Sandhill cranes are the latest victims of a particularly persistent strain of avian influenza, killing at least 1,500 of the migrating birds in recent weeks, according to a biologist with the Indiana Department of Natural Resources.
The deaths have occurred in Jasper, Starke, Newton and LaPorte counties in Northwest Indiana, as well as Greene and Union counties in the southern part of the state, and Jackson County, in eastern Indiana.
Sandhill cranes are “experiencing some large mortality events across the state right now,” said Eli Fleace, a fish and wildlife health biologist and avian health specialist with the DNR.
The strain of bird flu, formally known as avian influenza H5N1, was first found in Canada in December 2021 and in the United States in January 2022, he said, adding the strain is the same one impacting chickens and poultry farms across the country, and merganser ducks along the Lake Michigan shoreline in the Chicago area and in Whiting.
The virus has been circulating for a few years and caused “small mortality events” around the country in 2022, 2023 and for most of 2024, with what Fleace said was “15 geese here, 10 swans there.”
In December, he said biologists started to see “much, much larger mortality events” across the state and the nation, including the December death of more than 1,000 snow geese following a migratory path along the Wabash River in the western part of the state, mostly in Gibson and Vermillion counties.
Sandhill cranes fly over the Jasper-Pulaski Fish and Wildlife Area in Medaryville on Friday, December 3, 2021. The birds have been dying from avian influenza. (Kyle Telechan for the Post-Tribune)
Sandhill cranes started dying from the flu strain in early January in Jackson County, where many overwinter and feast on the remains of corn fields, Fleace said, adding at least 500 dead cranes were reported to the DNR there.
By late January, as sandhill cranes began to migrate from the south to Northwest Indiana and Michigan, “a lot of those cranes had influenza.” Many of those birds migrated from Tennessee, Florida and Alabama.
“This year they brought avian influenza with them and it just ripped through the population very quickly,” Fleace said, adding 1,500 dead sandhill cranes have been reported to him. “That’s likely an underestimate. There’s birds that die that nobody sees,” or people see them and don’t report them.
Because of limited resources, Fleace said the DNR can’t test every bird but there’s only been one sandhill crane he tested that didn’t have avian influenza and he suspects that was a false negative.
“On a smaller scale, humans really can’t do much in a single season,” he said, adding the virus thrives in cold weather and birds are migrating in large flocks. “You can’t ask them to isolate from each other.”
Carcass disposal of dead birds might remove the virus from the landscape, Fleace said, but not the living bird population.
That also has its own risks, though they are limited.
“We do ask that you avoid contact with waterfowl because this is a zoonotic disease. A zoonotic disease is a disease that can spread from animals to humans,” Fleace said.
Anyone who chooses to remove dead birds should wear a mask and gloves, double-bag the carcass, wash their hands and disinfect their clothes, he said.
Sandhill cranes congregate on a field at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana on Wednesday, Oct. 23, 2019. The birds are dying from avian flu. (Kyle Telechan for the Post-Tribune)
According to a Jan. 6 release from the federal Centers for Disease Control and Prevention, one person in Louisiana died from avian influenza and “there have been 66 confirmed human cases of H5N1 bird flu in the United States since 2024.”
Outside the U.S., more than 950 cases of H5N1 bird flu have been reported to the World Health Organization and about half of those have resulted in death, according to the CDC.
“Most importantly, no person-to-person transmission spread has been identified. As with the case in Louisiana, most H5 bird flu infections are related to animal-to-human exposures,” the CDC said.
The virus, Fleace with the DNR said, is more deadly in domestic poultry because they don’t have the same immune systems as birds living in the wild, and even the risk to humans “is very low.”
The greater concern with transmission to humans, he said, is that the more people who get the virus, the more chance there is that the virus could mutate and become something worse.
Anyone who finds a dead bird is asked to report it online at on.in.gov/sickwildlife. They might not get a response because the DNR is getting so many reports, Fleace said, but the reports help him keep track of the numbers.
The arrival of spring should decrease the number of deaths, too.
“We’re expecting them to taper off as the weather warms up,” Fleace said.
alavalley@chicagotribune.com
