Each November I look forward to seeing some of my favorite birds – Tundra Swans.  More than 100,000 of these birds are just finishing their three-month migration from north of Hudson Bay in Canada to the tributaries of the Chesapeake Bay and the coast of North Carolina, where they spend their winters. A sizeable flock usually winters from November through February at the Elizabeth Hartwell Mason Neck National Wildlife Sanctuary just south of Lorton.