California Gull

California Gull is among our more common winter gulls. We occasionally see thousands at a time in flocks at such places as the mouth of the Russian River. Birds usually start arriving in the county in uimbers at the beginning of August (sometimes earlier). Numbers begin to thin the following April. Most have left for breeding grounds in southeastern Oregon, southern Idaho, central Montana, Alberta and Saskatchewan by the end of May. A few birds stay over the summer at places such as Bodega Bay, but generally scarce in the county in May, June and early July. According to The Birder's Handbook and other sources, this is the species that saved the Mormons from the 1848 great plague of grasshoppers, in Utah. The "seagull" is Utah's State Bird, but it's usually understood to be this species. Full adult plumage is attained in the fourth year.

Adults in the winter plumage we usually see are identified by: A streaky or splotched brown head (with the coloration often heaviest at the back of the base of the neck); dark eyes (California Gull has dark brown eyes at all ages); smudged line through and behind the eye; comparatively, delicate bill--usually a pale, washed out yellow with black and orange-red near the tip (the dark spot may extend to the upper mandible); medium grey mantle; projecting black primaries with white spots; grey-green or pale yellowish-green legs; tail white. Dunne notes that the subadult California Gulls show a unique blue-grey-green on the legs and at the base of the bill.

A medium-sized, long-winged, elegantly shaped gull. In flight (photos below), distinct black wedges at the wingtips visible both from above and below, often with more white spotting in the primaries than Ring-billed Gull (Larus delawarensis), always with less than Mew Gull (Larus canus). Largest white spots typically in the last two primaries (biggest on last primary), particularly when seen from below. From underneath, also note the pale trailing edge of the wing and the darker area just before the pale margin. Notice that it parallels the pale trailing edge and then flares toward the black wingtip to form a much-elongated triangle of grey (bottom photo).

Juveniles (at left) are a contrasty mottled brown but often with paler neck and face and paler at the breast. Bill mostly dark brown-black, but pink at base by first winter, still dark at tip. Long, very dark brown primaries not marked with white. Tail all dark through first winter and birds retain some dark in tall through third year.

In full breeding plumage (usually seen in Sonoma county only briefly--generally from early April until departure), California Gull will have an unmarked white head, a red-orange orbital ring, red-orange at the gape, and a more fully pigmented bill than when in winter plumage. The photos below show local birds in breeding plumage in late March. From around early February, however, we start seeing birds in transition, when it's fairly common to see California gulls with a developed orbital ring, with color at the gape, and with deepening bill color, but still showing extensive streaking on the head and neck. Recently noted nesting in the South Bay Area, according to Parmeter and Wight, where it has not nested before--which may mean we will see birds in breeding plumage more often in the future.

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