1. the birds of a particular region, period, or environment
Usage: technical/scientific term; usually used in plural or as a collective noun

Examples

• The avifauna of the Amazon rainforest includes over 1,300 species.
• Ornithologists study the avifauna of wetlands to understand ecosystem health.
• Climate change is affecting the avifauna of northern regions.
• The island's unique avifauna evolved in isolation for millions of years.
• Birdwatchers documented the avifauna during their expedition to the national park.