonomy greatly enlarged the Ciconiiformes, adding many more families, including most of those usually regarded as belonging to the Sphenisciformes (penguins), Gaviiformes (divers), Podicipediformes (grebes), Procellariiformes (tubenosed seabirds), Charadriiformes, (waders, gulls, terns and auks), Pelecaniformes (pelicans, cormorants, gannets and allies), and the Falconiformes (diurnal birds of prey). The flamingo family, Phoenicopteridae, is related, and is sometimes classed as part of the Ciconiiformes. However, morphological evidence suggests that the traditional Ciconiiformes should be split between two lineages, rather than expanded, although some non-traditional Ciconiiformes may be included in these two lineages. For example, the New World vultures (Cathartidae) are now usually included in the Ciconiiformes. This is not unequivocally accepted, but the vast majority of ornithologists believe it to be accurate based on morphological, behavioral and molecular evidence. Some official bodies, notably the American Ornithologists' Union, have adopted the proposed Sibley-Ahlquist taxonomy almost entirely, however a more common approach worldwide has been to retain the traditional groupings, and modify rather than replace them in the light of new evidence as it comes to hand. The family listing here follows this more conservative practice. Bird taxonomy has been in a state of flux for some years, and it is reasonable to expect that the large differences between different classification schemes will continue to gradually resolve theselves as more evidence becomes available.
Physical Characters:
Ciconiiformes have only a single pair of sternotracheal muscles in the syrinx; 16-20 cervical vertebrae; are diastataxic (the fifth secondary feather is absent, but fifth secondary covert is present); the feet are not webbed; the middle claw is laterally expanded, (pectinate in some families); intestinal ceca present, nearly always very small.
Ciconiiformes primarily occupy fresh water or terrestrial habitat, they are not filter feeders, and mostly feed on fish, crustaceans, insects, and carrion. They do not swim for food, and the northerly species migrate. They are strong flyers with broad wings. Most nest in trees although some build nests in swamps or on the ground. The young are altricial. Most species are generally colonial but the use of sound is uncommon. Social communication is by displays and rituals. |
