Ciconia nigra (Linnaeus 1758)

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, often making long sea crossings that other species avoid (8) (9). 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).

The black stork is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in the species should be carefully controlled (4). It is also on Appendix II of the Convention on Migratory Species (CMS), which aims to conserve migratory species throughout their range (13), and is listed under the African-Eurasian Waterbird Agreement (AEWA), which calls upon parties to undertake conservation actions to help protect and conserve bird species that are dependent on wetlands for at least part of their annual cycle (14). Other conservation measures proposed include managing river quality around breeding sites, protecting and managing feeding habitats, protecting large areas of forests, and improving food resources by establishing artificial pools (7) (15). It may also be important to retain large nesting trees during forest management (7) (16), and to limit disturbances during the breeding season, as well as to raise public awareness (16). In recent years, the black stork has been the focus of satellite-tracking projects, namely the African Odyssey and New Odyssey projects, and the 'Flying Over Natura 2000' project (8) (17) (18) (19). These have not only provided more information on the stork's migration patterns, but have also helped raise public awareness both of the black stork and of the 'Natura 2000' protected areas, a network of European protected areas which contain a large proportion of the black stork's breeding sites (12) (17) (18).

The black stork is a large but fairly secretive bird. The black head, upperparts, wings, tail and long neck have a conspicuous green or purple gloss, contrasting with the white belly, undertail and 'armpits'. The long legs and long, straight beak are bright scarlet, and a patch of scarlet skin also surrounds the eye (2) (3) (5) (6). The male and female black stork are similar in appearance, though the male may be slightly larger (2) (3), while the juvenile has slightly browner, duller, less glossy plumage, and a pale olive-green beak and legs (2) (3) (5) (6). The black stork uses a range of calls, including a loud, 'whinnying' call at the nest, hoarse gasping, and beak-clapping (5) (6).

The black stork generally prefers old, undisturbed, open forest and woodland, at elevations of up to 2,000 to 2,500 metres. Foraging occurs in streams, pools, marshes, riverbanks, swampy patches, damp meadows and occasionally in grasslands, but the black stork usually avoids large bodies of water or areas of dense forest (2) (7). Non-breeding birds often overwinter in estuaries and lagoons in South Africa (6) (7), and in rice fields in Europe (10).

The black stork breeds across the Palaearctic, being a widespread summer visitor across much of central and eastern Europe, with a patchier distribution in western Europe and a partly resident population in Spain and Portugal (2) (7). The species overwinters in Africa and also from western Pakistan, through northern India, to southeast and eastern China (2) (7) (8). European birds are thought to choose either a western or an eastern route south into Africa (8) (9). The black stork also breeds in scattered populations across southern Africa, where it may make local, mainly altitudinal movements after breeding (2) (7).

Classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix II of CITES (4).

Although not considered globally threatened, and still having a wide range and large global population, the black stork has generally declined throughout its range, particularly in western Europe (2) (7). The species disappeared from Belgium, Denmark, Sweden and parts of Germany during the last century (2), although it is now reported to be making a comeback in parts of its former range (11). The main threat to the black stork is habitat loss, though deforestation, development, agriculture, draining and conversion of wetlands, and pollution. The use of pesticides is thought to have worsened the situation, and the building of dams and draining of lakes for irrigation and hydroelectric schemes have further reduced the species' habitat (2) (7). For example, the building of the Alqueva dam in Portugal is estimated to have submerged the nesting sites of ten percent of the country's breeding pairs of black storks (12). Hunting and shooting in southern Europe and Asia have also contributed to population declines (2) (7). Black storks are occasionally killed by collision with powerlines and overhead cables (7), and are often disturbed at breeding sites by human activities, including angling, hiking, and the construction and use of new tracks and roads (12).