The article studies the behavior and condition of harlequin ducks in North America. Topics discussed include the areas populated by Pacific and Eastern harlequin duck populations, the wintering behavior of the ducks and the factors that contribute to the decline of harlequin ducks, including logging, overhunting and the construction of hydroelectric plants in rivers. Also discussed are the sources of food for the ducks and the effects of tide and time of day on their feeding patterns.