Avian influenza is killing an alarming number of bald eagles and other wild birds, with many sick birds arriving at rehabilitation centers unsteady on their claws and unable to fly.
“It’s a wonderful sight to see a six-foot-tall eagle having uncontrollable fits of highly contagious avian influenza,” said Victoria Hall, executive director of the University of Minnesota’s Raptor Center. “At this point, they are so far ill and have no treatment options left.”
The latest outbreak of the highly contagious virus has killed nearly 37 million chickens and turkeys on US farms since February, and the USDA has confirmed 956 cases of bird flu in wild birds, including at least 54 bald eagles. But the actual number is likely much higher because not every wild bird that dies is tested and the federal census does not include cases recorded by wildlife rehabilitation centers.
The latest reported toll is about 10 times higher than the 99 confirmed cases in wild birds during the last bird flu outbreak in 2015. This time, the virus was detected in birds in 34 states, indicating that it is much more widespread than it was seven years ago. .
The US Geological Survey’s National Wildlife Health Center also collects data from wildlife officials on suspected and confirmed deaths from bird flu. It lists 8,536 recent deaths of wild birds from bird flu.
“This is certainly an unprecedented event,” said researcher Rebecca Paulson, who has been studying bird flu for 15 years at the Southeastern University of Georgia Collaborative Wildlife Disease Study. “The number of birds and species and cases in which they have already been detected is alarming.”
Waterfowl including ducks and geese, which usually carry the virus, and raptors and litter that feed on it are the most common, but cases have been confirmed in more than thirty species. Ducks and geese are usually able to live with the virus without getting sick, but the latest version is proving to be much more contagious and more deadly.
“We’re seeing a massive impact of this virus,” said Hall, whose Raptor Center in St. Paul, Minnesota, treats nearly 1,000 birds a year. “We see birds coming in with this virus every day.”
Nearly 61% of the 188 birds the rehabilitation center has tested since late March have had bird flu and all but one have died. Hall said the center had to set up an area where workers in protective gear would test sick and infected birds with bird flu and put them in quarantine before bringing them to the center, to avoid infecting other birds.
None of the 114 positive cases the center recorded, including 28 bald eagles, were included in the USDA count, Hall said. She said a large horned owl has recovered from the virus, which gives her hope that some wild birds may be able to fight it off.
USDA officials did not respond to questions about why they excluded data from rehabilitation centers.
In a study published three years ago, scientists estimated that the number of wild birds in North America has declined by about 3 billion since 1970 as humans continue to encroach on their habitat. But it’s too soon to know the impact of bird flu on birds because the outbreak is ongoing and there hasn’t been enough time to study it, according to US veterinarian Samantha Gibbs, and other experts.
“We are very concerned,” Gibbs said. “I think we’ll be watching carefully the death rates throughout the spring and summer.”
Gibbs and Paulson said they fear the virus could survive into the summer, when it usually dies, bringing the infection down when migratory birds return south. It happened in Europe where the virus first spread.
Bald eagles – the national symbol of the United States since the 18th century – are among America’s most famous conservation success stories. With an estimated 300,000 bald eagles in the country today – a population that quadrupled between 2009 and 2021 – the bird was removed from the endangered species list in the United States in 2007. Given this, experts believe the species must overcome effect of this virus.
State and federal officials will track the vultures’ nesting success in the spring and summer to gauge the impact of the virus.
In Georgia, where three bald eagles who died have tested positive for bird flu, the state’s Department of Natural Resources has documented a sharp decline in bald eagle breeding this year in six coastal counties where many migratory birds spend the winter. Less than half of the 73 nests found there produced offspring, while nests elsewhere in the state had a success rate close to the 78% average recorded in recent years.
Some experts, including Hall, suggest that residential bird feeders should be removed to avoid further spread of the virus, but the USDA and the US Fish and Wildlife Service have not recommended this because bird flu is not uncommon among songbirds that frequent backyards. However, they say it is important to clean bird feeders regularly to help reduce the spread of other diseases.
“The wild birds could use all the help they can get now,” Hall said.
When the virus is found on poultry farms, officials slaughter entire flocks to limit its spread, even when most birds have no symptoms. To date, 37.36 million birds have been killed in 32 states.
USDA officials stress that bird flu does not jeopardize food safety because infected birds are not allowed into the food supply, and properly cooking poultry and eggs to 165 degrees Fahrenheit will kill any viruses or bacteria.
Health officials also say bird flu does not present a significant health risk to people, although one human case of the disease was confirmed in Colorado last month. Officials say people are unlikely to contract the virus unless they have prolonged direct exposure to infected birds.
Confirmation of two cases of bird flu in zoos in the United States with the spread of the virus
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