This bird appears to be a hybrid between Lesser Scaup and Ring-necked Duck. The back is dark with faint pale vermiculations. The head is more peaked than Lesser Scaup and the bill nail is too broad for scaup, but not broad enough for Ring-necked Duck. The head sheen is odd, somewhat greenish, perhaps suggesting Greater Scaup (Aythya marila) as one parent, but that species does not breed in this area while Lesser Scaup is a common breeder.
Digiscoped with Panasonic DMC-LZ5 | Nikon FieldScope III | 30XWA | hand-held (no adapter)