Western Orphean Warbler
Sylvia hortensis (Gmelin, 1789)
Order Passeriformes
Family Sylviidae
Conservation status: in Bulgaria: Vulnerable VU [B1a, c(i, ii)], BDA-III; International: BeC-II, BoC-II, ECS-Spec 3.
General distribution. A Mediterranean species breeding in Southern Europe, Turkey, the Southern Caucasus Mountains, Central Asia and Northern Africa.
Distribution and abundance in Bulgaria. It is found only in the southernmost parts of the country: the valleys of the rivers Struma (in the north to the city of Blagoevgrad) and Mesta, the feet of the mountains Southern Pirin, Slavyanka, Ograzhden and Malashevska Planina, in the Eastern Rhodopes, Sakar, the Derventski Vazvisheniya (hills), the western slopes of Strandzha, in the areas of the cities of Sliven and Burgas and at cape Emine [1-20]. The density of the breeding population varies from 0,31 to 1,6 pairs/10ha. In separate years it may be absent in some of the habitats [17, 19, 20]. For the 1998-2000 period, an increase in the numbers was observed [21].
Habitats. Pseudomaquises and dry-loving formations similar to them of thorn, hornbeam, oak, juniper, etc., and among the thick shrubs overgrown with blackberry along the borders of extensively used moderately-sized areas of vineyards, orchards, vegetable gardens, etc.
Biology. The pairs occupy the breeding territory at the beginning of April. The nest is placed on thorn, Pyrus amygdaliformis, or among the thicket of blackberry. Laying the eggs is from the end of April to the end of May. Newly hatched ones are observed from the middle of May - until the middle of June. It feeds on insects and fruits [4, 7, 10, 11, 14, 17].
Similar species. None.
Negative factors. There are no data about factors with a direct effect. It is possible for an influence on the population to be exerted by the increased use of insecticides. The restrictedness of the characteristic biotope is a prerequisite for vulnerability. In the future, a definite negative effect would be played by the destruction of the typical habitats of the species restricted in area and distribution.
Conservation measures taken. Protected according to the Biological Diversity Act. Some of the habitats are within protected territories: the Tisata Reserve, Natural Phenomenon Cape Emine, Natural Phenomenon Malkiya Kozhuh. Most of the typical sites are not protected.
Conservation measures needed. Additional studies are necessary, related to the distribution, numbers, ecology and biology of the species. It is necessary that those sites where the highest density was registered be declared protected territories: in the mountains Sakar, Derventski Vazvisheniya (hills), Southern Pirin, Ograzhden and Malashevska Planina and of the whole Kresna Gorge.
References. 1. Patev, 1950; 2. Prostov, 1963; 3. Donchev, 1964; 4. Donchev, 1965; 5. Simeonov, 1970; 6. Simeonov, 1974; 7. Vatev, Simeonov, 1978; 8. Petrov, 1981; 9. Prostov, Smilova, 1983; 10. Nanev, 1988; 11. Spiridonov, Simeonov, 1988; 12. Iankov, 1991; 13. Stoyanov et al., 2001; 14. Donchev, 1981; 15. Dontschev, 1989; 16. Robel, Konigstedt, 1978; 17. Milchev, Kovachev, 2000; 18. Stoychev et al., 2004; 19. Nikolov, Spasov, 2005; 20. Karaivanov, 2005; 21. BirdLife International, 2004.
Authors: Bozhidar Ivanov, Petar Shurulinkov
