Plumage above and below white; quills alone black: occipital feathers long, and filiform: tail cuneated.
N. Percnopterus, Jard. and Selb. Orn. pl. 33. Cathartes Perc-nopterus, Temm. Man. d'Orn. torn. i. p. 8. Egyptian Neophron, Selb. liliest. vol. i. p. 4. pi. A.
Entire length two feet seven inches: length of the bill (from the forehead) two inches six lines; of the tarsus three inches; of the middle toe, claw included, three inches: breadth, wings extended, five feet nine inches. Selby.
(Immature plumage). " Bill brownish black, or horn-coloured: cere somewhat bulging at the base, and occupying half the length of the bill, wine yellow: nostrils in the middle of the cere, large and open: crown of the head, cheeks, and throat, covered with a naked skin, of a livid flesh-coloured red, with a few straggling bristly feathers between the bill and the eyes, and upon the margins of the mandibles: ears round, open, and large: occiput and nape covered with a close, thick-set white down, with small black feathers intermixed: neck clothed with long, arched, and acuminated feathers, forming a kind of ruff of a deep umber brown, tipped with cream yellow: back and scapulars cream white, the latter intermixed and varied with umber brown: lesser wing-coverts nearest the body deep umber brown, margined with a paler shade; these are succeeded by two rows of cream-coloured sharp-pointed feathers: greater coverts umber brown, varied with cream white: secondaries pale umber brown, their tips and margins yellowish white: quills black: tail cuneiform, umber brown at the base, the tip yellowish white: under parts mixed with umber brown: legs strong and fleshy, of a pale yellowish gray: tarsi covered with a rough reticulated skin: middle toe with four entire scales upon the last phalanx; the exterior and interior each with three; hinder toe short and strong: claws blackish brown, strong, but not greatly arched." Selby. In the adult state, the entire plumage is white; the greater quills alone excepted, which are black.
Common in Egypt, and in some parts of the Continent, but not known as a visitant in this country till 1825, in the Autumn of which year, two specimens were observed on the shores of the Bristol Channel near Kilve in Somersetshire, and one killed. From this individual, which proved to be in immature plumage, the above description was taken by Mr Selby. This species is said to feed principally upon carrion, but occasionally on lizards and other reptiles; more rarely attacks living birds and the smaller quadrupeds. Builds in the crevices and hollows of rocks.
(1. Aquila, Cuv).