The lesser scaup has a more angular head and a smaller bill 'tip' than the otherwise extremely similar greater scaup.   Both species are common in winter in the continental US, but breed in the north.   Males (like these) have black, white, and gray plumage; females (below, left and in flight) are brown with a characteristic white face marking.   These birds were photographed at the Salton Sean, in Palo Alto, at Bolsa Chica wetlands, and in San Diego (all in California)..

• Canon 1D Mk. II, 1D3, 7D, or 7D2, 500 mm f4 IS lens +2X converter or 800 mm IS lens +1.4X converter, fill-in flash for swimming birds (2004, 2005, 2007, 2009, 2017)