How is bird flu affecting animal populations?

The world is currently seeing the fastest-spreading, largest-ever outbreak of H5N1, a highly contagious, deadly strain of avian influenza. Scientists say this virus now presents an existential threat to the world’s biodiversity, with the risk to humans rising as it continues to leap the species barrier, reaching new host species. 

• H5N1 has already impacted at least 485 bird species and 48 mammal species, killing seals, sea otters, dolphins, foxes, California condors, albatrosses, bald eagles, cougars, polar bears and a zoo tiger. Since it broke out in Europe in 2020, this virus has spread globally. Carried by birds along migratory pathways, it has invaded six continents, including Antarctica.
• This current H5N1 animal pandemic (or panzootic) was caused by humans: A mild form of avian flu carried by wild birds turned deadly when it infected domestic poultry. Many industrial-scale poultry farms adjoin wetlands where migrating birds congregate, facilitating rapid spread.
• The toll on some bird and mammal populations has been devastating. With continued outbreaks, some imperiled species could be pushed to the brink, with wildlife already fighting to survive against a changing climate, disappearing habitat and other stressors.

Brown skuas and south polar skuas, two gull-like species that nest in Antarctica, are sometimes called the “pirates of the Southern seas.” These migratory seabirds are fierce, competitive predators that hunt or scavenge anything, from eggs and adult birds to seafood, mammals or garbage.