The Collaborative International Dictionary of English v.0.48:
Avifauna \A`vi*fau"na\, n. [NL., fr. L. avis bird + E. fauna.] (Zool.) The birds, or all the kinds of birds, inhabiting a region. [1913 Webster]WordNet (r) 3.0 (2006):
avifauna n 1: the birds of a particular region or period