The Collaborative International Dictionary
doucker
Golden-eye \Gold"en-eye`\ (g[=o]ld"'n*[imac]), n. (Zo["o]l.) A duck ( Glaucionetta clangula), found in Northern Europe, Asia, and America. The American variety (var. Americana) is larger. Called whistler, garrot, gowdy, pied widgeon, whiteside, curre, and doucker. Barrow's golden-eye of America ( Glaucionetta Islandica) is less common.
Wiktionary
doucker
n. 1 (context UK dialect English) A grebe or diver. 2 (context UK dialect English) The goldeneye, pochard, scoter, or other duck.