The Glaucous-winged Gull is a resident seabird along the coast of the northeast Pacific Ocean. It breeds in colonies and occasionally as individual pairs mostly on offshore islands from northwest Washington to the Bering Sea. Winter finds the Glaucous-winged Gull occupying its breeding range and straggling as far as south Baja California and to Japan. In spring, tens of thousands of Glaucous-winged Gulls gather to feast on adult herring and their eggs, and during summer they prey on juvenile herring, among other things.

Life on a gull colony is a loud and raucous time. Each gull returns to the same nesting territory occupied the previous year to build a nest and raise their young. Territories provide only a few square meters of elbowroom and the hubbub involved in securing it shows the seriousness of its defence. Volleys of shrieking calls, bluff charges and the occasional scuffle break out as mates vie for their turf. An invisible territory line is vigorously defended against neighbouring trespassers for much of the summer. Nests are built in the territory from grasses and mosses, occasional flotsam, feathers, and other items that can be shaped into the nest.  The typical clutch of three eggs is laid in June and incubated for 27 days. Most eggs hatch in July and the precocious young gulls are entirely dependent on their parents to bring food to the territory. At this time of year, the colony is alive with begging calls of the young chicks and territorial calls of the adults. Adult gulls roam far in search of food that includes mostly refuse, fish, and marine invertebrates. The chicks are fed mostly a diet of juvenile herring but also blennies, salmon, and sculpins. The winds that sweep over the gull colonies provide a lift to adults who call to their chicks below trying to get airborne. Young gulls eventually are capable of flight by mid July and soon drift away from their natal colonies. They return as breeding age adults when they are between 3 and 5 years of age.

The Strait of Georgia in southern British Columbia holds some of the larger colonies of Glaucous-winged Gulls in the world. About 11,000 to 14,000 gulls nested when the last complete census was completed in the 1980s. 

The population trend for the Glaucous-winged Gull was upward for most of the last century. Eagle disturbances are now thought to have curtailed or reversed that trend.

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