Migratory waterfowl are still in Canadian and Alaskan nesting grounds this time of the year. The ducks you are seeing now are those that seldom leave this area and are considered local birds. That's why you see some now but many more in the winter.
Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘...Holy Crap ...What a ride!'