Great Bittern

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

Population size: 2020: 52 – 88 pairs (2007: 20 – 70 pairs)

Distribution pattern

A rare breeding species with a small population. Breeds all over the country in various water bodies overgrown with reeds or rushes. Most of the established breeding sites are in the Upper Thracian Plain, the Tundzha Plain and along the Danube River, but the highest density of the species is registered in the Dragoman Marsh and the Aldomirovo Marsh in Sofia District. Along the Black Sea coast, it is very uncommon as a breeding species. In some years with unfavourable conditions (low or too high water levels) has not inhabited some of the localities. 

Population estimation for the period 2013 – 2020: During the period 2013-2020, the species has not been found in 22 squares, where it was recorded before the year 2013. Deterioration of the habitats explain their disappearance, but in most such squares, the species has been found with low degree of reliability for breeding. New breeding sites have been established in 10 squares.

Population size in Special Protection Areas of Natura 2000: 30 – 51 current males (57% of the population). A large part of the population, near various reed-covered reservoirs and fishponds, in the Thracian Plain is not included in the Natura-2000 network. The highest numbers are found in the Special Protection Areas “Rayanovtsi” (8 – 15 males), “Kalimok Complex” (3 – 8 males) and “Srebarna” (2 – 4 males).

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

Breeds in marshes and non-marine waters, in water fringe vegetation, giving preference to extensive wet reed beds, partly submerged (up to 30 сm) and with surface not less than 20 ha. Of crucial importance is the existence of standing fresh waters or standing brackish waters, at the periphery of which is their forage habitat.

Trends in population changes for the period 2013-2020

Threats

Drainage of wetlands, changes in the water level of water bodies during the breeding season, disturbance from anglers, poaching.

Petar Shurulinkov, Svilen Chesmedjiev, Vladimir Mladenov