Gaviota Californiana

Identificación

Adults are similar in appearance to the herring gull, but have a smaller yellow bill with a black ring, yellow legs, brown eyes and a more rounded head. The body is mainly white with grey back and upper wings. They have black primaries with white tips. Immature birds are also similar in appearance to immature herring gulls, with browner plumage than immature ring-billed gulls. Length can range from 46 to 55 cm (18 to 22 in), the wingspan 122–137 cm (48–54 in)[citation needed] and body mass can vary from 430 to 1,045 g (0.948 to 2.304 lb).

Taxonomía

Nombre científico

Larus californicus

Autoridad

Lawrence, 1854

Orden

Charadriiformes

Familia

Láridos

Género

Larus

Distribución y hábitat

Their breeding habitat is lakes and marshes in interior western North America from the Northwest Territories, Canada south to eastern California and Colorado. They nest in colonies, sometimes with other birds. The nest is a shallow depression on the ground lined with vegetation and feathers. The female usually lays 2 or 3 eggs. Both parents take turns feeding their chicks.<p>They are migratory, most moving to the Pacific coast in winter. It is only then that this bird is regularly found in western California.

Área de cría

NA : c Northwest Territories to c Manitoba (c Canada) to ne South Dakota; e Washington to Montana and s to Colorado and c California

Área no reproductiva

e North Pacific coast from s British Columbia (sw Canada) to wc Mexico

Migración

Complete migrants

Comportamiento

These birds forage in flight or pick up objects while swimming, walking or wading. They mainly eat insects, fish and the eggs and young of other birds, especially ducklings. Opportunistic feeders, they also scavenge at garbage dumps, marinas and docks. They frequently beg for food at public beaches, parks and other locations where people will hand feed them. They have been known to steal food directly from people at picnics and outdoor restaurants. They may follow fishing boats or plows in fields for insects stirred up by this activity.<p>California gulls are also known to eat various vegetables and fruits, particularly cherries. As a result, in some areas it may be regarded as a crop pest.

Conservación

Tendencia poblacional

declining