STORK

STORK

  

Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family Ciconiidae. They are the only family in the order Ciconiiformes, which was once much larger and held a number of families. 

Storks dwell in many regions and tend to live in drier habitats than the closely related herons, spoonbills and ibises; they also lack the powder down that those groups use to clean off fish slime. Storks have no syrinx and are mute, giving nocall; bill-clattering is an important mode of communication at the nest. Many species are migratory. Most storks eat frogs, fish, insects, earthworms, small birds and smallmammals. There are nineteen living species of storks in six genera.

Various terms are used to refer to groups of storks, two frequently used ones being a muster of storks and a phalanx of storks.

   

Storks tend to use soaring, gliding flight, which conserves energy. Soaring requiresthermal air currents. Ottomar Anschütz's famous 1884 album of photographs of storks inspired the design of Otto Lilienthal's experimental gliders of the late nineteenth century. Storks are heavy, with wide wingspans: the marabou stork, with a wingspan of 3.2 metres (10.5 feet) and weight up to 8 kg (18 lbs), joins theAndean condor in having the widest wingspan of all living land birds.

Their nests are often very large and may be used for many years. Some nests have been known to grow to over two metres (six feet) in diameter and about three metres (ten feet) in depth. Storks were once thought to be monogamous, but this is only partially true. They may change mates after migrations, and may migrate without a mate.

Storks' size, serial monogamy, and faithfulness to an established nesting site contribute to their prominence in mythology and culture.

The centres of stork diversity are in tropical Asia and sub-Saharan Africa, with eight and six breeding species respectively. Just three species are present in the New World: wood stork, maguari stork and jabiru, which is the largest flying bird of the Americas. Two species, white and black stork, reach Europe and western temperate Asia, while one species, Oriental stork, reaches temperate areas of eastern Asia, and one species, black-necked stork, is found in Australasia.

 

A DNA study found that the families Ardeidae, Balaenicipitidae, Scopidae and theThreskiornithidae belong to the Pelecaniformes. This would make Ciconiidae the only group.

Storks were distinct and possibly widespread by the Oligocene. Like most families of aquatic birds, storks seem to have arisen in the Palaeogene, maybe 40–50 million years ago (mya). For the fossil record of living genera, documented since theMiddle Miocene (about 15 mya) at least in some cases, see the genus articles.

Though some storks are highly threatened, no species or subspecies are known to have gone extinct in historic times. A Ciconia bone found in a rock shelter on the island of Réunion was probably of a bird taken there as food by early settlers; no known account mentions the presence of storks on the Mascarene Islands.

   

Within its range the white stork is distinctive when seen on the ground but, when seen at a distance in flight, it can be confused with several other species with similar underwing patterns, such as the yellow-billed stork, great white pelican and Egyptian vulture. The yellow-billed stork is identified by its black tail and a longer, slightly curved, yellow beak. The white stork also tends to be larger than the yellow-billed stork.The great white pelican has short legs which do not extend beyond its tail, and it flies with its neck retracted, keeping its head near to its stocky body, giving it a different flight profile. Pelicans also behave differently, soaring in orderly, synchronised flocks rather than in disorganised groups of individuals as the white stork does. The Egyptian vulture is much smaller, with a long wedge-shaped tail, shorter legs and a small yellow-tinged head on a short neck. The common crane, which can also look black and white in strong light, shows longer legs and a longer neck in flight.