The Glaucous-winged Gull is a large gull of Pacific shorelines. Adult wingtips are pale gray like the rest of the upperwing, and the bird searches coastlines for fish and crabs.
A breeding adult has pearly gray wingtips, a white underside, and pink legs. A nonbreeding adult may have brownish mottling on the head and neck.
Mandarte Island in Canada holds a large breeding colony of Glaucous-winged Gulls. A comparison of breeding records found that hatching success fell from about 83% in the 1960s to 76% in the 1970s and 1980s, then to 60% in 2008–2010. The records show how reproductive outcomes at the coastal colony changed across several decades.
The share of eggs that produced fledglings also fell, from about 63% in 1962 to 52% in 2008–2010, although that change was not statistically clear. Long-running records from the same island made it possible to compare breeding across generations of gulls. The study also recorded changes over time in egg size and clutch size.
An extinction-risk assessment has not been added yet.
At Mandarte Island, Glaucous-winged Gull hatching success fell from about 83% in the 1960s to 60% in 2008–2010. The share of eggs producing fledglings fell from 63% to 52%, but that change was not statistically clear.