The Australian Black Swans are southern hemisphere swans, so if they are in Michigan, they are probably someone's pet that escaped and/or got blown off their course during the inclement weather you have been having. In any case, without particular care, the swans may not make it through another winter. They must be diligently cared for, brought indoors and sheltered from extreme low temperatures. Should you see them again, we would suggest that you try to feed them and get friendly with them. Then, you might be able to capture them and find them a good home so that they can be sheltered. Should you capture them and need to find a home, please contact us and we'll see if we can assist you. The Regal Swan