This data release includes 2 child items with tracking data for Steller's Eider, a species of seaduck that breeds throughout the circumpolar Arctic and spends the winter in coastal areas of western and southwestern Alaska. The Alaska-breeding population is listed as threatened under provisions of the Endangered Species Act. Child Item 1: "U.S. Fish and Wildlife Service Argos Satellite Tracking Data for Steller's Eiders (Polysticta stelleri) - Processed Data" -- Quality-controlled data collected from Argos satellite transmitters. Child Item 2: "U.S. Fish and Wildlife Service Argos Satellite Tracking Data for Steller's Eiders (Polysticta stelleri) - Raw Data" -- All raw data collected from Argos satellite transmitters, provided for completeness of the archive. The quality-controlled, "Argos Processed Data" (Child Item 1) are better suited for most analytical purposes.