I'm going to start series of posts about some of the interesting birds in Bulgaria. I will try to talk about rare birds from my hometown region. The first post will be about the Black Stork (Ciconia nigra). This bird is very,very rare in Bulgaria ,but near Belogradchik there are several lakes where you can see Black Storks. The nearest of them is the Dubrava lake which is 5 kilometers from Belogradchik.
Slightly smaller than the White Stork, the Black Stork is a large bird, 95 to 100 cm (37–39 in) in length with a 145–155 cm (5 ft) wingspan, and weighing around 3 kilograms (6.6 lb). They 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 all black with a purplish green sheen, except for the white lower breast, belly, axillaries and undertail coverts. The breast feathers are long and shaggy forming a ruff which is used in some courtship displays. The bare skin around its eyes is red, as are its red bill and legs. The sexes are identical in appearance, except that males are larger than females on average.
The juvenile resembles the adult in plumage pattern, 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 a paler wings and mantle, longer bill, and white under the wings.
It walks slowly and steadily on the ground. Like all storks, it flies with its neck outstretched. It has a rasping call, but rarely indulges in mutual bill-clattering when adults meet at the nest.
During the summer, the Black Stork is found from Eastern Asia (Siberia and China) west to Central Europe, reaching Estonia in the north, Poland, Lower Saxony and Bavaria in Germany, Czech Republic, Hungary, and Greece in the south, with an outlying population in Spain and Portugal. They are nowhere abundant in these western parts of their distribution, but more densely inhabit the eastern Transcaucasus. A population of Black Stork is also resident in Southern Africa.
Preferring more wooded areas than the better known White Stork, the Black Stork breeds in large marshy wetlands with interspersed coniferous or broadleaved woodlands, but also inhabits hills and mountains with sufficient network of creeks. It does inhabit more areas in the Caspian lowlands.
The Black Stork is a strong migrant, wintering in tropical Africa and India. 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 can be seen going through the Bosporus. They fly approximately 100 to 250 km a day with daily maxima up to 500 km.The storks migrate from the middle of August to the end of September. They return in the middle of March. About 10 percent of the western storks choose the passage Sicily - Cap Bon, Tunisia. The common route goes over Gibraltar. Many birds are fly around the Sahara next to the coast. Most birds are wintering in the wetlands of Nigeria or Mali. The eastern birds take the route Bosphorus-Sinai-Nile to Africa. Birds that summer in Siberia winter in northern and northeastern India. In Southern Africa, Black Storks that nest in the central montane areas perform season winter movements to warmer coastal and subtropical zones.
The Black Stork builds a stick nest high in trees or on cliffs. It nests in Central Europe in April to May, and is a winter visitor to northern India, Nepal east to Myanmar.
Black Stork parents have been known to kill one of their young, generally the smallest, 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. Despite this, this behaviour has not commonly been observed.