Population estimates for the diverse raptor assemblage of Dadia National Park, Greece.
Dadia National Park, which is situated in north-eastern Greece, close to the border with Bulgaria and Turkey, is characterised by one of the most diverse arrays of breeding raptorial species in Europe. The first raptor survey was undertaken in the 1970s, but until 1999 most surveys were circumstantial and nonsystematic. Considering some of these species are globally endangered and included in Annex 1 of the Birds Directive, and that raptors in general are considered key indicators of biodiversity and ecosystem health, a systematic raptor monitoring programme was established by WWF Greece in 2000. This paper presents the results of this programme including the population status, trends and breeding densities of raptors from 2001 to 2005. Some 18–19 species bred in the area regularly, at densities ranging from one pair per 100 km2 (e.g. long-legged buzzard Buteo rufïnus and peregrine falcon Falco peregrinus) to 30 pairs per 100 km2 (common buzzard Buteo buteo). The total number of raptor territories was stable with an average of 321 ± 15.5 territories (77 territories/100 km2) with no overall trend and little fluctuation. Although the population size has increased for several species since the mid 1990s, data from the first surveys in the 1970s suggest that some species are still recovering from the decline suffered in the 1980s. The populations of six species have remained stable since the 1970s, whilst five species, including the Egyptian vulture Neophron percnopterus, have shown a gradual decline. The black vulture Aegypius monachus was the only species with a confirmed increase, a further three species showing a probable increase. The long-term trend for four species, including the common buzzard, is unknown due to insufficient data from the 1970s.