Glaucous-winged Gull

Glaucous-winged Gull is present in Sonoma County mostly in the winter months, although a few birds may stay over the summer, notably at Bodega Bay. The birds usually start arriving in mid-October, but the bulk of the incoming population seems to arrive in early November. Birds usually stay through mid-March, but a few may linger into April. Generally present only sporadically between May and September. Breeds in coastal southern Alaska and coastal British Columbia, moving south during the winter months into our area and as far south as northern Baja California. Glaucous-winged Gull attains adult plumage in its fourth year.

The adults we see are large, pink-legged gulls with a medium to pale grey mantle (often with a bluish hint in non-breeding plumage) and primaries about the same color as the mantle. The white spots visible in the folded wings of standing Glaucous-winged Gulls (as in the photo above) are distinct but contrast less sharply with the primaries than do the same spots in nearly all the other gulls we commonly see in the county. All locally present adult gulls have black or near-black primaries--with the exception of the rather rare Glaucous Gull (Larus hyperboreus), which has virtually white primaries. Glaucous-winged gull has a fairly heavy yellow bill marked with a red spot on the lower mandible. The head, neck, and upper breast are smudged with grey rather than streaked as in many other winter gulls in non-breeding plumage. Note that the folded wings project only slightly beyond the end of the white tail. Eye-color seems to be quite variable in this gull. The bird photographed above has a fairly pale eye and some field guides illustrate Glaucous-winged Gull with a pale iris (Birds of Northern California, for example), but most descriptions call the eye dark. Known to frequently hybridize with Western Gull and these birds backcross with their parent species, which creates a wide range of intermediate birds that can be very confusing indeed.

Also see: A comparison of common gull heads in breeding and non-breeding plumages

Selected county sightings: Goat Rock Beach, Jenner (February 23, 2012); Roberts Park (December 12, 2011); Lucchesi Park, (November 14, 2011, Gene Hunn); Duncan's Landing (March 10, 2011); Duncan's Landing (February 26, 2011, Bill Doyle); Bodega Bay (April 1, 2010)