New threats to the species, such as wind turbines or a bird flu strain, could jeopardize its long-term success. “The resilience of these animals was very close to the brink,” said Dr. Schuler. “If a few more adult breeding animals were to die, it could have a pretty big impact on the future growth of these populations.”
It is not yet clear how this bird flu will affect the recovery of the species. “I’m afraid it will be endemic, and there have already been reports of some recombination, meaning this new species is mixing with some of the North American versions that we have and creating new viruses,” said Dr. Schuler. “We always worry about that.”
According to a statement from the Georgia Department of Natural Resources, it appears the virus will hurt nesting success — a nest’s ability to produce at least one fledgling bird capable of flight — among certain populations this year. Aerial photos of nesting bald eagles in six coastal Georgia counties have shown nesting success rates have fallen 30 percent this year, the statement said.
Some wild birds infected with avian influenza may show no symptoms, but infection can also lead to neurological problems, which can make it difficult for a bird to fly or raise itself. In Back to the Wild, an Ohio rehabilitation center, bald eagles with bird flu appear to be unsteady on their feet and unable to fly; some have even had seizures.
“All are admitted with the same symptoms and die within hours of admission,” said Heather Tuttle, the center’s director of education, adding that the admission rate is beginning to slow. Of the dozens that were brought to the center, none have survived. There is no effective treatment.
Bird flu poses little threat to humans, and no cases of H5N1 bird flu infection have been reported in the United States, according to the Centers for Disease Control and Prevention. Humans should avoid direct contact with wild birds and their droppings, and hunters should avoid harvesting or handling wild birds found sick or dead. Hunters should also wash their hands with soap and water after handling game birds and cook meat to an internal temperature of 165 degrees Fahrenheit.
Some experts have advised people to remove bird feeders to reduce the spread of H5N1 in wild birds. But dr. Schuler hasn’t seen many birds using feeders, such as songbirds, that are infected with the virus. “So it doesn’t seem like that’s a major source of potential transfer,” she said.