LONG-TERM STUDY OF A GOSHAWK BREEDING POPULATION ON A MEDITERRANEAN MOUNTAIN (ABRUZZI APENNINES, CENTRAL ITALY) - DENSITY, BREEDING PERFORMANCE AND DIET

The breeding density, breeding performance and breeding diet of a Medi terranean population of Goshawks (Accipiter gentilis) were studied in central Italy over a 10-yr period. Sixteen goshawk nesting pairs were found within a 318 km(2) area (5.03 pairs/100 km(2)). The minimum dist ance between pairs averaged 3.5 km. I observed a total of 51 nesting a ttempts at seven nest sites. Annual mean productivity of breeding pair s was 2.28 fledgings/successful pair and 1.69 fledgings/egg-laying pai r. The occurrence of nesting failures was correlated with rainfall dur ing April-May (r = 0.77, P < 0.01) and brood size at fledging was rela ted to laying date (r = -0.71, P < 0.05). The diet included 20 species of birds (representing 75% of the prey and 71% of the biomass) and si x species of mammals (representing 25% of the prey and 29% of the biom ass). Wood Pigeon (Columba palumbus), Jay (Garrulus glandarius), Mistl e Thrush (Turdus viscivorus), red squirrel (Sciurus vulgaris) and edib le dormouse (Glis glis) accounted for 67% of all prey captures. In ter ms of biomass, Jays (20.76%), Wood Pigeons (16.03%), red squirrels (12 .64%) and edible dormice (12.29%) were the dominant prey. I found 23 p lucking sites on the ground (44.2%), 21 on rock with moss (40.4%), sev en on tree stumps (13.5%) and one on the root of an uprooted tree (1.9 %).