Every autumn large flocks of ducks gather in the Lake Huron waters at the North end of the Mackinac Bridge. Rafts of thousands can be seen when northbound on the bridge. The vast majority are Redheads but study of photos usually show a few Canvasbacks and Scaup in the mix. They are often so tightly packed that they appear as dark smudges on the water. These rafts will remain until ice up and can be a spectacular show when taking to the air. Already this October there are at least a few thousand present with more to come.
