EN
This study was carried out on 150 km² of farmland with a 7% woodland cover and fairly numerous isolated clumps of trees (2%). During the period 1971-1985 the species composition and density of the breeding and wintering populations of predatory birds was investigated. The results of breeding in Buteo buteo and Accipiter gentilis are analysed. Seven species were found to breed (density in brackets): Buteo buteo - 13-37 pairs (initially 10 pairs/100 km²; towards the end of the study period 20 pairs/100 km²); Accipiter gentilis - returned after an absence of 8 years: 3 breeding pairs in 4 years (2 pairs/100 km²); Circus aeruginosus - 2-6 pairs (2.6 pairs/100km²); Circus cyaneus-1-3pairs-nested until 1978; Falco tinnunculus-1-8 pairs - nested until 1982. In addition, Falco subbuteo and Milvus milvus nested occasionally (Table 1). On average. Buzzards laid clutches of 2.8 eggs, had a breeding success of 72% and raised 1.7 young per breeding pair. The average clutch of Accipiter gentilis was 3.0 eggs from which an average of 2.0 young per breeding pair were raised (Table 2). The wintering population of Buteo buteo consisted mainly of immigrant birds. The combined density of Buteo buteo and B. lagopus was c. 100 birds/100 km² (Table 3). Circus cyaneus and Falco tinnunculus overwintered on occasion. The numbers of Accipiter gentilis and A. nisus are only approximate.