Primary upland nesting species include the mallard, pintail, gadwall, and American wigeon. Winter visitors include brent geese, wigeon, pintail and many species of wading birds. Thousands of Eurasian wigeon, northern pintail, northern shoveller also use the backwaters. Commonly seen birds include the great egret, osprey, towhee, mallard, pintail, white-crowned sparrow and dowitcher. Breeding ducks include long-tailed duck, northern pintail, and green-winged teal. Waders include Redshank, Black-tailed godwit, Dunlin, Pintail and Turnstone. They are northern pintail, white-winged tern, Eurasian curlew, Eurasian whimbrel, godwits, and ruddy turnstone. Ducks, the South Georgia pintail and Eaton's pintail, inhabit South Georgia, Kerguelen and Crozet. There is also an endemic subspecies of the duck Eaton's pintail. Many pintail and other ducks feed and rest in the estuary. Pintail snipes migrate here flying to from Siberia. A leucistic (whitish) variant is known in aviculture as the Silver Bahama pintail. The white-cheeked pintail feeds on aquatic plants and small creatures obtained by dabbling. Pintail served in the Royal Navy as the boatswain aboard HMS "Falcon Rover". The sloop HMS "Pintail" was badly damaged escorting FS 323.