Western Gull

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Image:WesternGull.JPG

Common Name: Western Gull
Scientific Name: Larus occidentalis

Size: 23.6 inches (60 cm)

Habitat: North America; The Western Gull ranges from British Columbia, Canada to Baja California, and Mexico. It is rarely encountered inland or away from the ocean and is almost an exclusively marine gull.

Status: Vulnerable. Global Population: 120,000 mature individuals. Despite being a well-known bird species on the West Coast of the US, it is of some slight conservation concern given its restricted range for a gull. Western Gulls are very aggressive when defending their territories and consequently were persecuted by some as a menace. The automating of the lighthouses, and the closing of Alcatraz Prison, allowed the species to reclaim parts of its range. They are currently vulnerable to climatic events like El NiƱo events and oil spills.

Diet: At sea they take fish and invertebrates like krill, squid and jellyfish. They cannot dive, and feed exclusively on the surface. On land they feed on seal and sea lion carcasses, as well as cockles, limpets and snails in the intertidal zone. It also drops shellfish on to rocks to break them. They also feed on human food refuse, in human-altered habitats, including waste landfills, and taking food from people at marinas and beaches.

Breeding: Male and female look alike. Western gulls take approximately four years to reach their full plumage. In the colonies, long term pairs aggressively defend territories whose borders may shift slightly from year to year, but are maintained for the life of the male.

It nests from late April or early May, and later in the north, nesting on barren substrates in colonies on rocky islets with some herbaceous cover and gravelly beaches.

Cool Facts: It was previously considered conspecific, the same species, with the Yellow-footed Gull (Larus livens) of the Gulf of California. In Washington state, the Western Gull hybridizes frequently with the Glaucous-winged Gull, and may closely resemble a Thayer's Gull. The hybrids have a flatter and larger head and a thicker bill with a pronounced angle on the lower part of the bill, which distinguishes it from the smaller Thayer's Gull.

The Western Gull typically lives about 15 years, but can live to at least 25 years.


Found in Songbird ReMix Seabirds Volume 2

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