The Impact of Avian Flu on Wild Animals: A Growing Crisis

As the world grapples with the ongoing spread of the H5N1 avian flu virus, scientists have voiced concerns not only about its potential to cause another human pandemic, but also about its devastating effects on wildlife.

Although much attention has focused on human health, the virus is already causing substantial harm to species in the wild, particularly birds. The toll it is taking on avian populations underscores the urgency of addressing the challenges facing wildlife in a world already strained by climate change, habitat loss, and human activity.

In May 2022, a massive die-off of northern gannets, seabirds that breed along the coast of eastern Canada, began. As many females prepared to lay eggs, the birds succumbed to the newly arrived H5N1 virus. Thousands of gannets washed up on the shore, and by the end of the year, tens of thousands had perished. According to Stephanie Avery-Gomm, a seabird biologist with Environment and Climate Change Canada, the loss was “devastating” and unprecedented in its scale. This outbreak was just one example of the growing impact of H5N1 on wildlife populations around the world.

Since the virus re-emerged in 2020, it has evolved to affect wild birds more easily. Once primarily a concern for farmed poultry, the H5N1 strain now circulates globally, carried by migratory birds, with reported cases spanning from the Americas to Antarctica. By 2021, more than 117,000 wild birds from over 300 species had died from the virus, a number that is likely much higher due to the underreporting of deaths in remote regions.

The virus has caused particularly severe outbreaks in seabirds, whose large colonies facilitate rapid transmission. The northern gannet, for example, saw mortality rates as high as 75% in some breeding colonies. Similarly, the virus devastated populations of pelicans in Peru and penguins in Chile. Raptors, such as bald eagles, have also been affected, with sharp declines in reproductive success observed in the United States. The virus is even impacting endangered species, including the California condor, which has prompted a vaccination campaign to protect the remaining population.

While there is no evidence that these outbreaks are driving species to extinction, the cumulative stress from avian flu adds further strain to bird populations that are already facing numerous threats.

“This disease isn’t being popped into a lovely, pristine, resilient ecosystem,” explained Ruth Cromie, coordinator of a United Nations task force on avian influenza. “This is a disease that is adding pressures to species that are already really up against it.”

The consequences of these deaths are profound, as the loss of large numbers of individuals can push populations closer to the brink of collapse. For slow-reproducing species like seabirds, recovery may take decades. Moreover, as populations are weakened by disease, they may become more vulnerable to other threats such as heatwaves, pollution, and habitat destruction.

Although the virus has not yet caused widespread extinctions, its effects are being felt across ecosystems. Marine mammals, including sea lions in South America, have also experienced significant losses due to the spread of H5N1. In Argentina, an outbreak during the breeding season decimated seal populations, potentially leading to long-term disruptions in their reproductive success.

Looking forward, experts warn that H5N1 is unlikely to disappear any time soon. As the virus continues to evolve, the possibility of future outbreaks in regions like Antarctica, Australia, and New Zealand remains a serious concern. Scientists stress the need for comprehensive conservation efforts that address not just avian influenza but the broader environmental challenges facing wildlife. By improving habitat protection, reducing pollution, and tackling overfishing, we can help strengthen the resilience of bird populations and other wildlife against the mounting threats they face.