Source : Webster's Revised Unabridged Dictionary (1913)

Ornithologist \Or`ni*thol"o*gist\, n. [Cf. F. ornithologiste.]
   One skilled in ornithology; a student of ornithology; one who
   describes birds.

Source : WordNet®

ornithologist
     n : a zoologist who studies birds [syn: {bird watcher}]