Can someone help me ID this diving duck? I can't seem to find it in Sibley's or online. Thanks.As others have said, it's a horned grebe. It isn't a duck at all.
To clarify, Horned grebe and Slavonian grebe are two names for the same bird.
5DIII, 1DX, 8-15/4L, 16-35 f4L IS, 24-70/2.8L II, 70-200/2.8L IS II, 70-300/4-5.6L IS, 200-400/4L IS 1.4x, Zeiss 15/2.8, 17/4L TS-E, Zeiss 21/2.8, 24/3.5L TS-E II, Zeiss 35/1.4, Zeiss Otus 55/1.4, Zeiss Otus 85/1.4, 100/2.8L IS Macro, Zeiss 135/2, 600/4L IS II