Larus argentatus
SUBFAMILY
Larinae
TAXONOMY
Larus argentatus Pontoppidan, 1763, Denmark. Four subspecies
are recognized.
OTHER COMMON NAMES
French: Goeland argente; German: Silbermцwe; Spanish:
Gaviota Argйntea.
PHYSICAL CHARACTERISTICS
22–26 in (55–67 cm); 1.6–3.3 lb (720–1,500 g), depending
upon location. Large gull with heavy body and powerful bill;
white head, underparts, and tail; gray upperwings and mantle;
yellow bill with red gonydeal spot during breeding; pink legs
and feet. Juvenile basically gray-brown with pale spots and
blackish primaries and tail. Full adult plumage takes about four
years to fill in.
DISTRIBUTION
North America, Iceland, Faeroes, Britain to Germany and west
to northeast Siberia and China.
HABITAT
Breeds along coasts and near inland lakes and reservoirs. Wide
diversity of breeding habitats, including rocky cliffs and ledges,
grassy islands, sandy beaches and islands gravel bars, salt
marshes, and rarely in trees and on buildings. In non-breeding
season, mainly coastal and near coasts. Also forages at garbage
dumps.
BEHAVIOR
Diurnal, social, occurs mainly in flocks while foraging, and
breeds in colonies (rarely solitarily), either with conspecifics or
in mixed-species colonies. Mainly active in the early morning
and late afternoon but can also forage at night.
FEEDING ECOLOGY AND DIET
Very variable in feeding methods, feeding habitats, and prey
items. Omnivorous and highly opportunistic; diet includes fish,
earthworms, crabs, other marine invertebrates, berries, carrion,
and garbage.
REPRODUCTIVE BIOLOGY
Monogamous with long-term pair bonds, high nest-site fidelity.
Generally lays three eggs April to early June. Nest is
vegetation generally placed on the ground or a cup on bare
rock. Both sexes guard territory, build the nest, incubate the
eggs, and care for chicks. Incubation period 28–30 days.
Brooding 40–45 days. Post-fledging care of up to 45 days. First
breeding between three and seven years.
CONSERVATION STATUS
Not threatened. Increased markedly in mid-1900s due to exposed
garbage dumps and offal from fishing, decreasing in
some places with the closing of landfills. Declines in the Great
Lakes due to pollutants.
SIGNIFICANCE TO HUMANS
Eggs eaten in some places; meat seldom eaten. Feathers collected
in the late 1800s for the millinery trade. Serves a useful
scavenger role.
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