Remsen, J.V. 1975 Thayer's Gull Larus thayeri Oct.31 Salinas River Valley, Monterey Co., Calif: 1 ad. Moss Landing - white underwing tips). Nov.2 Monterey area, Monterey Co., Calif: 1 imm. (1st-yr) on beach near Lover's Pt; ID by Binford. Dec.6 Fairmont Park, Riverside Co., Calif: 1+ imm on Evans Lake Dec.13 Fairmont Park: 3 1st-yr Dec.14 Palos Verdes Point, Los Angeles Co., Calif: 2 1st-yr. Coastal Orange Co., Calif: 1 1st-yr, Dec.20 San Diego area, San Diego Co., Calif.: 5 1st-yr. Dec.21 San Diego area: 25 1st-yr birds, 1 2nd-yr (like 1st-yr in every way but gray beginning to appear in mantle). The wingtip color is variable -- ranging from nearly as pale as Glaucous-winged 1st-yr to nearly as dark as Herring 1st-yr. - the extremes are problem birds since some Thayer's are nearly as large as the larger gulls - one had a bill nearly as heavy as a Herring Gull's. In flight, the wings appear very pale, especially the outer primaries, and even dark-primaryed birds appear pale, - in flight, they are toughest to tell from Glaucous-wingeds. The tail of the first-yr. birds is uniform tan-brown and the uppertail coverts were mottled. The pig-farm off Otay Rd. is a great place to study these birds at close range. Dec.25 Santa Cruz area, Santa Cruz Co., Calif: 6 first-yr. birds