This breeding plumage White-rumped Sandpiper was in with a mixed flock of about 150 birds (Semipalmated Plovers, Semipalmated Sandpipers, Dunlin, Ruddy Turnstones, Black-bellied Plover, Sanderling) on the bay side of Duxbury Beach about 150 yards south of the Powder Point Bridge. This photo was taken in thick fog but under a light sky