Common Merganser

(Mergus merganser)

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

Population size: 2020: 2-7 pairs (2007: 2-5 pairs)

Distribution pattern

For the Common Merganser, a northern species, Bulgaria is on the border of its southernmost breeding range. Breeding sites have been registered in dams in the Rhodope Mountain – Borovitsa, Studen Kladenets and Kardzhali. It is possible to be observed in other high mountain water bodies in the Rila-Rhodope Massif and Stara Planina.

Population estimation for the period 2013 – 2020: During the period 2013-2020, the species was found in five squares along the valley of the Borovitsa River and the Arda River.

Population size in Special Protection Areas of Natura 2000: 2-5 pairs (71-100% of the population). The highest numbers have been registered in the “Dobrostan” SPA (1-3 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

Breads in cavities and holes in cliffs and exposed rocks near deep standing freshwater bodies, with large open water surfaces with no water fringe vegetation. 

Trends in population changes for the period 2013-2020

Threats

Poaching and trapping in fishing nets, disturbance 

Volen Arkumarev