Atlas of nesting birds in Bulgaria

Ferruginous Duck

(Aythya nyroca)

Category of conservation concern (IUCN, 2020) – Near threatened

Population size: 2020: 147 – 466 pairs (2007: 150 – 230 pairs)

Distribution pattern

Grouped and dispersed, mainly along the River Danube and the neighbouring areas of the Danubian Plain, the Black Sea coast, the Thracian Plain and Sofia Field. The most significant breeding sites are Srebarna Lake, Mechka, Orsoya and Pazardzhik Fishponds, Durankulak and Shabla Lakes, and the Dragoman Marsh. Distribution is heavily dependent on the water level of the wetlands in the breeding grounds, some of which dry up during certain years. Often when a particular breeding site disappears, new ones appear nearby. In 2002 after the marshes at Belene Island dried up, breeding pairs were observed at the micro-dams around Svishtov and the town of Belene.

Population estimation for the period 2013 – 2020: During the period 2013-2020, the species was not found in some previous locations, in others there was a decline, but the increase in numbers in key locations due to the redistribution of pairs should be taken into account. The decrease in the numbers is observed mainly in the former fish farms, which are abandoned and the water regime is severely disturbed. The main breeding sites are in wetlands, which have been the focus of restorative activities, to which the species responds quickly and positively. The reduction in the number in Mechka and Orsoya fishponds, as well as in the Tsibarsko Marsh, related to the disturbed water regime and the drying up of part of the territory, is a matter of serious concern. The increased numbers in the area of the Burgas and the Mandra lakes are probably partly due to the redistribution of pairs from the Cherni Vrah fishponds, where the pairs have disappeared due to changes in the management of the fishponds. At the same time, due to the deteriorating environmental conditions in the Srebarna Lake the numbers have declined with nearly 30-40%. 

Population size in Special Protection Areas of Natura 2000: 122-348 pairs (75-83% of the population). The highest numbers have been registered in the Special Protection Areas “Belene Islands Complex” (16-56 pairs), “Srebarna” (20-42 pairs), and “Kalimok Complex” (15-39 pairs).

Big size map

Breeding distribution 2013 – 2020 – The distribution and the estimation of the population size of the species for the period 2013 – 2020 is presented –

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


Breeds on water-fringe vegetation in bogs and marshes, and in non–marine waters (coastal lagoons, standing fresh waters, standing brackish waters).

Trends in population changes for the period 2013-2020

Short-term trend of population size:


Long-term trend of population size:


Short-term trend of distribution:


Long-term trend of distribution:



Changes in the management and the use of artificial wetlands, leading to drainage of parts of the water bodies, accelerated environmental succession, and overgrowing with hydrophilic water loving vegetation. Deteriorated water regime of natural wetlands and the associated environmental succession of vegetation. A potential threat to the main breeding sites is the possible activities for the deepening of the Danube River to improve the navigation on the river, which may lead to deterioration of the water regime of the main breeding sites of the species.

Nikolay Petkov, Svilen Cheshmedzhiev