Muir's Hairstreak (Callophrys muiri)
or Juniper (Muir's) Hairstreak (Callophrys gryneus muiri)

Mt. Diablo State Park, Contra Costa Co., CA
23 May 1999 (using backlight filter on Camcorder)

Mt. Diablo State Park, Contra Costa Co., CA
23 May 1999 (without backlight filter)

Mt Diablo State Park, Contra Costa Co., CA
23 May 1999