Icterine Warbler
Hippolais icterina (Linnaeus, 1758)
Order Passeriformes
Family Sylviidae
Conservation status: in Bulgaria: Vulnerable VU C[2(a(i)] + D [1], BDA-III; International: BeC-II.
General distribution. A species with a European type of distribution. The breeding area is mainly in the Western Palearctic, reaching Central Siberia as a thin stripe with separate habitats around the Caspian Sea. In Europe it absent in the British Isles, and in the east it reaches France, Switzerland and the Balkans. A parapatric species of Hippolais polyglotta.
Distribution and abundance in Bulgaria. A breeding summer visitor and passage migrant. In the past it was rare [1]. There are habitats without indications of coordinates in the mountains Pirin [2], Lyulin [3], Konyovitsa Planina [4], Sredna Gora [5], and unconfirmed localities around the town of Svishtov [6] and the city of Varna [7, 8, 9, 10]. At present, the major part of its population is along the Black Sea coast, the Danube [11], in the mountains Strandzha [12] and the Western Balkan range [13, 14]. Because of the insufficient studies in the country, the number of the breeding pairs is estimated through subjective expert opinions, where for the period after 1990 they vary from 50 – 100 [15] to 800 – 1 200 pairs [16]. The breeding population is currently estimated at 300 – 600 pairs
Habitats. Deciduous forests with a rich underbrush, woody plantations, village gardens, shrub associations and wetlands.
Biology. The breeding biology in Bulgaria is understudied. A nest was found at a height of 2,2 m on a young poplar tree. Laying eggs has been registered during the last decade of May [10]. In Central Europe it begins at the beginning of May. The nest is cup-like, built out of dry grasses, roots, moss, intertwined with hairs and fine grasses masked with bark, wool, paper. It has one clutch yearly with 2 – 7 subelliptic, coloured in black spotted pale rose eggs. Incubation lasts for 13 -15 days; the young ones leave the nest after 13 – 14 days [17].
Similar species. The Melodious Warbler (Hippolais polyglotta), the Olivaceous Warbler (Hippolais pallida).
Negative factors. It is sensitive to the destruction of the deciduous forest habitats and their underbrush [17, 18].
Conservation measures taken. Protected according to the Biological Diversity Act. Part of the population inhabits Protected Territories: the Srebarna Reserve [19], the natural parks Strandzha [12] and Vrachanski Balkan [13].
Conservation measures needed. Studying the requirements with respect to the habitats, stopping the destruction of the underbrush in forests with habitats.
References. 1. Patev, 1950; 2. Simeonov, 1986; 3. Paspaleva-Antonova, 1964; 4. Simeonov, Delov, 1989; 5. Petrov, 1981; 6. Harrison, 1933; 7. Reiser, 1894; 8. Jordans, 1940; 9. Mauersberger, 1960; 10. Mountfort, Ferguson – Lees, 1961; 11. Shurulinkov et al., 2005; 12. Milchev, 1994; 13. Georgiev, Milchev, 2000; 14. Nikolov and Vassilev, 2004; 15. Kostadinova, 1997; 16. Nankinov et al., 2004; 17. Snow, Perrins, 1998; 18. Hagemeijer, Blair, 1997; 19. Kambourova, 2005.
Author: Stoyan Ch. Nikolov
