Warblers have gone south for the winter, but some sparrows remain. Careful observers may find American tree sparrows along snow lined roads, and if they are lucky, longspurs or snow buntings.
Many species of ducks, geese and swans use the refuge in winter, but their numbers are reduced compared to other times of year, because of cold temperatures and few areas of open water. Check Marshall Pond at Headquarters, the Blitzen River, Benson Pond, Knox Pond and the Narrows. Search for Barrow's and common goldeneyes, and mergansers, as well as, the rare Eurasian widgeon. One of the highlights of winter is large groups of tundra swans which are present in October and November at Knox Pond, Benson Pond and on Marshall Pond. Hundreds can gather in one area and their voices carry long distances. Resident trumpeter swans may also be seen. Both species of swans may remain through the winter, but in smaller numbers.