Sea ducks include the 15 North American species within the tribe Mergini. This diverse group of waterfowl represents 1/3 of all NA waterfowl species. Adapted to life at sea they spend most of the year in coastal marine environments when not nesting or brood rearing. Sea ducks have deferred sexual maturity, low annual recruitment, and variable breeding rates. Population stability is maintained through high adult survival. Several populations show long-term declines but causes have not been identified. Spectacled (Somateria fischeri) and Steller's (Polysticta stelleri) eiders are listed as threatened species. Other species of concern are king (S. spectabilis) and common (S. mollissima) eiders, scoters (Melanitta spp.) and long-tailed ducks (Clangula hyemalis). We have used satellite telemetry to help understand seasonal movements and distribution of several species including surf (M. perspicillata), white-winged (M. fusca), and black (M. nigra) scoters, Steller's eiders, and harlequin ducks (Histrionicus histrionicus). These species will be used to discuss the use of satellite transmitters and illustrate a diverse array of life history and migration strategies.