The Himalayan vulture has dark brown greater covert feathers, tail and wing quills, but a pale buff uniform upperside and paler tipped inner secondaries; its legs are covered with buffy feathers and vary in colour from greenish grey to pale brown. The underside and under-wing coverts are pale brown or buff, almost white in some individuals. The whitish down on the head of immatures changes to yellowish in adults who have a long and pale brown ruff with white streaks and long and spiky ruff feathers.[6] The pale blue facial skin is lighter than the dark blue in Gyps fulvus with this species having a yellowish bill. In flight the long fingers are splayed and there is a pale patagial stripe on the underwing. The wing and tail feathers are dark and contrast with the pale coverts and body, one of the best methods to distinguish this species from the slightly smaller griffon vulture.[4][7] The feathers on the body have pale shaft streaks.[6][8][9] It is the largest of the Gyps species, averaging larger in every method of measurement than its relatives, and is perhaps the largest and heaviest bird in the Himalayas.[5] Weight in Himalayan vultures ranges from 6 kg (13 lb)[10] to 12.5 kg (28 lb).[11] It has been estimated to weigh an average of 9 kg (20 lb), but weights vary with conditions from 8–12 kg (18–26 lb).[5][12][13] Published measurements of the wingspan vary from 2.56 to 3.1 m (8 ft 5 in to 10 ft 2 in), a similar range to that of cinereous vulture,[5][6] but the wingspan varies greatly depending on the method used to measure them. It differs from the similar-coloured Indian vulture (G. indicus) by a stouter, more robust bill; younger birds have a pale bill and tend to have buffy-white streaks on the scapulars and wing coverts contrasting with dark brown underparts.[6] It is similar in size to the cinereous vulture (Aegypius monachus), which typically has a slightly shorter overall length but can weigh more than the Himalayan vulture.[5][15]