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Ecology
Breeding habitats
In Portugal, Bonelli's eagles breed in several habitat types. In the North they use exclusively rocky substrates, mostly in cliffs hanging over steep river canyons, but sometimes also on rocky crests topping mountainous areas. These situations are similar to what is commonly found along the Mediterranean basin. This type of habitat is also chosen throughout the international section of the Tagus river, however in this region tree nesting also occurs (2 pairs nesting on trees; 2 pairs both on rocks and trees). In the Estremadura (Central-West coastal belt), some pairs still occur in rocky habitats while most use dense woods for breeding. In the South, however, most nests are set on trees, and this type of substrate is the only one used in the uplands of the Southwest and in the Southeast plains. Nests are built on tall trees, which dominate relatively dense forest stands, otherwise in smaller forest patches or even on isolated trees. Trees used may be Cork oaks Quercus suber, Maritime pines Pinus pinaster, Monterey pines Pinus radiata or Eucalyptus Eucalyptus globulus and E. rostrata. Nests built on eucalyptus are at the greatest heights, mostly between 25 and 28 m above ground.
Diet
Bonelli's eagles feed on a wide variety of middle and small-sized prey, mostly birds. Nevertheless, their diet is considerably based in a few abundant middle-sized staple items. In the low mountains of the Southwest, 82.3% of the diet is made of only 4 species: first of all, domestic pigeons Columba livia var. domestica (39.2%), followed by European rabbits Oryctolagus cuniculus (18,4%), Red-legged partridges Alectoris rufa (17.2%) and Jays Garrulus glandarius (7,5%). The remaining 17.7% are shared by species as small as Goldfinches Carduelis carduelis and as large as Grey Herons Ardea cinerea. The importance of domestic pigeons raised in rural lofts in the eagle's diet is noteworthy, and compensates for the relative scarcity of traditional wild prey, namely rabbits and partridges. In territories where most usual prey is scarce e.g. where a high percentage of the area is occupied by poor habitats such as eucalyptus plantations, the prey range is consequently widened as a response.
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