Larus appears to have referred to a gull or other large seabird, and fuscus meant black or brown.

The bill is yellow with a red spot at which the young peck, inducing feeding (see fixed action pattern).

Identification from juvenile herring gulls is most readily done by the more solidly dark (unbarred) tertial feathers.

The species has not yet bred in the United States, although hybrid pairs with American herring gulls have been recorded twice.

[2] This species breeds colonially on coasts and lakes, making a lined nest on the ground or a cliff.

[11] They are omnivores like most Larus gulls, and they eat fish, insects, crustaceans, worms, starfish, molluscs, seeds, berries, small mammals, eggs, small birds, chicks, scraps, offal, and carrion.