Slaty-backed Gull Life History

Habitat

Slaty-backed Gulls are primarily a coastal species. They breed on sea cliffs, small rocky islands, and sandy beaches; and they regularly forage at fishing ports and fish-processing plants. They sometimes move inland along rivers to feed on spawning salmon. Some birds in Kamchatka, Russia, breed on islands in freshwater lakes.

Food

Slaty-backed Gulls feed mainly on fish and marine invertebrates such as crabs and sea urchins, but they also consume carrion, garbage, the eggs and chicks of other bird species, and even crowberries in late summer. Depending on their prey, they may catch food by plunging into the water or by dipping underwater while swimming. Some Slaty-backed Gulls specialize in raiding seabird colonies, where they take adult and young alcids and Black-tailed Gull chicks.

Nesting

Nest Placement

Placed on the ground, often in thick vegetation or between large rocks.

Nest Description

A large, messy cup made of grass, seaweed, and feathers.

Nesting Facts

Behavior

Slaty-backed Gulls are adaptable, opportunistic birds. They take advantage of feeding opportunities at fishing ports and fish-processing plants, and even nest on rooftops on the Japanese island of Hokkaido. They breed in dense colonies, often with two nests per square meter. Incubation lasts about 30 days, and then the parents feed chicks for 40–45 days.

Conservation

IUCN lists Slaty-backed Gull’s conservation status as Least Concern. The population size and trend are unknown but are not believed to warrant a higher level of conservation concern.

Credits

Adriaens, P., M. Muusse, P. J. Dubois, and F. Jiguet (2022). Gulls of Europe, North Africa, and the Middle East: An Identification Guide. Princeton University Press, Princeton, NJ, USA.

Brazil, M. (2009). Birds of East Asia: China, Taiwan, Korea, Japan, and Russia. Christopher Helm, London, UK.

Burger, J., M. Gochfeld, E. F. J. Garcia, and G. M. Kirwan (2020). Slaty-backed Gull (Larus schistisagus), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.slbgul.01

Grant, P. (1997). Gulls: A guide to identification. San Diego: Academic Press.

Malling Olsen, K., and H. Larsson. (2003). Gulls of North America, Europe, and Asia. Princeton University Press, Princeton, NJ, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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