Pygmy Owl
Glaucidium passerinum (L., 1758)
Order Strigiformes
Family Strigidae
Conservation status: in Bulgaria: Endangered species EN [D], BDA-II, III; International: BeC-II, CITES-II, BD-I.
General distribution. A siberian-Canadian species with a breeding area from Norway to Sakhalin island with a width of up to 1 000 km, Northern America; it also breeds in some mountains in Western, Central and Southeastern Europe, where there is a relict population of post-glacial times [1].
Distribution and abundance in Bulgaria. Resident, in the past understudied and known only by 2 individuals from Rila [2, 3]. Between 1975 and 1983 it was found several times in the Tsarichina Reserve [4], and in 1977 in Vitosha [5]. At present it inhabits the Central Balkans National Park (the reserves Tsarichina, Steneto and Boatin) [6, 7, 8, 9], the Rila Monastery Natural Park, Northern Rila, the Rila National Park [10, 11, 12, 13], the Western Rhodopes – Beglika [Z. Spiridonov, unpubl. data], Batashka Planina [13], Dabrash [P. Shurulinkov, A. Ralev, unpubl. data], Southern Pirin [13] and Slavyanka [14]. The numbers in the places found so far are about 100 breeding pairs. According to other estimates, they are 30-120 pairs [15].
Habitats. Old coniferous, beech, fir-coniferous and riverside forests between 1 000 and 1 850 m.
Biology. Monogamous, the pair is preserved for years. It breeds in hollows of woodpeckers with a diameter of 45-55 mm, also in houses. It lays 4-6 eggs, mostly from the middle of April until the middle of May, it incubates for 28-29 days; the young ones stay in the nest for 29-32 days [16]. During the breeding period, the diurnal activity is 18 hours, it sleeps during the night [17, 18]. The territories of the pairs in the Central Balkans National Park and the Rila Monastery Natural Park are 50-150 ha each, they are permanent and are marked by voice all the year round, most actively during the breeding period and the autumn; 6,5 and 15 km of transects 3, and, respectively, 6 pairs were registered (G. Spiridonov, unpubl. data). In Central Europe outside the breeding period the food consists of birds (mainly songbirds) – about 60%, mouse-like rodents and shrews [19]. It gathers reserves for the winter; up to 97 victims have been found in hollows [16].
Similar species. None.
Negative factors. Felling the old coniferous and beech forests and fragmentation of their massifs. Competition by the forest huthatch and the dormice for hollows of trees [18].
Conservation measures taken. Protected according to the Biological Diversity Act. Included in the Red Data Book of Bulgaria (1985). Declared are the Central Balkans National Park, the Rila National Park and the Rila Monastery Natural Park and a network of strict reserves in them (about 70% of the population).
Conservation measures needed. Declaration of protected territories and zones in the Western Rhodopes and Pirin. Ban on felling in old natural coniferous and beech forests in the protected territories and zones. Use of houses for breeding.
References. 1. Voous, 1960; 2. Klain, 1909; 3. Boev, 1962; 4. Spiridonov et al., 1987; 5. Todorov, 1983; 6. Spiridonov, Mileva, 1988; 7. Nikolov et al., 2001; 8. Mitkov, 1998; 9. Spiridonov, 1999a; 10. Kouzmanov et al., 1995; 11. Todorov, Stoyanov, 1996; 12. Spiridonov, 1999b; 13. Shurulinkov, Stoyanov, 2006, in press; 14. Shurulinkov, Stoyanov, 2005; 15. BSPB, in press; 16. Geroudet, 1979; 17. Scherzinger, 1970; 18. Mikkola, 1983; 19. Uttendorfer, 1952.
Authors: Geko Spiridonov, Boris Nikolov, Petar Shurulinkov
