1. The birds of a particular region, period, or environment considered as a group
The avifauna of the Amazon rainforest is incredibly diverse and colorful.
A avifauna da floresta amazônica é incrivelmente diversa e colorida.
2. The study or science of birds characteristic to a specific area or habitat
Ornithologists conducted a survey of the local avifauna.
Os ornitologistas realizaram um levantamento da avifauna local.