Scrolling down shows a sequence of the plumages of Western Gull, from adult breeding to downy chick. Western x Glaucous-winged hybrids are common; two probable examples if you scroll to the bottom here.
Western Gull, Larus occidentalis
Probable adult albino Western Gull here.
Western Gull, breeding plumage, 7/14/07, Salinas State Beach, Monterey Co
Western Gull, adult breeding, 3/27/04, Morro Bay, San Luis Obispo Co
Left, above, and below, breeding plumage, almost indistinguishable from adult winter plumage. Most gull species have pure white heads when breeding, streaked heads in winter; Western Gull has pure white all year round.
Western Gull, breeding, 8/1/04, Salinas State Beach, Monterey Co
Western Gull, winter adult, 2/24/07, Point Pinos, Monterey Co
Adult winter plumage, in flight below, standing above.
Western Gull, 3/28/07, Point Pinos, Monterey Co
Western Gull, thrid winter, 2/26/05, Pt. Pinos, Monterey Co
Western Gull, third winter, 1/13/04, Bodega Bay, Sonoma Co
Three pictures, above, left, and below, of third winter birds; like adult, but no white tips to the primaries, the gonys still mostly dark, usually some dark feathers in the tail, seen in all three of these, and sometimes, a few brown feathers in the upperparts.
Western Gull, third winter, 9/23/06, Pt Pinos, Pacific Grove, Monterey Co
Western Gull, second summer,  5/25/06, Salinas State Beach, Monterey Co
Western Gull, second summer, 6/26/04, Bodega Bay, Sonoma Co
Second summer birds, above and left: white rump and head; first appearance of red in the gonys; adult gray mantle and median coverts; immature brown flight feathers and lesser coverts.
Western Gull, second winter, 3/11/07, Venice Beach, Half Moon Bay, San Mateo Co
Western Gull, second winter, 11/20/04, Gualala River Mouth, Sonoma Co
Second winter, left and above, showing a mostly adult white head, and a mix of adult gray and immature brown feathering on the upperparts. The pattern on the bill varies a lot in immature birds after the first winter.
Western Gull, first summer, 5/25/06, Salinas State Beach, Monterey Co
Western Gull, first summer, 8/1/04, Salinas State Beach, Monterey Co
Left and above, first summer birds; head feathers lighter than first winter; flight feathers retained, very worn and ragged.
Western Gull, first winter, 2/2/09, Pillar Point, San Mateo Co
Western Gull, first winter,  11/13/04, Bodega Bay, Sonoma Co
First winter, November above; left and below, September and August birds still almost entirely in juvenal plumage.
Western Gull, juvenile, 9/23/06, Pt Pinos, Pacific Grove, Monterey Co
Western Gull, juvenile, 8/30/07, Salinas State Beach, Monterey Co
Western Gull, juveniles, 8/9/03, Bodega Bay, Sonoma Co
Three juveniles, fully fledged, begging in unison.
Western Gull, downy chicks, 6/26/04, Bodega Head, Bodega Bay, Sonoma Co
Two downy chicks, eyes only partly open, not long out of the egg.
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