A massive group of dead waterfowl that washed up along the southern shores of Lake Michigan near Chicago and its northern suburbs is believed to be linked to the ongoing bird flu outbreak, wildlife officials said this week.
The majority of the waterfowl were red-breasted mergansers, a diving duck also known as the sawbill. Other duck species and Canada geese also were among the victims. The warmer weather and melting ice along Lake Michigan, which has opened up new areas of water, likely contributed to the large number washing up on shore, according to the Illinois Department of Natural Resources.
Reports of the dead birds first surfaced over the weekend. Chicago Bird Collision Monitors, a volunteer conservation group, began receiving reports Jan. 31 of large numbers of mergansers found along the lakefront. The bird organization told NBC 5 Chicago that around 200 to 300 infected mergansers were reported between Friday and Sunday.
The sight of ducks floating in the water and being disoriented in nearby parking lots is not only tragic, but the sheer scale of the die-off has also raised alarm among bird groups and wildlife lovers.
While it’s shocking to see a massive die-off, it’s not uncommon for birds that travel in such large populations, said Matt Igleski, executive director of Chicago Bird Alliance. Igleski said it’s also becoming more common to see these events in Lake Michigan as climate change, namely the lack of ice during the winter, causes more waterfowl to overwinter in the area.
He cautioned that there likely will be more die-offs as the bird flu outbreak continues.
The bird deaths on Chicago’s shores also prompted the Milwaukee County Zoo to close its aviary “out of an abundance of caution.” In an announcement, the zoo said the closure would last “for the foreseeable future.”
The bird flu has been detected in humans, but as the outbreak worsens, cases may be hard to track. The Trump administration has paused most federal health agency communications, including the release of the Center for Disease Control and Prevention’s Morbidity and Mortality Weekly Report, a trusted source of public health data.
Bird flu spreading in wild birds across the U.S.
Between Dec. 29, 2024, and Jan. 17 of this year, there were 65 new detections of the highly pathogenic avian influenza in wild birds across 20 states, according to data published by the U.S. Department of Agriculture on Jan. 31.
Wild birds can carry the virus without showing symptoms, enabling them to spread it to new regions and potentially expose domestic poultry. In fact, ducks are great hosts for the bird flu to spread, and even create new strains. That’s because ducks don’t always get very sick from many bird flu strains. Ducks can often still fly, eat and mingle with other birds, spreading these new viruses to other animals.
Waterfowl also congregate in large, mixed flocks that can worsen disease spread, Igleski said.
California Gov. Gavin Newsom declared a state of emergency after the virus was detected in dairy cows on farms in Southern California. And a new strain of avian flu, H5N9, was recently discovered on a duck farm in California that experienced an outbreak of the more common H5N1 flu last fall.
Officials in Pennsylvania and New York have killed thousands of wild geese and commercial poultry flocks after finding cases of the flu. Last week, Massachusetts health officials said the bird flu is likely widespread in the state even in areas without confirmed positive cases. The outbreak has also caused a shortage of eggs, which has driven up prices, according to the USDA.
Bird flu detected in humans
Wisconsin identified its first human case of bird flu on Dec. 18, 2024, in a worker at a Barron County turkey farm. The farmworker had relatively mild symptoms and was on a road to full recovery with antiviral medications, officials said later that month. Wisconsin is among 10 states to report human cases of the virus, but bird flu risk in Wisconsin remains low, according to the Wisconsin Department of Health Services.
As of Jan. 13, the Wisconsin Department of Agriculture, Trade and Consumer Protection had detected avian influenza in commercial poultry flocks in Burnett and Barron Counties and in a backyard flock in Kenosha County.
More:Bird flu found on a turkey farm in Burnett County, Wisconsin: What to know
What should I do if I see a sick bird?
Human cases of bird flu in the U.S. have almost all been among people in direct contact with infected cattle and poultry. According to the Wisconsin Department of Natural Resources, the majority of avian influenza viruses do not infect humans.
However, simple precautions should be taken to minimize the risk of infection, such as:
Do not handle sick or dead wild birds, even to transport them to a veterinarian or refuge.Wash hands thoroughly with soap and water after contact with a wild bird or contaminated surfaces, which includes birdbaths and feeders. Wear disposable gloves when cleaning bird feeders and baths. Common disinfectants, including detergents, 10% bleach solution and alcohol can be used to inactivate the virus.Cook all meat, including wild birds and poultry, thoroughly to 165° F to kill organisms and parasites.Hunters should sanitize all tools and surfaces when handling, cleaning and preparing wild birds.
More:First presumptive human case of bird flu reported in Wisconsin
Contributing: Anthony Robledo, USA TODAY
