WASHINGTON – The avian influenza outbreak has wreaked havoc on poultry and dairy farms across the United States since it was first detected in North America in late 2021, leading to a spike in egg prices.
However, the impact on wild birds is a growing concern. Over 170 species of North American wild birds, including ducks, geese, gulls, owls, and eagles, have tested positive for bird flu.
Experts advise taking precautions around sick or deceased wild birds but assure that bird feeders can typically remain in use. Despite the prevalence of the virus in birds and other wildlife, scientists consider the threat to humans to be minimal at this time.
**Which Wild Birds Are Susceptible to Bird Flu?**
More than 12,000 individual wild birds have tested positive since the virus began evolving, as per the U.S. Agriculture Department. However, this number is considerably underestimated, according to Bryan Richards of the U.S. Geological Survey’s National Wildlife Health Center, since many dead birds are not submitted for testing.
Dabbling ducks, like mallards and blue-winged teal, often carry the virus with minimum symptoms, given these viruses evolved alongside waterfowl. Yet, these ducks can transmit the virus through feces or saliva, possibly affecting other avian and even mammals such as foxes.
Birds without innate immunity that cluster in large migrations or roost together, such as geese, are at higher risk of mass fatalities. For instance, a recent outbreak affected migratory eared grebes in Utah’s Great Salt Lake, killing between 15,000 and 25,000 birds. Seabirds, which tend to group in numbers, are significantly susceptible as well.
While songbirds like Northern cardinals, blue jays, or chickadees – frequent visitors to bird feeders – can get infected and perish, they appear more resilient due to their less dense congregating behavior, explains Michael J. Parr, president of the American Bird Conservancy.
**Recognizing Bird Flu Symptoms in Wild Birds**
Symptoms can differ but might include weakened movement, an inability to fly, and respiratory struggles.
“If you notice a wild bird behaving strangely, it’s best to contact a local wildlife rehabilitator and avoid handling it directly,” advises Dr. Dana Franzen-Klein, veterinarian and medical director at the University of Minnesota’s Raptor Center. If handling is necessary, using gloves and a mask for protection is advisable.
**Safety of Backyard Bird Feeders**
Experts affirm that bird feeders pose minimal risk in spreading bird flu and are generally considered safe.
However, if you have backyard chickens, Parr recommends removing feeders to prevent any potential transmission to poultry, and stresses that bird feeders and nesting boxes should be sanitized regularly. The threat of transmission to humans from bird feeders remains extremely low, he adds.
**Impact on Endangered Bird Species**
In critical endangered cases like the California condors, researchers have initiated a vaccination program post-infection. This approach, however, isn’t practical for most wild species. Instead, experts suggest bolstering habitat protection and decreasing non-virus-related risks to give birds the best survival chance. This could involve reducing pesticide exposure or eliminating lead ammunition usage.
Bald eagles, though federally protected, are no longer deemed endangered. Still, they scavenge and may ingest infected ducks or bring them for nest feeding. “Initially, many eagles likely died from eating infected prey,” recounts Richards. During the first breeding season after the virus arrived, juvenile eagle survival rates were notably low, attributed to either contracting the virus or from sickly parents unable to deliver adequate care.
Encouragingly, confirmed bald eagle infections have reduced significantly from 427 in 2022 to just 48 last year. This decline suggests surviving eagles may have developed a level of immunity, notes Franzen-Klein. Furthermore, the recent migration season registered a record number of bald eagle sightings in northern Minnesota, suggesting regional recovery.
“There are promising signs of hope for regional eagle recovery,” she affirms.
