Little Tern

(Sternula albifrons)

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

Population size: 2020: 100 – 442 pairs (2007: 100 – 220 pairs)

Distribution pattern

Grouped mainly along the Black Sea coast (the Burgas wetlands). With unclear status on the Northern Black Sea coast – in the area of Shabla and Durankulak lakes and on the Danube River (mainly in the area of the Belene Island). Isolated breeding site near the Tsibar marsh.

During the period 2013-2020, the species was established in 22 ETRC 10×10 km. Significant increase in the area of the habitat of the species was registered along the Danube River. In the studied period, the localities around Shabla and Durankulak lakes have not been confirmed, but the species could still be breeding there periodically.

Population estimation for the period 2013 – 2020: The number of species in the country varies greatly annually. Very often in different years, the species move to different squares looking for the best breeding conditions. Stable increase was noted in the Burgas lakes and especially along the Danube River. The lower waters of the Danube River, which is becoming a tendency, visibly has a positive effect on the species, creating many suitable for breeding sand islands.

Population size in Special Protection Areas of Natura 2000: 100-220 pairs 49.77-100% of the population. All significant and regular breeding sites of the species are located on the territory of the Natura 2000 network. The largest number of breeding habitats outside the Natura 2000 network are found along the Danube River. The highest numbers have been registered in the Special Protection Areas: “Pomorie Lake” (40-210 pairs), “Atanasovsko Lake” (10-75 pairs), and “Belene Islands Complex” (0-70 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

Breeds on the banks of coastal lagoons – salty and hypersaline lakes (saltpans), standing fresh waters, standing brackish waters and running waters (on sandbars along the River Danube), as well as on coastal sand dunes and sand beaches, rarely near marshes and in grassy water fringe vegetation. The breeding season is exceptionally extended and is consistent with the optimal breeding conditions and sufficient amount of food to feed the chicks. During poor environmental breeding conditions, the species can be present in the breeding habitats throughout the season without attempting to breed. Often breeds in mixed colonies with other Plover subspecies.

Trends in population changes for the period 2013-2020

Threats

Predation threatening eggs and chicks in breeding colonies. Extreme climatic events because of global climate change. Destruction of nests and chicks due to technical activities in the production and extraction of salt. Sharp changes in the water level of rivers. Destruction of breeding habitats due to extraction of aggregates from riverbeds. Deepening of riverbeds and using concrete to stabilise riverbeds.

Vladimir Mladenov, Ralitsa Georgieva, Petar Shurulinkov