Source : Webster's Revised Unabridged Dictionary (1913)

Ornithomancy \Or*nith"o*man`cy\, n. [Gr. ?; ?, ?, a bird + ?
   divination: cf. F. ornithomancie.]
   Divination by means of birds, their flight, etc.

         Ornithomancy grew into an elaborate science. --De
                                                  Quincey.