Ornithology

[,ɔːnɪ'θɒlədʒɪ] or [,ɔrnɪ'θɑlədʒi]

(noun.) the branch of zoology that studies birds.

Edited by Francine--From WordNet

(n.) That branch of zoology which treats of the natural history of birds and their classification.

(n.) A treatise or book on this science.

Edited by Aaron