Stiff wind prevented decent photos but in 1.5 hours we were able to scope a nice bundle of birds embedded within a single flock dominated by Surf Scoters.  Present were a male Black Scoter, 2 and possibly 3 White-winged Scoters, the male Harlequin Duck, and a Red-necked Grebe.  

Our viewing position was at Jetty Point near the Port San Luis Pier; the flock of birds was at approximately 35.17242  -120.74993. I.e., they were closer to the Port San Luis Pier than to the Cal Poly Pier.