Avocet
Recurvirostra avosetta (Linnaeus, 1758)
Order Charadriiformes
Family Recurvirostridae
Conservation status: in Bulgaria: Endangered EN=B[1(a+b(ii+iii)) +2(a+b(ii))] + C[2a(ii)], BDA-II, III; International: BeC-II, BoC-II, ECS-Spec 4/3w,, BD-I.
General distribution. A cosmopolitan species with a scattered distribution. In Europe from Sweden to Spain, in the east to the Black Sea basin. It winters in Africa and Southern Asia, Western Europe and the Balkan peninsula.
Distribution and abundance in Bulgaria. In the past a regular breeding summer visitor in the Burgas lakes and incidentally in Alepu Marsh, along the valleys of the Danube and the Iskar [1 - 16]. In the recent years the breeding population has been concentrated in the lakes around Burgas (mainly Atanasovsko Ezero lake), with total numbers about 250-800 pairs [17, 18]. It breeds less often in Shablenska Tuzla lake [19], the Beloslav-Varna Lake Complex [20], Durankulak Lake [21] and incidentally within the country and along the Danube valley [18, 22]. During migrations it is most numerous in Atanasovsko Ezero lake [17], rarely within the country [24]. It winters regularly in Atanasovsko Ezero lake [17, 25], its numbers reaching up to 1 500 individuals in warmer winters.
Habitats. Shore salty, brackish or freshwater basins, salted terrains, sand bars, fish farms, artificial water basins.
Biology. A colonial species. The nests are situated amongst halophytic vegetation, along open dikes, sand bars and shores. It lays 3-4 eggs. It feeds on water invertebrate animals, small fish and vegetable remains.
Similar species. None.
Negative factors. Abrupt changes of the water level in the places of breeding, disturbance during repair activities of the dikes in the lakes Atanasovsko and Pomoriysko, destruction of the clutches and the nests with newly hatched birds by ground predators, pollution of the waters.
Conservation measures taken. Protected according to the Biological Diversity Act. Included in the Red Data Book of Bulgaria (1985). Ramsar Sites, Natura 2000 Protected Territories and Zones are the lakes Atanasovsko, Poda, Vaya, Shabla and Durankulak, for which there are Management Plans. Dike islands in Atanasovsko Ezero lake were built. Monitoring is being carried out.
Conservation measures needed. Working out management plans for the lakes Pomoriysko, Uzungeren and Shablenska Tuzla. Making stable alluvial islands in the lakes Atanasovsko and Pomoriysko; regulation of the numbers of the ground predators in them.
References. 1. Alleon, 1886; 2. Hristovich, 1890; 3. Reiser, 1894; 4. Varbanov, 1912; 5. Boetticher, 1927; 6. Harrison, 1933; 7. Varbanov, 1934; 8. Jordans, 1940; 9. Pateff, 1948; 10. Prostov, 1955; 11. Mounfort & Fergusson-Lees, 1961; 12. Ballat, 1962; 13. Prostov, 1964; 14. Konigstedt, Robel, 1977; 15. Nankinov, Darakchiev, 1978; 16. Michev, 1985; 17. Dimitrov et al., 2005; 18. Dimitrov, Profirov, 2006, in press; 19. Ivanov, 1998; 20. Dimitrova, Petkov, 1986; 21. Nankinov et al., 1996; 22. Nankinov et al., 1997; 23. Roberts, 1981; 24. Nankinov et al. 1998; 25. Michev, Profirov, 2003.
Author: Milko Dimitrov
