Avian Flu Detected on Remote Island, Affecting Six Bird Species
Deadly Avian Flu Hits Marion Island, Threatens Seabirds and Wildlife
The highly pathogenic avian influenza (HPAI) H5N1 virus has been confirmed on sub-Antarctic Marion Island, sparking concerns over its impact on local seabird populations.
South Africa’s Department of Forestry, Fisheries, and the Environment announced that samples collected between September and December 2024 were tested upon arrival on the mainland, confirming infections in six bird species. Affected species include the wandering albatross, king penguin, brown skua, southern and northern giant petrels, and the sooty albatross.
Wandering albatross chicks have suffered significant losses, with at least 150 out of 1,900 chicks from the 2024 cohort reported dead. However, adult birds in other species have been hit hardest. Authorities report the deaths of at least 80 brown skuas, 120 king penguins, and smaller numbers of petrels and albatrosses.
The department emphasized that adult seabird deaths pose a greater threat to population stability than chick mortality, as many species only begin breeding after several years and typically raise just one chick per year. The outbreak adds to existing environmental pressures on seabirds, including climate change, plastic pollution, and predation by invasive house mice on Marion Island.
HPAI was first suspected in mid-September 2024 when a brown skua displayed symptoms such as twitching and tremors. The outbreak escalated in early November, with mortality continuing into March. Though the death rate slowed significantly in January, experts caution that seasonal shifts in bird populations make it difficult to predict the virus’s long-term impact.
The department is also monitoring potential effects on marine mammals, though no increased mortality has been observed so far.
Marion Island and its neighboring Prince Edward Island serve as crucial breeding grounds for millions of seabirds and marine mammals, including nearly half of the world’s wandering albatross population and large colonies of penguins, elephant seals, and fur seals. Given the ecological link between the two islands, findings from Marion could indicate future risks for wildlife on Prince Edward Island.
Since 2021, HPAI H5N1 has spread across the globe, reaching seabirds and marine mammals in South Georgia in October 2023 and the Antarctic Peninsula by early 2024. The virus was later detected at the Crozet and Kerguelen archipelagos—located east of Marion Island—by late 2024, likely carried by migrating birds.
On-site field personnel have been trained to monitor and mitigate the virus’s spread on Marion Island. However, officials warn that available disease control measures in such remote environments are limited.
Avian Flu Detected on Remote Island, Affecting Six Bird Species