Bone composition and bone mineral density (BMD) of long bones of two raptor and one owl species were assessed. Right humerus and tibiotarsus of 40 common buzzards, 13 white-tailed sea eagles and 9 barn owls were analyzed. Statistical analysis was performed for influence of species, age, gender and nutritional status. The BMD ranged from 1.8 g/cm3 (common buzzards) to 2.0 g/cm3 (white-tailed sea eagles). Dry matter was 87.0% (buzzards) to 89.5% (sea eagles). Percentage of bone ash was lower in sea eagles than in buzzards and owls. Content of crude fat was lower than 2% of the dry matter in all bones. In humeri lower calcium values (220 g/kg fat free dry matter) were detected in sea eagles than in barn owls (246 g/kg), in tibiotarsi no species differences were observed. Phosphorus levels were lowest in sea eagles (humeri 104 g/kg fat free dry matter, tibiotarsi 102 g/kg) and highest in barn owls. Calcium- phosphorus ratio was about 2:1 in all species. Magnesium content was lower in sea eagles (humeri 2590 mg/kg fat free dry matter, tibiotarsi 2510 mg/kg) than in buzzards and owls. Bones of barn owls contained more copper (humeri 8.7 mg/kg fat free dry matter, tibiotarsi 12.7 mg/kg) than in the Accipitridae. Zinc content was highest in sea eagles (humeri 278 mg/kg fat free dry matter, tibiotarsi 273 mg/kg) and lowest in barn owls (humeri 185 mg/kg, tibiotarsi 199 mg/kg). The present study shows that bone characteristics can be considered as species specific in raptors.
