Atlas of nesting birds in Bulgaria

Grey Heron

(Ardea cinerea)

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

Population size: 2020: 774 – 1 350 pairs (2007: 1 000 – 1 400 pairs)

Distribution pattern

In single or mixed colonies dispersed throughout the country, mainly along the Danube River and the Black Sea coast and the valleys of most major rivers in the plains (the Danubian Plain and the Thracian Plain), and the lower parts of the mountains (mostly in the Fore-Balkans).

Population estimation for the period 2013 – 2020: During the period 2013-2020, the species was found in 172 squares, and its distribution differs significantly from the recorded one before the year 2013. The breeding sites along the Struma and Tundzha Rivers, in the Sofia Field and around the water bodies in the Danubian Plain and the Thracian Plain have not been confirmed, where the species have been registered as breeding before 2013. At the same time, new localities have been found in the Danubian Plain and the Thracian Plain. This dynamics in the distribution is mainly because in the interior of the country the location of the colonies has changed over the years. However, in the Sofia Field and along the valley of the Struma River the colonies have disappeared, they have not relocated. This is mainly due to intensive human activity causing disturbance (extraction of gravel from water bodies, intensive human presence) or loss of breeding and food habitats due to changes in the use or drainage of wetlands, affecting the total population, which has become more variable and decreasing.

Population size in Special Protection Areas of Natura 2000: 351-792 pairs (45% of the population). The highest numbers have been registered in the Special Protection Areas “Studen Kladenets” (37-112 pairs), “Mandra-Poda Complex” (40-93 pairs), “Pyasachnik Reservoir” (47 pairs) and Burgas Lake (0-100 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 smartbirds.org.

Habitats

Breeds in bogs and marshes (water fringe vegetation), in alluvial and riverine forests and brush, sometimes on single or on groups of trees in open agricultural land and artificial landscapes. As an exception breeds on inland cliffs and exposed rocks (a colony of 6–8 pairs breeds near the dam wall of Studen Kladenets).

Trends in population changes for the period 2013-2020

Short-term trend of population size:

Fluctuating

Long-term trend of population size:

Decreasing with non-intermittent fluctuations

Short-term trend of distribution:

With fluctuations

Long-term trend of distribution:

Decreasing with non-intermittent fluctuations

Threats

Drainage of wetlands, changes in the water levels and in the hydrological regime of water bodies during the breeding season, disturbance.

Irina Kostadinova, Petar Shurulinkov, Svilen Chesmedjiev, Vladimir Mladenov