Circus pygargus Linnaeus, 1758
Conservation status: in Bulgaria: Vulnerable VU=C[a(i)+b], BDA-III; International: IUCN-LC, CITES-II, BeC-II, BoC-II, BD-I.
General distribution. A European-Turkestan species with numbers between 10 000 – 1 000 000 individuals. The European population is less than 65 000 pairs, with 50% of the breeding area.
Distribution and abundance in Bulgaria. A breeding summer visitor, passage migrant and winter visitor. Until 1985, it was found throughout the country during migration, more often along the Black Sea coast ; during the winter, singular individuals were reported . At present, breeding is proved for many regions of Western Bulgaria (including the Sofia field), the valley of the river Maritsa and Southeastern Bulgaria . Territories with the highest breeding density are the Derventski Vazvisheniya (hills), the regions of the Malko Sharkovo reservoir, Yambol region, and Stara Zagora field. Its numbers for 1990 are estimated at not more than 30-50 pairs  30-60 pairs for 1997 , and in 2004 up to 180-220 pairs . According to other estimates, the total numbers are 220-270 breeding pairs .
Habitats. Various wetlands (including wet meadows, marshes, turf areas) to which it shows a marked preference. In Bulgaria it often breeds in arable areas, most frequently sown with wheat. Outside the multiplication period, the connection with the wetlands weakens considerably .
Biology. It breeds singularly or in thinned colonies. It migrates singularly or in pairs, especially in the autumn, sometimes forming small flocks with other hawks when crossing large water areas . It feeds on eggs and the young of birds breeding on the ground, rodents, small hares, lizards, large insects .
Similar species. The Pallid Harrier (Circus macrourus).
Negative factors. The major threat for the nests in arable lands is the destruction of the clutch during harvesting. To a lower degree it is threatened by the loss of habitats, disturbance, clashing with high-voltage lines and wind turbines, illegal shooting by poachers, poisoning.
Conservation measures taken. Protected according to the Biological Diversity Act. Included in the Red Data Book of Bulgaria (1985). Current campaigns against illegal shooting by poachers and the use of pesticides, inclusion of the habitats of some of the species in the National Ecological Network. Giving aid to wounded birds in the Centre for Rehabilitation and Multiplication of Rare Species in the city of Stara Zagora.
Conservation measures needed. Annual mapping of the breeding colonies, especially those larger than 10 pairs, localizing the nests and their protection by enclosing them (with bales of hay) in a radius of 15 m. Postponing the harvesting in cases of localizing larger colonies, compensations paid to land owners for losses as a result of conservation measures taken.
References. 1. Profirov, 1981; 2. Prostov, 1964; 3. Iankov, in press; 4. Simeonov et al., 1990; 5. Kostadinova, 1994; 6. Nankinov et al., 2004; 7. Cramp, Simmons, 1989; 8. Shurulinkov et al., 2005.
Authors: Simeon Marin, Bozhidar Ivanov, Ivelin Ivanov, Svetoslav Spasov