This gull a regular on Silver Lake for the pat week or so appears superficially to look like a juv GBBG. Note however the two toned bill, extensive light color almost a light orangish color, similar to the legs, the head seems too small too sloped for GBBG. Bill certainly looks large enough though. Size relative to near by HERG's bulkier, larger to near same size. Long legged appearance. To me open wing looks wrong for GBBG, seems like too much contrast for GBB closer to HERG. The inner panels of the primaries seem way too light with little to no bleeding of dark color from outer across shaft of inner feathers, especially closer to tip. Tail seems ok for GBBG. I have considered HERG influences but doesn't seem to fit but most likely considering open wing. Also considered any Glaucous influences, just can't see any. So I conclude either aberrant GBBG or unidentifiable hybrid, with leaning toward HERGXGBBG.