Glaucous-winged Gull (Larus glaucescens)
Although a dozen species of gulls occur in and around Puget Sound, the Glaucous-winged is the only one that breeds in the Sound and is usually by far the most commonly seen species. It occurs in a bewildering variety of plumages, as sexual maturity is not reached until the age of four or five, and the birds change plumage every year, molting almost continuously. Light brown juveniles grow in more gray and white plumage with every molt, and the bill changes from black to yellow with a red spot, the feet from dull to bright pink.
Before the advent of human settlements in the Pacific Northwest, the Glaucous-winged Gull was primarily a fish-eater. Many individual birds still fish for a living, flying over the water and dropping down to it when they see fish at the surface. They plunk into the water from flight or while floating, submerging most of the body, and they come up with a fish (or not). Many gulls follow fishing boats to benefit from bycatch or entrails thrown overboard. Others gather at fish-processing plants for the discards.
All large gulls feed on carrion, gathering at everything from beached squids to beached whales. During low tides, glaucous-wings can be seen striding down the exposed beach looking for edibles. This includes small sea stars, urchins, chitons, limpets, crustaceans of all kinds, and fish trapped in tide pools. Gulls have long been known for their ability to open hard-shelled invertebrates such as clams by dropping them on rocks from some height, and this behavior is easily observed.
Gulls nest in colonies, and this species typically does so on islands scattered all around Puget Sound. Lacking an island, a pair of gulls may make do with the top of a cluster of pilings at a dock or the roof of an abandoned building near the water. But most of them are in large colonies of hundreds of individuals, with the territory of each pair around 10 square meters.
Nests are made of grass and other vegetation and flotsam picked up on the nesting territory and pulled loosely together. Three eggs are laid and incubated for about four weeks. The young grow quickly and leave the nest a few days after the eggs hatch but stay on the nesting territory. The adults feed them there, responding to begging and to pecks on the red spot on their bill. After a few weeks, young birds wander off territory and may congregate in little groups. They recognize the calls of their own parents and run toward them when the parents arrive with food, calling as they come.
The young can fly when six weeks old and generally leave the colony when about two months old, but for some time afterward they will beg from any adult they come near, usually with no success.