Several dozen waterbirds, primarily snow geese, died earlier in December at Baldwin Lake State Fish and Wildlife Area in southern Illinois, and dead waterfowl have been found more recently in northern Illinois, state officials said. The bird deaths were likely due to a highly infectious and deadly strain of bird flu called HPAI.

Specific numbers and species of birds that likely contracted the disease in northern Illinois are not yet available. Health officials are asking the public not to handle sick waterfowl or other wild birds that appear ill and not to take them to wildlife rehabilitation centers.

Brad Semel was conducting a bird count in mid-December in Kenosha County just over the Illinois border when he noticed several dead geese frozen in a lake and some smaller ponds. “I assumed they were just from a cold snap,” said Semel, endangered species recovery specialist for the Illinois Department of Natural Resources.

But then he learned these geese likely died of avian flu. “There are a number of significant events like this taking place in Cook, Lake and McHenry Counties,” Semel said.

“The flu started in southern Illinois a few weeks ago and began moving north,” Semel said. “It’s impacting mostly geese, but some cranes, herons and eagles.”

Adam Sell, a Gurnee resident and birder, said he was out watching birds Wednesday when he encountered “a lot of dead waterfowl around the edge of the ice on Third Lake.”

“It was mostly Canada geese, but there were some other smaller birds, likely ducks, that were also dead. It wasn’t just one or two,” said Sell, who logged his findings on eBird, a free web-based tool for reporting bird observations.

Dead geese were also recently reported in DeKalb County. Last week, officials from Oaken Acres Wildlife Center in Sycamore said they will no longer accept geese that exhibit symptoms of the flu.

As more dead birds are reported, it’s highly likely their deaths are the result of the spreading avian influenza, according to the Illinois Department of Public Health, Illinois Department of Agriculture and IDNR, which issued a joint statement Friday.

Tests are being conducted on some of the birds.

“While it is unlikely that handling dead birds would lead to human infection, it is best to be cautious,” according to the statement.

The statement said if people find five or more dead birds on their property, they should call the U.S. Department of Agriculture Wildlife Services at 866-487-3297 or contact a district biologist with the IDNR.

Wild aquatic birds including ducks, geese, swans and gulls can carry and spread the virus, often without showing symptoms of becoming sick.

Poultry flocks and backyard chickens have become infected, with more than 125 million birds killed or euthanized across the country since the outbreak began in 2022.

The Centers for Disease Control and Prevention said the avian flu is causing outbreaks in poultry and dairy cows and that there have been 64 confirmed human cases of the disease in the United States in 2024. None were in Illinois, and most occurred in California. The first severe human case was reported Dec. 13 in Louisiana, according to the CDC.

Officials said anyone who develops symptoms such as fever, cough, difficulty breathing, headaches, vomiting or diarrhea after exposure to sick or dead birds should contact his or her local health department immediately.

Treatment must be started within two days of illness for it to be most effective, according to the IDPH.

“While avian influenza generally poses a low risk to the population, it is essential to take the necessary steps to avoid exposure and to seek treatment quickly if you are exposed,” said IDPH Director Sameer Vohra.

“We encourage all Illinoisans to follow the advice of the experts at IDNR in order to avoid contact with sick birds, and to take any potential exposure seriously,” Vohra said.

“These common-sense steps can help reduce the likelihood of spreading this illness.”