Investigators said initial signs indicated one snowmobiler crossed the frozen portion of Fond du Lac River and skipped across the area of open water, hitting and killing ducks wading in the open space, the Milwaukee Journal Sentinel said Wednesday.
Department of Natural Resources warden supervisor George Protogere said signs at the scene of the crime indicated the unidentified snowmobiler made more than one pass at the wading ducks Tuesday.
The incident came mere days after a group of snowmobilers in Waupaca County herded several deer together before striking the animals with their vehicles.
That incident left four deer dead and forced the euthanization of a fifth deer, the Journal Sentinel said.
Association of Wisconsin Snowmobile Clubs President Bill Schumann has already condemned such snowmobile actions.
"It's disgusting. I don't know what's going on out there, what people are thinking. There's something drastic going wrong here," he said. "This is not what snowmobiling is all about."