Western Gull

The Western Gull is a big, powerfully built gull found almost exclusively along the immediate Pacific coastline, rarely straying far from saltwater. Adults have a notably dark slate-gray mantle, among the darkest of any large white-headed gull in North America, contrasting sharply with a clean white head and underparts.

The bill is thick and yellow with a bold red spot near the tip of the lower mandible, and the legs are bubblegum pink. The eye is dark, adding to the bird's somewhat fierce expression. Immature birds are mottled brown and take about four years to reach full adult plumage.

Western Gulls are a dominant, conspicuous presence at fishing harbors, piers, and seabird colonies, where they are notorious predators of the eggs and chicks of other nesting seabirds.

Key field marks

• Dark slate-gray mantle, among the darkest of West Coast large gulls
• Thick yellow bill with a bold red gonydeal spot
• Bright pink legs
• Dark eye
• Bulky, heavy-bodied build

Similar species

• Glaucous-winged Gull: paler gray mantle with wingtips only slightly darker (not black); the two species frequently hybridize where ranges overlap, producing intermediate birds.
• California Gull: notably paler mantle and yellow-green legs rather than pink.
• Herring Gull: paler gray mantle, rarely found on the immediate Pacific coast.

Habitat

Strictly coastal, favoring rocky shorelines, offshore islands, cliffs, sandy beaches, harbors, and piers; almost never found far from the ocean.

Range and migration

Breeds along the Pacific coast from Washington State south to Baja California, Mexico, with the population largely resident, though some post-breeding dispersal occurs along the coast.

Behavior

Bold and dominant, Western Gulls are frequent scavengers at harbors, fish markets, and landfills, and aggressively defend nesting territories on offshore islands, often preying on the eggs and chicks of other seabirds such as murres and cormorants.

Voice

Calls include deep, resonant "kyow" and "ha-ha-ha" notes, similar in structure to other large gulls but typically deeper and huskier.

Feeding

An opportunistic predator and scavenger, taking fish, crabs, mussels, seabird eggs and chicks, carrion, and human refuse.

Nesting and breeding

Nests colonially on offshore rocks and islands, building a ground scrape lined with grass and debris. Clutches typically contain two to three eggs, incubated by both parents for about a month.