The Collaborative International Dictionary of English v.0.48:

Gier-eagle \Gier"-ea`gle\, n. [Cf. D. gier vulture, G. gier, and
   E. gyrfalcon.] (Zool.)
   A bird referred to in the Bible (--Lev. xi. 18and --Deut.
   xiv. 17) as unclean, probably the Egyptian vulture (Neophron
   percnopterus).
   [1913 Webster]