Divination by means of the flight and cries of birds; augury.
Origin
Mid 17th century; earliest use found in John Gaule (1603/4–1687), Church of England clergyman and author. From Byzantine Greek ὀρνιθομαντεία divination from birds, augury from ancient Greek ὀρνιθο- + μαντεία. Compare French ornithomancie.