Scratch,
Geese and Ducks are migratory birds protected by both State and Federal law in Michigan.
http://www.michigan.gov/dnr/0,1607,7-153-10363_10859-31034--,00.html
Rather than calling the police, as some have suggested, I would call the Department of Natural Resources and ask for clarification on whether the neighbor can feed these gamebirds legally. In addition, if the area where your dad lives is zoned, can the City's zoning regulations address the problem
This doesn't seem to be a police matter, but that's just my take based on the limited information here.