The golden eagle (Aquila chrysaetos) is one of the best-known birds of prey in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. These birds are dark brown, with lighter golden-brown plumage on their napes. Immature eagles of this species typically have white on the tail and often have white markings on the wings. Golden eagles use their agility and speed combined with powerful feet and massive, sharp talons to snatch up a variety of prey (mainly hares, rabbits, marmots and other ground squirrels). Golden eagles maintain home ranges or territories that may be as large as 200 km2 (77 sq mi). They build large nests in high places (mainly cliffs) to which they may return for several breeding years. Most breeding activities take place in the spring; they are monogamous and may remain together for several years or possibly for life. Females lay up to four eggs, and then incubate them for six weeks. Typically, one or two young survive to fledge in about three months. These juvenile golden eagles usually attain full independence in the fall, after which they wander widely until establishing a territory for themselves in four to five years. Once widespread across the Holarctic, it has disappeared from many areas which are now more heavily populated by humans. Despite being extirpated from or uncommon in some of its former range, the species is still fairly ubiquitous, being present in sizeable stretches of Eurasia, North America, and parts of North Africa. It is the largest and least populous of the five species of true accipitrid to occur as a breeding species in both the Palearctic and the Nearctic. For centuries, this species has been one of the most highly regarded birds used in falconry, with the Eurasian subspecies having been used to hunt and kill prey such as gray wolves (Canis lupus) in some native communities. Due to its hunting prowess, the golden eagle is regarded with great mystic reverence in some ancient, tribal cultures.The golden eagle is one of the most extensively studied species of raptor in the world in some parts of its range, such as the Western United States and the Western Palearctic.