An Imperial Beach Hidden Gem and Bird of the Week, the Western Gull
Jun 14, 2017 09:44PM
By Paul Spear
An Imperial Beach Hidden Gem and Bird of the Week, Bryan Brillhart Photography present the “Dig IB” Bird of the Week, the Western GullWestern Gull
This week’s “Bird of the Week” is the Western Gull (Larus occidentalis), the only gull nesting along most of the Pacific Coast from Washington to Baja, Mexico,
this large species is common at all seasons. An opportunist, it often nests around colonies of
other seabirds, where it can steal unguarded eggs or chicks. It will also nest near colonies of California sea lions, scavenging any sea lion pups that die of natural causes. At the northern end of its range it hybridizes with Glaucous-winged Gull, and many intermediate birds are seen. They are common, and numbers are apparently stable. Nesting at some colonies has been impacted in the past by effects of pesticides in the food chain.
Habitat is along coastal waters, estuaries, beaches, and city waterfronts, mostly along the immediate coast, but regularly found well out at sea, especially between coast and nesting islands. They visit garbage dumps, ponds, and flat open areas (such as parking lots) within a few miles of the coast, but are almost never found farther inland. Nests are on islands and locally on mainland cliffs.
Western Gulls forage while walking or swimming, or may plunge into water from flight. They may drop hard-shelled clams and crabs onto rocks while in flight to break them open. I have witnessed this behavior many times on our beaches.
Western Gull diet is fish and other marine life, eggs, carrion, and refuse. They feed on a wide variety of aquatic life, including fish, crabs, squid, clams, and sea urchins. They will eat eggs and young (and sometimes adults) of other birds. Around sea lion colonies, they scavenge dead pups and afterbirth, and they also eat other carrion, and scavenge in dumps and around docks for refuse.
After mating, females lay usually 3, sometimes 1-5, rarely 6 eggs. Clutches of more than 3 eggs result from 2 females laying in same nest, which happens fairly often at some colonies. Eggs are buff to olive or gray, blotched with darker brown. Incubation at normal nests is by both parents (female may do more), in about 25-29 days. In very hot weather, adults may fly to water and soak their belly feathers to cool their eggs. Young chicks are fed by both parents. Chicks may leave their nest when a few days old and hide in nearby vegetation. Chicks are capable of flight at about 6-7 weeks after hatching. Young depart from some colonies at about 10 weeks, becoming independent then; at other colonies, young may be fed by parents longer.
Western Gulls first breed at 4 years or older. Nests are in colonies. Nest sites are on ground or on a cliff ledge, sometimes on a boat or building, or sometimes under an overhanging rock. Nests (probably built by both sexes) are a shallow depression, usually with a lining of grass, and other plants.
Western Gulls are very easy to spot along our great beaches, and occasionally within the Tijuana Estuary. Look for them flying straight up with clam or oyster shells, and then dropping them to break them open. Until next week, happy birding!
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