Wildlife rehabilitators in Michigan are not allowed to take in mute swans, the ones with the yellow beaks.
Different species of waterfowl have different emergency needs. When you see a Waterfowl in trouble it is best to not attempt to approch the bird.
The Waterfowl may my not need our help at all. Some can be dangerous such as long necked birds like herons. Contact a waterfowl rehabilitator for specific advice.