Western Gull

Identification

The western gull is a large gull measuring 55 to 68 cm in length with a wingspan of 130 to 144 cm. Adults are unmistakable with a white head and body contrasted by dark grey upperparts. The head remains predominantly white year-round in most populations, with little to no streaking during the nonbreeding season. A distinctive large, bulbous-tipped yellow bill bears a red subterminal spot that chicks peck to stimulate feeding. Eye colour varies geographically, averaging pale yellow in southern birds and darker in northern populations. Western gulls require approximately four years to reach full adult plumage. Two subspecies are recognized: the northern L. o. occidentalis with dark grey mantle and darker eyes, found from Central Washington to Central California, and the southern L. o. wymani with a darker mantle approaching that of the Great Black-backed Gull and paler eyes on average, found in central and southern California.

Range & Habitat

The western gull inhabits the west coast of North America from British Columbia, Canada, to Baja California, Mexico. It is a year-round resident in California, Oregon, Baja California, and southern Washington, with migratory movements to northern Washington, British Columbia, and Baja California Sur during the nonbreeding season. This is an almost exclusively marine gull, rarely venturing more than 100 miles inland. It nests on offshore islands and rocks along the coast, and on islands within estuaries, with major colonies found on the Farallon Islands (approximately 26 miles west of San Francisco), Anacapa Island, Santa Barbara Island, Año Nuevo Island, and Alcatraz Island in San Francisco Bay.

Behaviour & Diet

Western gulls are highly territorial birds, with long-term pairs aggressively defending their nesting territories throughout the breeding season and often for the life of the male. They feed in both pelagic and intertidal environments. At sea, they take fish and invertebrates including krill, squid, and jellyfish, feeding exclusively from the water's surface as they are unable to dive. On land, they consume seal and sea lion carcasses, cockles, starfish, limpets, and snails, as well as human food refuse in altered habitats. Western gulls are notably predatory, killing and eating young of other birds, especially ducklings, and even smaller bird species and pigeons. They are known to snatch fish from cormorants' and pelicans' mouths and have been observed stealing milk directly from elephant seal teats. Their call is bright, piercing, and repetitive.

Best Time & Places to See It

Western gulls are present year-round throughout their range, making them accessible to visitors in any season. Coastal areas of California and Oregon offer the best viewing opportunities, particularly around major colonies. The Farallon Islands, accessible by boat from San Francisco, support the largest colony with an estimated 30,000 gulls in the San Francisco Bay area. Channel Islands National Park, featuring Anacapa and Santa Barbara Islands, provides excellent viewing and photography opportunities. Rocky coastlines, estuaries, marinas, and beaches throughout the Pacific coast from Washington to Baja California are reliable locations to observe this species in its natural marine habitat.

Photography Tips

The contrast between the white head and dark grey mantle makes western gulls visually striking subjects, especially in strong coastal light. Photograph adults during breeding season when territorial behaviour is most active and visible. For capturing characteristic plumage details, focus on the distinctive yellow bill with its red subterminal spot, which is particularly visible when birds are calling. The four-year maturation process means younger birds will lack the full adult plumage; plan visits to established colonies where multiple age classes can be photographed together. Early morning light on rocky islands and coastal outcrops enhances the dramatic contrast of their plumage. Watch for feeding behaviour in intertidal zones at low tide or around fishing operations where their predatory and kleptoparasitic behaviours provide dynamic photo opportunities.