(Betsy Bloom/Daily News photo) A pair of trumpeter swans relaxes on the ice Friday at Six Mile Lake in northern Dickinson County. Trumpeter swans are among the birds that have died in Wisconsin this year from highly pathogenic avian influenza, or HPAI, also commonly called bird flu.

With spring migration firmly in gear despite this week’s winter storm, the return of seasonal birds also could bring avian influenza back to the region.

As most of the new arrivals in the Upper Peninsula travel through Wisconsin, I turned to that state’s Department of Natural Resources for information on what they’ve seen so far in terms of bird mortality from highly pathogenic avian influenza, or HPAI, also commonly called bird flu.

Jasmine Batten, a wildlife health supervisor for the Wisconsin DNR, said bird mortalities are up compared with the same period in the past two years but not as high as what was seen when HPAI really surfaced in 2022.

The deaths include hundreds of mergansers along the lower Lake Michigan shoreline in southeastern Wisconsin — the Chicago area saw die-offs in the same period — plus more than 200 Canada geese in flocks in Brown, Chippewa, Dane, Racine, St. Croix and Wood counties, according to a chart on the DNR’s Avian Influenza website, https://dnr.wisconsin.gov/topic/wildlifehabitat/disease/Avianinfluenza.

While not all of these birds were tested, avian influenza was detected in sample birds found dead or sick in those areas from December through March 17.

HPAI also was confirmed in tundra swans in Dane County, mallard ducks in Brown County and trumpter swans in St. Croix and Wood counties.

Not surprisingly, raptors likely to feed on these sick or dead waterfowl have turned up dead as well: bald eagles in Dane and Juneau counties, two peregrine falcons at a nesting site in Milwaukee, American crows in Dane and Wood counties, a red-tailed hawk in Columbia County and a barred owl in Wood County.

Only one sandhill crane death has been confirmed since December, on March 8 in the Stoughton area of Dane County. But in February HPAI killed almost 3,000 sandhill cranes in several Indiana counties, according to that state’s DNR.

Some of the cranes moving through Indiana could end up in Wisconsin and the Upper Peninsula.

While the deaths are disquieting, not all of the news points to HPAI, Batten said — 62 dead mallards found in a Little Chute detention pond in Outagamie County turned out to have succumbed to aspergillosis, a fungal disease that can be found in soil and causes lung infections.

And, for now, the most vulnerable wildlife species to HPAI are waterfowl; birds that frequent wetlands or shorelines, so come into contact with the virus through proximity; and predators or scavengers, including mammals.

Songbirds do not seem to be as susceptible, Batten said. Still, she recommends those who feed birds frequently clean their feeders, remove seed debris often, wash hands thoroughly after tending to feeders and practice safe handling if a dead bird is found, such as wearing gloves and bagging the body.

In Wisconsin, anyone who observes five or more sick or dead birds in one area is asked to contact the DNR Wildlife Switchboard by emailing DNRWildlifeSwitchboard@wisconsin.gov or calling 608-267-0866. A message should be left for the switchboard staff to return the call. The message should include the number of animals, the species, if they were sick or dead, the specific location and county where seen them and contact information.

In Michigan, reporting wildlife or wild bird diseases can be done by calling 517-336-5030 or going online to Eyes in the Field, https://www2.dnr.state.mi.us/ors/Home.

“Be aware it’s still out there,” Batten said. “We’re just not sure of what the magnitude is going to be.”

Betsy Bloom can be reached at 906-774-2772, ext. 85240, or bbloom@ironmountaindailynews.com.