Marsh Harrier
Circus aeruginosus (Linnaeus, 1758)
Order Falconiformes
Family Accipitridae
Conservation status: in Bulgaria: Endangered EN=D, BDA-II, III (I); International: CITES-II, BeC-II, BoC-II, ESC-Spec 2, BD-I.
General distribution. A Palearctic species whose breeding area embraces Northwestern Africa, Europe and Asia, Australia, New Zealand and some islands of the Pacific and the Indian Ocean. It winters to the south of tropical Africa and in Southern Asia.
Distribution and abundance in Bulgaria. A breeding summer visitor, passage migrant and winter visitor. In the past it was common, but in the second half of the 20th century it became more and more rare [1]. In the 1950-1984 period, a total of 38 breeding habitats were registered, with 40-60 pairs (mainly on islands on the Danube, in marshes, lakes and mouths of rivers along the Black Sea coast and wetlands in the Sofia field and the Upper Thracian lowland), of which 16 certain, with 27 breeding pairs [2]. At present, during the multiplication season it has been registered in about 150 ten-kilometer UTM squares (of which 54 with certain breeding), situated in the low parts of the territory of the country [3]. The estimates of the breeding population are 30-50 [4], 400-600 [5], 80-150 [6] and 220-240 pairs [3], which showed some increase in the last years.
Habitats. Marshes, lakes and mouths of rivers with thick vegetation of reed and rush; during migrations and wintering – different natural and artificial wetlands in the low parts of the country.
Biology. Singularly breeding pairs predominate, but small breeding colonies are known as well. The nest is hardly accessible, located low among the thick marsh vegetation. It breeds 4-5 young ones that fly away in July.
Similar species. Circus macrourus, Circus pygargus, Circus cyaneus.
Negative factors. Drying up and degradation of the natural wetlands with standing waters; the use of poisons for combating rodents; disturbance by fishermen.
Conservation measures taken. Protected according to the Biological Diversity Act. Included in the Red Data Book of Bulgaria (1985).
Conservation measures needed. Working out a programme for its preservation; updating the National Plan for the Preservation of the wetlands in the country.
References. 1. Simeonov et al., 1990; 2. Petrov, Michev, 1985; 3. BSPB, in press; 4. Kostadinova, 1997; 5. Nankinov et al., 2004; 6. Birflife International, 2004.
Authors: Tanyo Michev, Tseno Petrov, Svetoslav Spasov
