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 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.

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.

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.”

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.