Fewer bald eagle chicks are fledging due to bird flu

Bald eagles are often touted as a massive conservation success story due to their rebound from near extinction in the 1960s.

But now a highly infectious virus may jeopardize that hard-fought comeback.

Posted in Nature Science Reportsnew research from the University of Georgia has shown that highly pathogenic avian influenza, also known as H5N1, is killing an unprecedented number of bald eagle pairs.

“Even a single year of productivity losses, as we have documented at the regional level, is very concerning and could have effects for decades if representative of wider regions,” said Nicole Nemeth, lead author of the report. study and associate professor in the College of Veterinary Medicine. “There were nights I couldn’t sleep because of what we were hearing and seeing. We have already lost unprecedented numbers of wild birds to this virus in the United States and it looks like it is here to stay.

Less than half of Georgia’s bald eagle nests gave birth to a chick in 2022

Researchers found that just under half of bald eagle nests along the Georgian coast succeeded in fledging at least one eaglet in 2022. That’s 30% below the region’s average.

The study also showed that the nest success rate was halved in one Florida county to 41% from an average of 86.5%. Another Florida county saw a less dramatic but still concerning drop, from an average of about 78% to 66.7%.

“We have had reports of people who faithfully monitor eagle nests year after year with these heartbreaking stories of an adult eagle found dead under their nest. Within a few days, often her mate and the chicks were also found dead under the nest. Clearly the virus is causing nest failures,” said Nemeth, who is part of the UGA-based Southeastern Cooperative Wildlife Disease Study (SCWDS).

The collaboration is the first diagnostic and research service established specifically to investigate wildlife diseases.

The number of infected wild birds is probably underestimated

In April 2022, SCWDS researchers confirmed that highly pathogenic avian influenza had struck Georgia eagle populations for the first time.

The three dead eagles were found in Chatham, Glynn and Liberty counties in March.

At the time, the United States Department of Agriculture (USDA) had confirmed about 660 cases of the H5N1 virus in wild birds, of which only 11 were from Georgia.

That number has since skyrocketed to more than 6,200 reported cases nationwide, according to the USDA’s Animal and Plant Health Inspection Service.

These cases include a variety of vultures and other raptors, waterfowl like geese and ducks, as well as other waterfowl like pelicans and herons, and even some songbirds, although they are casualties. less frequent of the virus. (Tens of millions of commercially raised poultry have died or been culled due to the risk of infection.)

“I think the number of wild bird cases is significantly underreported,” Nemeth said. “People will submit a Snow Goose, for example, and it will test positive for the virus. And then they’ll tell you, ‘Well, there are thousands of geese dying on the same site.’ But it only comes down like an infected bird.

H5N1 does not pose a massive threat to humans, but may do so to other species

The birds most at risk of infection are those that live in coastal areas or other inland water areas or feed on other birds that live there.

The virus can persist in water for over a year under the right conditions. Although not a risk to humans, birds can pick up the virus by spending time in water and transport it to new places through migration.

Raptors like eagles and vultures then catch the virus when they eat the infected birds.

“Worst-case scenario, we’re going into a scary place with some of these bird species,” Nemeth said. “We could see a lot more decline in numbers of eagles, raptors, waterfowl and other birds than we have already seen. It could be devastating.

Bears, red foxes and coyotes among animals infected with virus

Bird flu also jumped species.

H5N1 has infected wild mammals like red foxes, coyotes, raccoons, seals, possums and bears in North America. However, very few people have been infected with the virus in the United States and have recovered with minimal symptoms, according to the Centers for Disease Control and Prevention.

“A virus that can spread and sustain itself like this virus can, it’s everywhere now,” Nemeth said. “We cannot contain the virus and we cannot vaccinate wild birds. But we can document losses and try to help conserve affected species and populations as best we can.

The study was co-authored by Mark Ruder, Rebecca Poulson and David Stallknecht from the University of Georgia. Additional co-authors include Robert Sargent of the Georgia Department of Natural Resources, Shawnlei Breeding of Audubon’s EagleWatch, Meaghan Evans, Jared Zimmerman, Rebecca Hardman, Mark Cunningham of the Florida Fish and Wildlife Conservation Commission, and Samantha Gibbs of US Fish & Wildlife.

Thanks to the University of Georgia for providing this news.

The current strain of bird flu is probably ‘here to stay’