The black stork, in contrast to the commonly known white stork, is more rarely observed and tends to avoid human contact. It is slightly smaller than the white stork and has black plumage with a metallic, greenish and purple gloss. The belly, undertail coverts and chest are white, which makes this species easy to distinguish from the white stork during flight. Adult black storks have intensely red legs, bill and skin around eyes.
The black stork is a migratory bird, returning from its winter habitat to breed in March and April and staying until September. During the breeding period black storks form monogamous pairs and build their nests in old strong trees, most oftenn oak, pine and alder. The nest is built by both partners. The female lays an average of 3-5 eggs, which are incubated by both parents. Nestlings do not hatch at the same time and in cases of food shortage the youngest and the weakest birds are sometimes killed or pushed out of the nest. Adult black storks produce one brood per year.