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): λευκ κεαλ, μεγέθει μγιοτος, πτερ βραχύτατα, καì ρροπύγιον πρóμκες, γυπí μοιος ρειπλαργος καλε¯ται καí πετος. οkgr;ε’ λση, τ μν κακ τατ χων τοῐς λλοις, τν ’ γαθν ον. λíσκεται γρ καì ικεται ττò κορκων καì τν λλων, βαρύς γα καí κακóβιος καì τ τεθνετα ρων πειν’ εì καì βοᾀ και μινυρíει. The birds which I observed in Abyssinia and Kenya appeared very black, and the white head (λευκ κεαλ) was very noticeable when the bird turned in the sun.
Again it is in fact the largest of the Old World raptores (μεγθει μγιατος), 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 ρροπγιον πρóμηκες (this characteristic is well portrayed in Leonard Gill's A First Guide to the Birds of South Africa).