AviList: First-Ever Unified Global Bird Checklist Goes Live

In a landmark moment for ornithology and biodiversity conservation, AviList, the first-ever unified global checklist of bird species, officially went live on June 12, 2025, marking the culmination of four years of extensive collaboration and research by the Working Group on Avian Checklists. This groundbreaking initiative has successfully brought together global consensus on bird classification, offering a single reference point for bird species across the world.

The checklist, which has now replaced the previously used International Ornithological Committee (IOC) and Clements lists, will be updated annually, according to a statement by BirdLife International—a global partnership of non-governmental organisations focused on the conservation of birds and their habitats. This move aims to eliminate the inconsistencies and confusion caused by the use of multiple species lists, each with different criteria for defining bird species.

Developed through a broad and inclusive partnership, the Working Group on Avian Checklists included experts from BirdLife International, the Cornell Lab of Ornithology, the American Ornithologists' Society, the International Ornithologists’ Union, and Avibase—a comprehensive bird database system. Together, these institutions have compiled a unified taxonomy that will standardise avian classification globally.

The newly released AviList contains a wealth of detailed information, listing:

• 11,131 bird species

• 19,879 subspecies

• 2,376 genera (a taxonomic category ranking above species and below family)

• 252 families (groups of genera with shared characteristics)

• 46 orders (higher-level groupings that include several families with broad similarities)

This comprehensive structure reflects an evolved understanding of bird classification and provides a more accurate view of the avian world. Importantly, the unified list reshapes how scientists and conservationists approach species identification, ecological research, and biodiversity policy.

According to Stuart Butchart, Chief Scientist at BirdLife International, the adoption of a single global taxonomic list brings wide-reaching benefits. “It removes the confusion and uncertainty created by multiple lists, making it easier for birders, scientists, policymakers, and conservationists to align their work and communicate more effectively. It also enhances our ability to understand and prioritise avian conservation needs,” he said in the official release.

Until now, the avian science community has worked with multiple checklists, each built on different taxonomic interpretations of what defines a species—a concept that itself varies depending on evolutionary, genetic, and behavioral factors. This lack of standardisation has often complicated data sharing and conservation planning across platforms and countries.

“A unified checklist ensures that everyone is speaking the same scientific language,” said Marshall Iliff, a member of the AviList team and eBird project leader at the Cornell Lab of Ornithology. He emphasized that having standardised data is critical for global-scale conservation efforts, particularly when trying to protect migratory species or monitor threatened populations across borders.

The AviList is available freely to the public at https://www.avilist.org, where it can be downloaded in full or as a shortened version containing only the essential fields. Both .xlsx and .csv file formats are offered, enabling wide accessibility for researchers, conservationists, educators, and bird enthusiasts.

By harmonising global avian taxonomy, AviList stands to become an essential tool for advancing bird research, fostering international cooperation, and informing policies that protect bird species and the ecosystems they depend on.