Density, nest spacing, breeding success and diet of a kestrel Falco tinnunculus urban population

The Kestrel breeding population in Rome urban area was studied from 1995 to 1998. Breeding density was very high (9.5 pairs/km2) in the city-centre, showing weak variations among years, and relatively high in some suburbs (0.3-0.6 pairs/km2). Nest spacing was very low in the city-centre, where many scattered close nesting situations were recorded. Occupied nest sites were scaffolding holes in roman ruins and old churches, eaves in nineteenth century buildings, natural cavities in cliffs and stick nests on trees. The breeding success was similar to those recorded in other European urban areas. Summer diets were primarily composed by insects, reptiles, birds and small mammals. Feral pigeons, swifts and bats were taken only in the city-centre. Prey abundance, especially birds and bats, and availability of suitable nest-sites, especially scaffolding holes in ruins, may explain the high breeding density and the low nest-spacing in the city-centre.