|In "Kruger National Park, "South Africa|
|Range of C. nigra Breeding range Year-round range Wintering range|
The black stork (Ciconia nigra) is a large bird in the "stork family Ciconiidae. Its "plumage is mainly black, with white underparts. Adults have long red legs and long pointed red beaks, measuring on average 95–100 cm (37–39 in) from beak tip to end of tail with a 145–155 cm (57–61 in) wingspan. A widespread, but uncommon, species, the black stork breeds in the warmer parts of Europe (predominantly in central and eastern regions), across temperate Asia and Southern Africa. It is a long-distance "migrant, with European populations wintering in tropical Sub-Saharan Africa, and Asian populations in the "Indian subcontinent. When migrating between Europe and Africa, it avoids crossing the "Mediterranean Sea and detours via the "Levant in the east or the "Strait of Gibraltar in the west, because the air "thermals on which it depends do not form over water. The South African population does not migrate and breeds in the winter rather than summer.
A shy and wary species, unlike the closely related "white stork, the black stork is seen singly or in pairs, usually in marshy areas, rivers or inland waters. It feeds on "amphibians, small "fish and "insects. Breeding pairs usually construct nests on large boulders, under overhanging ledges or on large forest trees—a wide variety of both "deciduous and "evergreen—which can be seen from long distances. The female lays two to five "eggs, with white shells having a greyish hue. The black stork is considered to be a "species of least concern by the "International Union for Conservation of Nature, as the wide range, large population and low apparent rate of decline mean that it does not meet the threshold for "vulnerable status. Despite its large range, it is nowhere abundant, and appears to be declining in many parts of its range. Various conservation measures have been taken for the black storks, including the Conservation Action Plan for African black storks by "Wetlands International, which focuses on the wintering conditions of the birds which breed in Europe. It is covered under the "African-Eurasian Waterbird Agreement and the "Convention on International Trade in Endangered Species of Wild Fauna and Flora.
English naturalist "Francis Willughby wrote about the black stork in the 17th century, having seen one in Frankfurt, naming it Ciconia nigra. It was one of the many "species originally described by Swedish "zoologist "Carl Linnaeus in the landmark 1758 "10th edition of his "Systema Naturae, where it was given the binomial name of Ardea nigra. It was moved to the new "genus "Ciconia by French "zoologist "Mathurin Jacques Brisson two years later. Both the genus and the "specific names are "Latin; Ciconia is "stork" and niger/-gra is "black". The word stork is derived from the "Old English word storc, thought to be related to the "Old High German storah, meaning "stork", and the Old English stearc, meaning "stiff".
The black stork is a member of the genus "Ciconia, or typical storks, a group of seven "extant species, characterised by straight bills and mainly black and white "plumage. The black stork was long thought to be most closely related to the "white stork (C. ciconia). However, genetic analysis via "DNA–DNA hybridization and mitochondrial "cytochrome b DNA by Beth Slikas in 1997 found that it was "basal (an early offhoot) in the genus Ciconia. "Fossil remains have been recovered from "Miocene beds "Rusinga and "Maboko Islands in Kenya, which are indistinguishable from the white and black storks.
Slightly smaller than the white stork, the black stork is a large bird, measuring 95–100 cm (37–39 in) in length with a 145–155 cm (57–61 in) wingspan, and weighing around 3 kg (6.6 lb). It can stand as tall as 102 cm (40 in). Like all storks, it has long legs, a long neck and a long, straight, pointed "beak. The plumage is black with a purplish green sheen, except for the white lower breast, belly, armpits, axillaries and "undertail coverts. The breast feathers are long and shaggy, forming a ruff which is used in some courtship displays. The black stork has brown "iris, and bare skin around its red eyes. The sexes are identical in appearance, except that males are larger than females on average. "Moulting takes place in spring, with the iridescent sheen brighter in new plumage.
The "juvenile resembles the adult in plumage, but the areas corresponding to the adult black feathers are browner and less glossy. The scapulars, wing and upper tail coverts have pale tips. The legs, bill and bare skin around the eyes are greyish green. It may be confused with the juvenile "yellow-billed stork, but the latter has paler wings and mantle, longer bill and white under the wings. The black stork walks slowly and steadily on the ground. Like all storks, it flies with its neck outstretched.
During the summer, the black stork is found from Eastern Asia ("Siberia and northern China) west to "Central Europe, reaching Estonia in the north, Poland, "Lower Saxony and "Bavaria in Germany, the Czech Republic, Hungary, Italy and Greece in the south, with an outlying population in the central-southwest region of the Iberian Peninsula ("Extremadura and surrounding provinces of Spain, plus Portugal). It is not abundant in these western parts of its distribution, but more densely inhabits the eastern "Transcaucasus. It winters into the "Indian subcontinent, particularly India where it ranges from "Punjab south to "Karnataka, and Africa. An isolated population exists in "Southern Africa, where the species is more numerous in the east, in eastern South Africa and Mozambique, and is also found in Zimbabwe, Swaziland, Botswana and less commonly Namibia.
The black stork is a rare vagrant to the "British Isles, turning up in the warmer months—particularly in spring—generally in the south and east. Sightings have become more common since the 1970s as its breeding range moves northwards. It has been recorded in Scotland six times between 1946 and 1983, including from Shetland, Orkney and the Highlands, as well as the Scottish Borders (Peebles). After disappearing from Belgium before the onset of the 20th century, it has returned to breed in the "Belgian Ardennes, Luxembourg and "Burgundy, France, by 2000. It appears to be increasing in numbers in Spain and Portugal, where the population was estimated at 405 to 483 pairs in 2006.
It is an occasional visitor to Sri Lanka, and was first recorded in western Myanmar in 1998. In the "Korean Peninsula, the black stork is a uncommon summer visitor, no longer breeding in the south since 1966. Birds have been seen in the northeast but it is not known if they breed there. Similarly it has been seen in the summer in Afghanistan, but is unknown if it breeds there.
The black stork prefers more wooded areas than the better known white stork, and breeds in large marshy "wetlands with interspersed "coniferous or "broadleaved "woodlands, but also inhabits hills and mountains with sufficient networks of "creeks. It usually inhabits ponds, rivers, edges of lakes, estuaries and other freshwater wetlands. The black stork does inhabit more agricultural areas in the "Caspian lowlands, but even here it avoids close contact with people.
The black stork is a "migrant, wintering in tropical Africa and Asia, although certain populations of black storks are sedentary or dispersive. Migration takes place from early August to October, with a major exodus in September. Some of the "Iberian populations, and also those in southern Africa, are essentially non-migratory, though they may wander freely in the non-breeding areas. A broad-winged soaring bird, the black stork is assisted by thermals of hot air for long distance flight, although are less dependent on them than the white stork. Since thermals only form over land, storks, together with large "raptors, must cross the "Mediterranean at the narrowest points, and many black storks travel south going through the "Bosphorus, as well as the Sinai and Gibraltar. The trip is around 5,667 km (3,521 mi) via the western route and 7,000 km (4,300 mi) via the eastern route, with satellite tracking yielding an average travel time of 37 and 80 days respectively The western route goes over the "Rock of Gibraltar of over the "Bay of Gibraltar, generally on a southwesterly track that takes them to the central part of the Straight, from where they reach Morocco. Many birds fly around the "Sahara next to the coast. About 10% of the western storks choose the passage "Sicily – "Cap Bon, Tunisia, which might be due to the frequent flapping flights compared to those of the white storks.
Spain contains several important areas—"Monfragüe National Park, "Sierra de Gredos Regional Park, National Hunting Reserve in Cíjara, Natural Park of the Sierra Hornachuelos and "Doñana National Park—where black storks stopover on the western migration route. Further south, "Lake Faguibine in Mali is another stopover point. However, it has been affected by drought in recent years. Pesticide use has threatened birdlife in Doñana.
Most of the black storks that summer in Europe migrate to Africa, with those from western Germany and points west heading south via the Iberian Peninsula and the rest via Turkey and the Levant. Those flying via Spain spend winter in the "Falémé River basin of eastern Senegal, Guinea, southern Mauritania, Ivory Coast, Sierra Leone and western and central Mali, while those flying via the Sinai end up in northern Ethiopia, the "Kotto River basin in the Central African Republic, the Mbokou river basin in Chad and northeastern Nigeria. Black storks summering in "western Asia, migrate to "northern and "northeastern India. Those summering further east in eastern Russia and China winter mainly in "southern China, although occasionally further south, in Myanmar, "northern Thailand, Hong Kong and Laos.
The black stork has a wider range of calls than the white stork, its main call being a chee leee, which sounds like a loud inhalation. It makes a hissing call as a warning or threat. Displaying males produce a long series of wheezy raptor-like squealing calls rising to a crescendo and then falling. It rarely indulges in mutual bill-clattering when adults meet at the nest. Adults will do so when angered or as part of mating ritual. The young clatter their bills when aroused.
The up-down display is used for a number of interactions with other members of the species. Here a stork positions its body horizontally and quickly bobs its head up from down-facing to around 30 degrees above horizontal and back again, and displaying the white segments of its plumage prominently, and this is repeated several times. The display is used as a greeting between birds, and—more vigorously—as a "threat display. Threat displays are uncommonly seen due to the solitary nature of the species.
The black stork mainly eats "fish, although it may feed on "amphibians, "insects, small "reptiles, "snails, "crabs, "mammals and "birds. Its insect diet primarily includes "water beetles and their "larvae, and "earthworms. It also forages on "newts, "shrews, small "rodents and "molluscs. Among the fish species, the diet mostly constitutes mostly small "cyprinids, "pikes, roaches, "eels, budds, "perches, "burbots, "sicklebacks and muddy "loaches ("Misgurnus and "Cobitis). It has been observed, although rarely, that the black stork also forages with both wings raised in an open canopy.
Foraging for food takes place mostly in fresh water, though the black stork may look for food on dry land at times. The black stork wades patiently and slowly in shallow water, often alone or in a small group if food is plentiful. It has been observed shading the water with its wings while hunting. In India, it often forages in mixed species flocks with the white stork, "woolly-necked stork (Ciconia episcopus), "demoiselle crane (Grus virgo) and "bar-headed goose (Anser indicus). The black stork also follows large mammals such as deer and livestock, presumably to eat the invertebrates and small animals flushed by the latter's presence.
The black stork nests in the northern hemisphere spring over April and May. In southern Africa, breeding takes place over autumn and winter, possibly to take advantage of abundant water prey rendered easier to catch as the rivers dry up and recede—from April and May in Zimbabwe, Botswana and northern South Africa, and as late as July further south.
The nest is large, constructed from sticks and twigs, and sometimes also large branches, and are at an elevation of 4–25 m (13–82 ft). Away from human disturbance, the black stork prefers to construct its nest in forest trees with large canopies where the nest can be built far from the main trunk. For the most part, deciduous trees are chosen for nesting sites, though conifers are used as well. A 2003 field study in Estonia found that the black stork preferred oak ("Quercus robur), European aspen ("Populus tremula), and to a lesser extent Scots pine ("Pinus sylvestris), and ignored Norway spruce ("Picea abies), in part due to the canopy structure of the trees. Trees with nests averaged around 25.6 ± 5.2 m high and had a "diameter at breast height of 66 ± 20 cm. Furthermore, 90% of the trees chosen were at least 80 years old, highlighting the importance of conserving old-growth forests. A 2004 field study of nesting sites in Dadia-Lefkimi-Soufli National Park in north-eastern Greece found that it preferred the Calabrian pine ("Pinus brutia), which had large side branches that allowed it to build the nest away from the trunk, as well as black pine ("Pinus nigra) and to a lesser extent oak ("Quercus cerris). The storks chose the largest trees in an area, generally on steeper ground and near streams. Trees chosen were on average over 90 years old. In the Iberian peninsula it nests in pine and cork oak ("Quercus suber).
In steeply mountainous areas such as parts of Spain, South Africa and the "Carpathian Mountains it nests on cliffs, on large boulders, in caves and under overhanging ledges. The black stork nests solitarily, which are usually at least 1 km (0.6 mi) apart, even where the species are numerous. Although newly constructed nests may be significantly smaller, older nests can be 1–2 m (3.3–6.6 ft) in diameter. In southern Africa, the black stork may occupy the nests of other bird species such as "hamerkop (Scopus umbretta) or "Verreaux's eagle (Aquila verreauxi) and commonly reuse them in successive years. They are repaired with earth and grass, and lined with leaves, "moss, grass, animal-fur, paper, clay and rags.
The eggs are usually laid in late April. In a clutch, there are two to five, or rarely even six large oval eggs, with white shells having a greyish hue, which get soiled during incubation. They can be 64–70 mm (2.5–2.8 in) long and 50–53 mm (2.0–2.1 in) wide, averaging about 68 mm (2.7 in) in length and 52 mm (2.0 in) in width. The eggs are laid with an interval of two days. Hatching is asynchronous, and takes place at the end of May. "Incubation takes 32 to 38 days, with both sexes sharing duties, which commences after the first or second egg is laid. The young start flying by the end of July. "Fledging takes 60 to 71 days, after which the young joins the adults at their feeding grounds. However, for another 2 weeks, the young continue to return to the nest, to be fed and to roost at night.
Until the nestlings are 2 to 3 weeks old, at least one adult remains in the nest to protect the eggs or the young. Both parents feed the young by regurgitating onto the floor of the nest. Black stork parents have been known to kill one of their fledglings, generally the weakest, in times of food shortage to reduce brood size and hence increase the chance of survival of the remaining nestlings. Stork nestlings do not attack each other, and their parents' method of feeding them (disgorging large amounts of food at once) means that stronger siblings cannot outcompete weaker ones for food directly, hence parental infanticide is an efficient way of reducing brood size. This behaviour has only rarely been observed in the species, although the shyness of the species and difficulties in studying its nesting habits mean that it might not be an uncommon phenomenon.
Black storks host more than 12 species of "helminth, with Cathaemasia hians and Dicheilonema ciconiae reported to be the most dominant. Juvenile black storks host fewer helminth species overall, but carry higher parasite loads than adults do. A new species of "Corynebacterium—C. ciconiae—has been isolated from the trachea of healthy black storks, and is thought to be part of the natural flora of the species.
Since 1998, the black stork has been rated as a species of "least concern on the "IUCN Red List of Endangered Species. This is because it has a large range—more than 20,000 km2 (7700 mi2)—and because its population is thought not to have declined by 30% over ten years or three generations and thus is not a rapid enough decline to warrant a "vulnerable rating. However, the state of the population overall is not known, and although it is widespread, it is not abundant anywhere. Black stork numbers have declined for many years in western Europe, and the species has already been extirpated from "Scandinavia. The population in India—a major wintering ground—is declining. Previously a regular winter visitor to the "Mai Po Marshes, it is now seldom seen there, and appears to be in decline in China overall. Its habitat is changing rapidly in much of eastern Europe and Asia. Various conservation measures have been taken, including "Wetlands International's Conservation Action Plan for African black storks, which focuses on improving the wintering conditions of the birds which breed in Europe. It is protected by the "Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) and the "Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Hunters threaten the black stork in some countries of southern Europe and Asia, such as "Pakistan, and breeding populations may have been eliminated there. The black stork vanished from the "Ticino River valley in northern Italy, with hunting a likely contributor. In 2005, black storks were released into the Parco Lombardo del Ticino in an attempt to re-establish the species there.
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