Bald eagle found in northwest suburbs may have died from bird flu, expert says
A bald eagle was found dead from suspected bird flu in recent days in a forested area of the northwest suburbs, another signal of how serious the disease has gotten for wild creatures as well as farm animals.
The male raptor — that may have been part of a pair of eagles that has long nested in Busse Woods just off the Jane Addams Memorial Tollway near Elk Grove Village — was found dead near the roost on Feb. 3 and subsequently tested, with the “results indicating” it had avian influenza, says Chris Anchor of the Cook County Forest Preserve District.
There’s no way to know exactly how the eagle got sick, but it’s likely the bird consumed infected prey, Anchor says.
“Right now we’re seeing it in waterfowl,” he said of the virus affecting birds. “But we’re also seeing it in great horned owls, hawks and eagles because they’ll feed on” infected ducks and the like, dead or alive.
Not only are bald eagles the national bird, but they have “made a huge comeback from the brink of extinction,” Anchor says, adding there are now six known pairs in Cook County.
Besides the pair in Busse Woods, three are near Lake Calumet on the Far South Side, and two are in the Palos area of the south suburbs.
Federal records show hundreds of dead bald eagles have tested positive for bird flu since 2022 and around the start of the outbreak, including six in Illinois, one of which was in Will County.
Many more eagles likely have died from the disease but weren’t tested, experts say.
A bald eagle found last month in Hinsdale was euthanized because it was believed to have been sick from the disease, the Chicago Sun-Times reported.
Bald eagles have had a tough go over the years, in large part because of the pesticide DDT that once was widely used.
“Shortly after World War II, DDT was hailed as a new pesticide to control mosquitoes and other insects,” according to the U.S. Fish & Wildlife Service. “However, DDT and its residues washed into nearby waterways, where aquatic plants and fish absorbed it. Bald eagles, in turn, were poisoned with DDT when they ate the contaminated fish.”
“The chemical interfered with the ability of the birds to produce strong eggshells. As a result, their eggs had shells so thin that they often broke during incubation or otherwise failed to hatch.”
By the mid-1960s, only about 400 nesting pairs of bald eagles survived, and extinction was feared, according to the wildlife agency.
Other raptors such as hawks and falcons were also significantly affected.
DDT was banned in 1972 “from most uses in the United States,” according to the U.S. Environmental Protection Agency. And in “the years following the ban, bald eagle and other bird-of-prey populations slowly recovered.”
There were more than 300,000 bald eagles in the lower 48 states as of several years ago, records show.
Krysten Schuler, director of the Cornell Wildlife Health Lab in New York, says “the eagle is our conservation success story.”
But lead poisoning has remained troublesome for the creatures, which sometimes feed on dead animals such as deer that were hunted and had fragments of lead pellets still in them. Similarly, eagles sometimes eat fish with lead tackle inside them.
“With lead poisoning it slowed the eagle recovery,” Schuler said. “Now with this additional source of mortality” — the bird flu — “it could be pretty serious.”
Anchor says the dead eagle was discovered by a visitor to the forest preserve “by pure serendipity,” and the “avian influenza and pathology” was conducted by an outside pathology group. The results “are evocative of avian influenza,” he says.
With bird flu also hitting chicken farms, egg shortages and rising egg prices have been common. The virus also has been found in mammals, including cows, and humans — raising fears it could lead to a new pandemic.