Word Study
avifauna
CIDE DICTIONARY
avifauna, n. [NL., fr. L. avis bird + E. fauna.].
The birds, or all the kinds of birds, inhabiting a region. [1913 Webster]
OXFORD DICTIONARY
avifauna, n. birds of a region or country collectively.
Etymology
L avis bird + FAUNA
For further exploring for "avifauna" in Webster Dictionary Online