What type of bird flu killed more than 50 skuas in Antarctica in February 2026, marking the first wildlife die-off on the continent?

The highly pathogenic avian influenza virus, H5N1, was identified as the cause of death for over 50 skuas in Antarctica during the austral summers of 2023 and 2024. This tragic event, confirmed by studies published in February 2026, marks the first documented wildlife die-off from the bird flu virus on the Antarctic continent. The affected skuas, which are predatory seabirds related to gulls, exhibited severe neurological symptoms, including twisted necks and circling behavior, before succumbing to the illness.

The H5N1 strain responsible for this outbreak, specifically clade 2.3.4.4b, has been on an unprecedented global spread since 2020, impacting wild bird populations and various mammal species across multiple continents. Originating from poultry, the virus mutated and spilled back into wild birds, which then carried it along migratory pathways. Before reaching Antarctica, H5N1 devastated wildlife in South America, causing mass mortalities in sea lions and elephant seals in countries like Argentina and Chile. The arrival of the virus in Antarctica, previously the last unaffected continent, underscores its remarkable ability for long-distance transmission and adaptation.

This die-off is particularly concerning due to Antarctica's pristine and often immunologically naive wildlife populations, which may have little natural resistance to such a virulent pathogen. Skuas, as scavengers, play a crucial ecological role but their feeding habits could also facilitate further transmission of the virus within the Antarctic ecosystem. The confirmed presence and lethal impact of H5N1 pose a significant threat to the continent's unique biodiversity, including other vulnerable species like penguins, which breed in dense colonies and could be highly susceptible to rapid viral spread.