Bird Flu’s Impact on Wild Birds: What You Need to Know
WASHINGTON (AP) — Since its arrival in North America in late 2021, bird flu has wreaked havoc on poultry and dairy farms, driving egg prices to record highs. But what about its toll on wild birds?
More than 170 species of North American wild birds—including ducks, geese, gulls, owls, and eagles—have been affected by the virus. Experts advise taking precautions around sick or dead birds, but there’s no need to remove backyard bird feeders. While bird flu continues to spread among wildlife, scientists say the risk to the general population remains low.
Which Wild Birds Are Affected?
Since the outbreak began, over 12,000 wild birds have tested positive for bird flu, according to the U.S. Agriculture Department. However, this is likely a “gross underestimate,” as most dead birds are never tested, says Bryan Richards from the U.S. Geological Survey’s National Wildlife Health Center.
Dabbling ducks, such as mallards and blue-winged teal, often carry the virus without symptoms because they have co-evolved with it. However, they can still spread it through their saliva and feces, infecting other birds and even mammals like foxes.
Birds with no natural immunity, especially those that migrate or roost in large flocks, are at higher risk of mass die-offs. For example, an outbreak in Utah’s Great Salt Lake region recently killed between 15,000 and 25,000 eared grebes. Seabirds, which nest in dense colonies, are also highly vulnerable.
While songbirds like cardinals, blue jays, and chickadees can contract the virus, their populations fare better because they don’t gather in large groups where transmission is more likely, explains Michael J. Parr, president of the American Bird Conservancy.
What Are the Symptoms of Bird Flu in Wild Birds?
Symptoms can vary but often include lack of coordination, difficulty flying, and respiratory distress.
“If you see a wild bird acting strangely, the best course of action is to contact a local wildlife rehabilitator and avoid handling it directly,” says Dr. Dana Franzen-Klein, veterinarian and medical director at the University of Minnesota’s Raptor Center.
If handling is necessary, wearing gloves and a mask is advised.
Is It Safe to Keep a Backyard Bird Feeder?
Experts say bird feeders are generally safe and not a significant source of bird flu transmission. However, those with backyard chickens should consider removing feeders to prevent potential cross-contamination. Regular cleaning of bird feeders and nesting boxes is also recommended.
“The risk of transmission to humans from bird feeders is very, very low,” says Parr.
How Is Bird Flu Impacting Endangered Bird Species?
For critically endangered California condors, scientists have launched a vaccination program after several birds were infected. However, mass vaccination isn’t feasible for most wild species. Instead, conservationists stress the importance of protecting natural habitats and reducing other threats, such as pesticide exposure and lead poisoning.
Bald eagles, though no longer endangered, were heavily impacted in the first year of the outbreak. Many likely contracted the virus by scavenging infected ducks, leading to high mortality rates and an unusual drop in chick survival.
However, the number of confirmed eagle infections has significantly declined, from 427 cases in 2022 to just 48 in 2023. This suggests that surviving eagles may have developed some immunity, says Franzen-Klein. Encouragingly, researchers recently recorded a record number of bald eagles migrating through northern Minnesota.
“There are good signs of hope,” she says, as eagle populations appear to be rebounding.