Aristotle's account of the περκνóπτεος the Black Eagle (H.A. ix. 32. b), is, in the main, an accurate enough description of the Lammergeyer (Gypaetus barbatus): λευκἠ κεϕαλἠ, μεγέθει ἠ μἑγιοτος, πτερἀ ἠ βραχύτατα, καì ὀρροπύγιον πρóμκες, γυπí ὃμοιος ὀρειπέλαργος καλε¯ται καí ὑπάετος. οἰkgr;ε’ ἂλση, τἀ μἐν κακἁ ταὐτἀ ἒχων τοῐς ἂλλοις, τν ’ ἀγαθν οὐἑν. ἁλíσκεται γἀρ καì ιὠκεται ὑττò κορἁκων καì τν ἂλλων, βαρύς γα καí κακóβιος καì τἀ τεθνετα ϕἑρων πειν’ ἑεì καì βοᾀ και μινυρíℑει. The birds which I observed in Abyssinia and Kenya appeared very black, and the white head (λευκἠ κεϕαλἡ) was very noticeable when the bird turned in the sun.

Again it is in fact the largest of the Old World raptores (μεγἑθει μἑγιατος), for specimens have been recorded which measured 10 feet between wing-tips. But it is untrue to say that its wings are βραχύτατα, for it possesses the graceful spread of a gigantic falcon. Sundevall, as Professor D'A. W. Thompson points out in A Glossary of Greek Birds (pp. 146–7, new edition, 1936), suggested that βραχύτατα was an error for μακρóτατα, but it is more likely, in view of Pliny's alts minimis, quoted below, that Aristotle was confusing the lammergeyer with another bird, perhaps Bonelli's (Nisaetus fasciatus Vieill.) or the Dwarf Eagle (Aquila naevia). In flight the lammergeyer's most prominent feature is its long, streamlined rump, which is faithfully described by ὀρροπὑγιον πρóμηκες (this characteristic is well portrayed in Leonard Gill's A First Guide to the Birds of South Africa).