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Key points:

• Since late 2024, the avian influenza virus H5N1 has been spreading rapidly through wild bird populations, possibly spurred by fall migration.
• Waterfowl and seabirds have been hit hard, though infections in songbirds remain uncommon.
• Experts say feeders don't pose a major risk, but you should clean them regularly and track guidance from local and state wildlife authorities.

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Wild birds are facing a dangerous moment for avian influenza. Since late 2024, wildlife agencies and rehabilitators across the U.S. have reported major die-offs of birds linked with the highly pathogenic avian influenza virus H5N1: Snow Geese in Pennsylvania, Red-breasted Mergansers in Chicago, Eared Grebes around Utah’s Great Salt Lake. Meanwhile, outbreaks have torn through poultry and dairy farms, infected a range of mammals from pet cats to elephant seals, and raised the concerns for a potential crossover to a human pandemic.

“We’re in the throes—or maybe at the end of the throes—of a pretty active period for avian influenza,” one possibly spurred by fall migration, says Richard Webby, a virologist at St. Jude Children’s Research Hospital who focuses on influenza. 

So what does this surge mean for people who feed birds? Feeders don’t currently present a major risk of spread, experts told ���Ϲ���, especially as the virus doesn’t commonly infect the songbirds that visit feeding stations. Still, to protect avian life—along with people and other animals—it’s important to stay up to date with the latest guidance from local, state, and federal wildlife authorities. As officials monitor the virus, they may recommend temporarily removing feeders, avoiding certain habitat areas, reporting sick or dead birds, or taking other precautions. ���Ϲ���, for its part, recommends removing feeders if at least one of your local agencies advises taking them down.

Scientists have been on high alert about avian flu since 2020, when a new, “supercharged” lineage of the virus—known as clade 2.3.4.4b—started to take off, says Webby. After exploding in Europe, this version of the virus showed up in Canada in 2021 and quickly worked its way down through the Americas, eventually reaching all the way to Antarctica. 

Versions of avian influenza have long circulated in bird populations, but in the past, they mainly cropped up in domestic poultry and transferred from farm to farm, says Johanna Harvey, a wildlife disease ecologist at the University of Rhode Island. With this latest version, though, the virus has been infecting a broad variety of wild birds, spreading far and wide along their migratory routes. “Now, wild bird migration is really what is driving the persistence of this disease, and the geographic spread and range,” Harvey says. “And the scale of the mortalities is larger than we've ever seen before.”

The virus has ebbed and flowed in recent years, often seeing an uptick after fall migration. Much of last year saw a slight reprieve in infections, which Harvey attributes to some birds having immunity: “A lot of birds got infected early on,” she says. “If they survived, it means they were able to mount an immune response, and then they have antibodies.” But infections and deaths in wild birds came roaring back at the end of 2024, possibly because migrating populations included birds with waning antibodies and juveniles that had never been exposed to the virus, she adds. 

Recent months have also seen the rise of a new genotype of the virus, D1.1, which quickly became the dominant version spreading along the flyways. Though Webby says it’s hard to draw direct comparisons to earlier years, since birds’ levels of immunity have changed, this genotype seems to be well adapted to infecting wild birds and caused significant die-offs during fall migration.

The USDA’s Animal and Plant Health Inspection Service, which tracks highly pathogenic avian influenza across the country, has more than 12,000 cases detected in wild birds since 2022. And this is probably a small fraction of the true toll, Harvey points out, since disease surveillance of wild bird populations remains limited.

Birds like ducks, geese, and gulls, which are historically the main hosts for avian flu, are still heavily impacted: Some of the latest USDA reports include Blue-winged Teals in Louisiana and Mallards in Indiana. Raptors, seabirds, and corvids are increasingly becoming victims—including Bald Eagles, Turkey Vultures, and American Crows. Cases in songbirds, though, are still uncommon. These kinds of species probably have less exposure to the virus—which often spreads via the feces of an infected bird—compared to waterfowl that gather and forage in large flocks, Harvey says. Raptors can also pick up the virus when they prey on infected birds. 

That’s why bird feeders are not a top concern at the moment, though experts emphasize that cleaning feeders regularly is crucial to prevent the spread of all kinds of avian disease. It’s also worth weighing what kind of environment your feeders are in, Harvey says, and their possible proximity to the species that are most impacted by avian flu—like poultry if you live near a farm, or shorebirds if you’re on the coast. The USDA recommends that anyone who cares for poultry “should prevent contact between wild birds and poultry by removing sources of food, water, and shelter that attract wild birds,” according to a USDA spokesperson.

If you see potential signs of illness—like “birds that are acting weirdly with a head tilted back, or walking in circles, or look disoriented”—you should keep your distance, Webby says, and wear protective equipment like gloves and a mask if you need to handle them. “Treat anything that’s sick as if it could be positive,” he suggests, even though “there’s a good chance it’s not.”

As birds gear up for another round of migration, scientists will be paying close attention to avian flu activity, though Webby says spring migration historically doesn’t bring major surges like in the fall. Looking ahead, experts say there’s a lot of work to do to better understand H5N1—including ramping up surveillance in wild bird populations and getting to the bottom of basic questions about how the virus works. This work could be crucial to the future of bird conservation, Harvey says, since it’s likely that avian flu will pose a long-term problem for wild populations. “I think that the virus is not leaving us anytime soon,” she says. “It is embedded in migratory birds.” 

Webby agrees that, while the details may differ from year to year, avian flu outbreaks will probably become an annual post-migration pattern. “What we’re seeing now, unfortunately, might very much be the new norm,” he says.