They occur on river deltas, coastal tundra, lagoons, sea cliffs, barrier islands, and pack ice. They are scavengers as well as important predators on waterfowl and other seabirds. However, coastal glaucous gulls away from marine bird colonies feed mainly on fish. Glaucous gulls nest in colonies on sea cliffs as well as in isolated pairs on tundra ponds. Colony size is usually far smaller than that of glaucous-winged gulls.
Glaucous gulls appear on nesting territories before snow melts.
May. Clutch size is usually three eggs. Newly fledged juveniles remain with their parents close to nesting territories for several weeks after learning to fly, gradually moving to the sea in September and October. Domestic and industrial development activities on the North Slope are generating large volumes of solid waste in unnatural settings, precisely the sort of environment that facilitates explosive increases in juvenile gull survival. Artificially high glaucous gull populations will pose problems in northern and western Alaska similar to the problems abnormally high glaucous-winged gull populations present in southcoastal areas. Herring Gulls Herring gulls have white heads and bodies, gray backs, typically yellow eyes, and black wing tips with small white spots.