avifauna

Avifauna is the assemblage of bird species present in a particular region, habitat, or time period. The term is used in ecology and biogeography to distinguish birds from other animal groups, and to focus on species composition, abundance, and distribution. Avifauna includes resident species, seasonal migrants, and historically documented species, including those that are now extinct or extirpated in a region.

Global avifauna comprises roughly 10,000 to 11,000 described species in the class Aves. Richness is greatest in tropical regions, with substantial diversity on continents and in island ecosystems. Many avifaunal communities show endemism, where species occur only in restricted areas.

Birds fulfill diverse ecological roles: seed dispersal and pollination by fruit- and nectar-eating species; insect population regulation; scavenging; and prey for higher predators. They can serve as indicators of environmental change and habitat quality; shifts in avifaunal composition often reflect alterations in land use, climate, or pollution.

Study and monitoring of avifauna rely on field surveys such as fixed-point counts, transect surveys, mist-netting, and citizen science data. International and national inventories collate records for conservation assessment, with the IUCN Red List providing statuses for species.

Human activities threaten avifauna through habitat loss, overexploitation, invasive species, climate change, and light and noise pollution. Conservation strategies include habitat protection, restoration, legal protections, and monitoring programs. Avifauna is also a focus of ecotourism and cultural appreciation in many regions.