Note dark eye and yellow bill with a prominent gonys-spot developing, dark markings and ivory tip giving a four-coloured appearance.
Note yellow legs.
Note the relative short, heavy and stubby bill. Nostrils are triangular being broad in front and narrow at rear.
The head is faintly dark stribed in winter with coarser spots on hindneck.
Note that underside of secondaries appear as a darker grey rectangle against the white underwing coverts and the broad white trailing edge to the secondaries.
Note that trailing edge is very broad on secondaries and narrow on inner primaries.
In flight the species appears rather stocky and flat bellied. Note the primary moult with p8 almost fully grown, p9 almost half grown and p10 not even visible.
Note relatively dark grey upperparts with extensive black and clear-cut wing tip.