Identification: Non-breeding adult has grey upperparts, mostly white head and neck with prominent broad black head-stripes and blackish streaks down centre of foreneck, black nape-plumes, whitish underparts, black shoulder-patch and dull yellowish bill. Breeding adult has bright orange-yellow bill, legs and feet. Juvenile resembles non-breeding adult but is duller and has less contrasting head and neck pattern and much shorter head-plumes.