Bird Flu Invades Wildlife Populations

At dawn, on a beach along California’s central coast, the sand is usually alive with wiggling of northern elephant seals, but in recent days, researchers from Beltran Lab at UC Santa Cruz and UC Davis have noticed that several seal pups are sick at Ano Nuevo State Park.

These observations led scientists to conduct several tests, and they confirmed that the young northern elephant seals have been infected by H5N1—widely known as bird flu—making it the first time that virus has been detected in elephant seals in California.

More veterinarians began to investigate and discovered a large-scale outbreak could pose a significant threat to the seals, which were hunted almost to extinction for their blubber in the 19th century, as well as to people. “Our primary concern right now is to limit spread in this colony,” Dr. Christine Johnson, a veterinary epidemiologist at the University of California, said at a news briefing on Wednesday.

Scientists believe that infected wild birds likely spread the virus. Over the last few years, a new version of H5N1 has even infected an unusually broad array of birds, including bald eagles, peregrine falcons and Gentoo penguins. It has also spread to both wild and domesticated mammals, including foxes, bears, cats and cows. Furthermore, since 2024, the Centers for Disease Control and Prevention, the leading national public health institute in the United States, have received of human infection; one older adult even died in the beginning of 2025 because of bird flu.

Fortunately, researchers said that most of the seals appear to be healthy, but officials have urged travelers and visitors to keep distance from them and avoid approaching any wildlife that seem to be sick.

As scientists continue to test animals along the coast, the colony at Ano Nuevo State Park has become a warning of how viruses could spread so fast between wildlife, and how they could eventually affect human health.