Distributional and dietary responses of wintering Steller’s Eiders (Polysticta stelleri) to spring spawning of Baltic Herring (Clupea harengus) were studied along the Lithuanian coast of the Baltic Sea. Herring spawn is patchy, but is abundant and energy-rich when present. The objective of this study was to determine whether Steller’s Eiders modified their foraging sites and food habits to take advantage of spawn, or whether they were inflexible foragers as suggested by earlier studies. Steller’s Eiders altered their habitat use during herring spawn, moving to habitats where fish spawning occurred. Also, diet analysis demonstrated that herring eggs became an important food when available. Although the importance of herring spawn for Steller’s Eiders remains speculative, this study indicates that spawning sites could be important as a source of nutrients and energy for subsequent migration or reproduction, and should receive conservation consideration.