In Bulgaria it is also called golyama dyavolitsa (big devil), karabatak, karabulak or lorna, and in the past baklan or batlan. This species belongs to to the cormorant (Phalacrocoracidae) family and in Bulgaria there are two more members of this family.
Great Cormorant is a relatively large bird. The body length reaches up to 100 cm with a wingspan of 160 cm. In adult birds sexual dimorphism is not observed. Their whole plumage is black with green metallic sheen. On the sides of the head and neck show up many white feathers, whose number increases during the breeding season. During this period a large oval white spot appears on their groin. Their underchin and frenulum are yellow and the iris is emerald green, feet are black. Young birds are brown with different-sized whitish spots on their abdomen and chest.
The Great Cormorant is a fish-eating bird. Hunt singly or in small groups as it dives and can stay under water more than a minute. Often the cormorant becomes a victim at fishing ponds because people believed that it causes great damage and pursue it relentlessly. When its feathers get wet, you can see this large bird resting or drying with outstretched wings on the trees or poles of power lines. The Great Cormorant flies with slow, powerful strokes of the wings and their flocks are wedged.
The beginning of the cormorant's breeding season is at the end of February, when the birds occupy colonies and begin marital preparation. The Great Cormorant nests in single or mixed colonies with herons and various other birds. Single-lying nests are exception. These birds prefer to build their nests in oak, white hybrid poplar or willow. In early May, the female lays 3-5 eggs, bluish in colour, with rough limestone deposits. Both birds take part in incubation and rearing of the youngsters.
In Bulgaria breed between 1600 and 2800 pairs, as the colonies are most numerous along the Danube riverbank. The species nests also in the Eastern Balkan Mountains in the rivers valleys of Great and Luda Kamchia; around Burgas city by the lakes Vaya, Mandra, Protected area Poda and reservoir Studen kladenets.