Science & Nature
Bird Flu Claims a Bald Eagle Victim in a Cook County Forest Preserve, Sandhill Cranes Are Dying Too
(U.S. Fish and Wildlife Service)
Bird flu is believed to have caused the death of a bald eagle found earlier this month in the Busse Woods forest preserve, according to officials.
The lifeless eagle was reported by a visitor to the northwest suburban preserve. Cook County forest preserve wildlife staff then collected the bird from the ground near its roost and submitted it for testing, Carl Vogel, forest preserve spokesperson, told WTTW News.
“The results give all indications that the bird died of (highly pathogenic) avian influenza,” Vogel said, though the official designation still awaits federal confirmation.
The bald eagle is the latest victim of a strain of deadly bird flu that has been circulating since 2022 and has killed more than 150 million poultry and an untold number of wild birds. The Chicago region has seen waves of die-offs, from geese in December to hundreds of merganser ducks washing up on the lakefront at the beginning of February.
Wildlife advocates have been raising the alarm for months that the latest outbreak, which seems to be more virulent than past strains, was likely to spread outside of populations of ducks and geese, which are known reservoirs for the virus.
They pointed to the large number of infected carcasses left uncollected, as die-offs have outpaced resources to dispose of them. Eagles and other raptors, advocates warned, would be vulnerable to infection themselves if they fed on the carcasses.
Because there’s no way of knowing how many dead wild birds are never found, and there’s limited capacity to test for the virus in birds that are found, experts say the death toll is likely massively undercounted.
In recent weeks, though, reports have begun to mount.
Michigan wildlife officials suspect avian influenza as the cause of death in hundreds of birds (mostly geese) collected in just five counties.
Likewise, officials in Milwaukee and Indiana have confirmed bird flu deaths among waterfowl. Sadly, for Chicagoans who thrilled at the sight and sound of migrating sandhill cranes just a few months ago, hundreds have died from the virus on their journey south. As many as 150 of the cranes were found dead in Tennessee alone, but deaths have also been reported in Indiana and Kentucky.
The current cold snap could increase infections, as colonial birds cluster together on smaller areas of unfrozen water.
Vogel of Cook County forest preserves said disease surveillance and testing for avian influenza is a priority, given the rise of cases across the region and country.
Vaccine May Be on the Horizon for Chickens
Relief may be on the way for poultry farmers, who have seen their flocks, and bottom lines, devastated by the outbreak.
Late last week, the company Zoetis announced it had received a conditional license for its avian influenza vaccine from the U.S. Department of Agriculture Center for Veterinary Biologics. The vaccine is labeled for use in chickens.
Zoetis notably also developed a COVID-19 vaccine that was distributed to zoos and aquariums during the pandemic.
Avian influenza vaccines for poultry have been controversial, largely due to concerns that vaccinated birds could harbor the disease. It is up to regulators to determine whether flocks will be vaccinated.
Human Spread May Be Wider Than Thought
A new report from the Centers for Disease Control and Prevention suggests H5N1 (the circulating bird flu) could be more widespread among humans than previously thought.
Blood samples drawn from 150 veterinarians — specifically targeting those that treated cattle — revealed three instances where antibodies to avian influenza were present, in individuals who had not been diagnosed with the virus. None of the three had even reported experiencing any flu-like symptoms.
Nor had any of the three treated cattle with known H5N1 infection (a mutation of the virus jumped to cattle in 2024). One of the veterinarians worked exclusively in states where no H5N1 infections had been reported in any cattle herds.
Among the report’s conclusions: By focusing surveillance efforts solely on people with reported symptoms, infection rates in humans are likely to be underestimated.
Recommendations included continued outreach to people at risk of exposure, veterinarians among them.
Contact Patty Wetli: @pattywetli | (773) 509-5623 | [email protected]
