Great Cormorant

Category of conservation concern (IUCN, 2020) – Least Concern

Population size: 2020: 2239 – 5281 pairs (2007: 2000–2800 pairs)

Distribution pattern

Dispersed in North Bulgaria, Eastern Stara Planina (Golyama and Luda Kamchiya River valleys) and in the area of Burgas. The colonies are clearly grouped along the Danube River (mainly on the islands) and in some parts of the Danubian Plain (near bigger rivers and dams). Most of the breeding sites near the Burgas area are located in the Vaya Lake, Poda and Komlushka lowland. 

DPopulation estimation for the period 2013 – 2020: uring the period 2013-2020, the species was not found in eleven squares, where it was recorded as breeding before 2013. In some of these cases, the colonies have moved to neighbouring squares (for example at Studen Kladenets Dam). Some of the colonies in the neighbouring squares along the Danube River were mapped in 2013, but they are located in Romania, so they are not registered. The colonies on the island of Byalata Prast near the village of Srebarna, on the island of Vardim, the one in the old riverbed near the village of Orehovitsa, Pleven District, the Mandra dam and the eastern part of Burgas Lake have disappeared. New colonies have been mapped in a total of eleven 10X10 km squares – in the Kalimok fishponds, near Primorsko, the Vaya Protected Area, the northern shores of the Burgas Lake, on dikes in the oxidation ditches of Lukoil Neftochim, on the quay opposite the Shabla lighthouse, in the Iskar Gorge, around the Yastrebino, Batak, Tsankov Kamak and Pyasachnik dams.

Population size in Special Protection Areas of Natura 2000: 1729 – 4338 pairs (81 % of the population). The highest numbers have been registered in the Special Protection Areas: “Mandra-Poda Complex” (834-2660 pairs), “Ibisha Island” (300-700 pairs), “Strandzha” (240 pairs), “Burgas Lake” (20-180 pairs) and “Durankulak Lake” (120- 170 pairs).

Comparative distribution of the species compared to the first breeding birds atlas (Iankov, 2007): Breeding locality until 2007 | Breeding locality until 2007, confirmed after 2015 – | New breeding locality after 2015. – The breeding localities after 2015 are identified on a base of raw data from smartbirds.org.

Habitats

Mainly in alluvial and riverine forests and brush near running waters of large rivers or dams, coastal lakes with standing fresh waters, including standing brackish waters. Breeds in marshes and lagoons.

Trends in population changes for the period 2013-2020

Threats

Poaching, drainage of wetlands, loss of habitats and other reasons, logging in the area of the colonies, changes in the water level of the water bodies during the breeding season, disturbance in the breeding and roosting habitats, collisions with power lines, entanglement in fishing nets and other fishing gear.

Petar Shurulinkov, Vladimir Mladenov, Girgina Daskalova, Ralitsa Georgieva