Selection of nest cliffs by Bonelli's Eagle (Hieraaetus fasciatus) in southeastern Spain

A total of 119 nests and 52 cliffs occupied by 32 Bonelli's Eagle (Hieraaet us fasciatus) pairs was studied during 1995-97 in southeastern Spain. Mean number of nests built by pairs exceeded that reported in previous studies ( (x) over bar = 3.7; N = 32) and there was a trend among eagles to build the ir nests with a southeastern orientation. Breeding density was directly rel ated to the availability of cliffs. Eagles occupied higher cliffs ((x) over bar = 52.9 m; N = 32), located on steeper slopes ((x) over bar = 34.7 degr ees; N = 31) than was available. Occupied cliffs were highly heterogeneous due to die fact that use of different areas by Bonelli's Eagles was depende nt on human disturbance. Thus, occupied cliffs with the shortest linear dis tance to paved roads were higher than occupied cliffs far from paved roads. Selection of high cliffs located on steep slopes with southern orientation s may have been associated with the additional lift provided eagles, since these types of nest sites enhanced the possibility of thermal and slope soa ring. Preservation of nest cliffs free from disturbances should be undertak en to ensure the survival of Bonelli's Eagle in this area of Spain.