The black stork feeds mainly on fish, although it may also take insects, amphibians, snails, crabs, and small reptiles, mammals and birds (2) (7). Most foraging takes place in shallow water, where the black stork stalks its prey, catching it with a quick stab of the beak (2). The black stork is capable of long periods of sustained flight, and may undertake migrations of up to 7,000 kilometres or more, often making long sea crossings that other species avoid (12) (13). The migration patterns and routes taken by the species have been well studied (12) (14), with European populations thought to take either a short western route south into Africa, through the Strait of Gibraltar, or a longer eastern route through the Strait of Bosphorus (12) (13). However, an unknown percentage travel only as far as the Iberian Peninsula (9) and Israel (10) (11). The Siberian population are known to migrate towards south-western Asia (Afghanistan, Kazakhstan, Pakistan and south-west China), to the northern Indian subcontinent (15), while birds from Mongolia migrate through China to South East Asia. Southern African populations, in contrast, make mainly local, altitudinal movements after breeding (2) (7).
Although it may travel in small groups during migration, and may form groups of up to 30 individuals on its wintering grounds, the black stork is a solitary nester (2) (7). Breeding usually starts in spring in the Palaearctic and in South Africa, and mostly in the cool dry season further north in Africa (2). The nest is a large structure, up to 1.5 metres in diameter, and is usually built high in a large forest tree, or on a cliff. The structure is built with sticks and is lined with moss, grass and leaves, cemented together with earth. The same nest may be used year after year, or the breeding pair may take over the nest of another species, such as a large bird of prey or a hamerkop (Scopus umbretta) (2) (7). An average of three to four eggs are laid, and hatch after an incubation period of between 32 and 38 days. The chicks fledge at 63 to 71 days, and may take up to three years to reach maturity. The black stork is reported to live to at least 18 years old in the wild and up to 31 years in captivity (2).