This species can be found over inshore coastal waters. Its diet varies year to year depending on availability, mainly consisting of fish and invertebrates (e.g. crabs, sea urchins) but also carrion, refuse, offal, bird eggs and chicks, voles and insects. Individuals may also take fish and roe during salmon spawning, leftovers from bear-kills, berries, and waste from fisheries and slaughterhouses. Some Hokkaido males specialise on predation, piracy and scavenging from seabird colonies but they feed their chicks mostly on fish. Prey is obtained by a varied of methods including plunge-diving and surface-plunging. Birds arrive at breeding colonies in April in the south and June in the north. Colonies form on low sea cliffs, rocky islets, sandy shores or the rocky tops of sea cliffs and can number from dozens to 1,500 pairs. Many populations are non-migratory (del Hoyo et al. 1996).

The Slaty-backed Gull breeds in north-east Siberia (Russia) from Cape Navarin south to the northern tip of North Korea, including the Commander Islands, Russia and Hokkaido, Japan. Its winter distribution extends south to encompass Korea, the extreme north-east of China, much of Japan and Taiwan (del Hoyo et al. 1996).