Classification The phylogenomic study by Hackett et al found that the families Ardeidae (Herons, Egrets, Bitterns), Balaenicipitidae (Shoebill, not shown), Scopidae (Hamerkop) and Threskiornithidae (Ibises, Spoonbills), which used to be members of the Ciconiiforme order, share instead a common ancestor with Pelicans (see the Pelicaniformes order). For this reason, the Ciconiiforme order is now restricted to the 19 living species of storks.

Storks are large, long-legged, long-necked wading birds with long, stout bills. They have no syrinx or voice box and are mute, giving no call; bill-clattering is an important mode of stork communication at the nest.

Many species are migratory. Storks tend to use soaring, gliding flight, holding neck straight out. Soaring requires thermal air currents. Storks are heavy, with wide wingspans: the Marabou Stork, with a wingspan of 10.5 ft , joins the Andean Condor in having the widest (but not the longest) wingspan of all living land birds. Only the Wandering and Royal albatrosses are longer (11.4 ft ).

Most storks eat frogs, fish, insects, earthworms, small birds and small mammals. Marabous are scavengers whose heavy bill is a fearsome weapon. White stork nests are often very large and may be used for many years, individual white storks returning to same nest year after year. 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.

Hackett SJ et al (2008): Phylogenomic Studies of Birds