Gaviota Australiana

Identificación

The head, body, and tail of an adult silver gull are white, and the wings are light grey with white-spotted, black tips. Adults range from 40–45cm (15-17 Inches) in length. Their wingspan ranges from 271 to 314mm (10-12 Inches). Adults have bright red beaks which gets brighter during breeding or when they get older.<p>Juveniles have brown patterns on their wings, and a dark beak.

Taxonomía

It has traditionally been placed in the genus Larus, as is the case with many gulls, but is now placed in the genus Chroicocephalus. Hartlaub's gull (C. hartlaubii) of South Africa was formerly sometimes considered to be subspecies of the silver gull.[citation needed]<p>There are three subspecies:

Nombre científico

Chroicocephalus novaehollandiae

Autoridad

(Stephens, 1826)

Orden

Charadriiformes

Familia

Láridos

Género

Chroicocephalus

Distribución y hábitat

Silver gulls are found in all states of Australia, as well as New Zealand and New Caledonia. It is a common species, having adapted well to urban environments and thriving around shopping centres and garbage dumps. Their successful adaption to urban habitats have seen their population increase in areas of human activity, with the availability of nesting grounds the only limiting factor on population growth.<p>Silver gulls have twice been recorded in the United States; one bird was shot in August 1947 at the mouth of the Genesee River, Lake Ontario, and another was photographed in Salem County, New Jersey, in autumn 1996. Both are believed to have escaped from captivity.

Migración

Complete migrants

Comportamiento

The silver gull has a sharp voice consisting of a variety of calls. The most common call is a harsh, high pitched 'kwarwh'.<p>The silver gull naturally feeds on worms, fish, insects and crustaceans. It is a successful scavenger, allowing increased numbers near human settlements. It is known to pester humans for scraps and steal unattended food.<p>Breeding occurs from August to December, typically in large colonies on offshore islands. The nest is located on the ground and consists of seaweed, roots, and plant stems. The nests may be found in low shrubs, rocks and jetties. Typical clutch size is one to three eggs. Often two broods are raised in a year, and both adults share nest-building, incubation and feeding.

Conservación

Tendencia poblacional

rising