The common buzzard (Buteo buteo) is a medium-to-large bird of prey which has a large range. A member of the genus Buteo, it is a member of the family Accipitridae. The species lives in most of Europe and extends its breeding range across much of the Palearctic as far as the northwestern China (Tien Shan), far western Siberia and northwestern Mongolia. Over much of its range, it is a year-round resident. However, buzzards from the colder parts of the Northern Hemisphere as well as those that breed in the eastern part of their range typically migrate south for the northern winter, many culminating their journey as far as South Africa. The common buzzard is an opportunistic predator that can take a wide variety of prey, but it feeds mostly on small mammals, especially rodents such as voles. It typically hunts from a perch. Like most accipitrid birds of prey, it builds a nest, typically in trees in this species, and is a devoted parent to a relatively small brood of young. The common buzzard appears to be the most common diurnal raptor in Europe, as estimates of its total global population run well into the millions. The common buzzard is a medium-sized raptor that is highly variable in plumage. Most buzzards are distinctly round headed with a somewhat slender bill, relatively long wings that either reach or fall slightly short of the tail tip when perched, a fairly short tail, and somewhat short and mainly bare tarsi. They can appear fairly compact in overall appearance but may also appear large relative to other commoner raptorial birds such as kestrels and sparrowhawks. The common buzzard measures between 40 and 58 cm (16 and 23 in) in length with a 109–140 cm (43–55 in) wingspan. Females average about 2–7% larger than males linearly and weigh about 15% more. Body mass can show considerable variation. Buzzards from Great Britain alone can vary from 427 to 1,183 g (0.941 to 2.608 lb) in males, while females there can range from 486 to 1,370 g (1.071 to 3.020 lb).