In breeding plumage, she has grey-brown upperparts with white-fringed, dark-centred feathers.The breast and flanks are variably blotched with black.
In the May-to-June breeding season, the typical male's legs, bill and warty bare facial skin are orange, and he has distinctive head tufts and a neck ruff.
These ornaments vary on individual birds, being black, chestnut or white, with the colouring solid, barred or irregular.
The striped prenuptial plumages may represent the original breeding appearance of this species, the male's showy nuptial feathers evolving later under strong sexual selection pressures.
Adult males and most adult females start their pre-winter moult before returning south, but complete most feather replacement on the wintering grounds.
The ruff (Calidris pugnax) is a medium-sized wading bird that breeds in marshes and wet meadows across northern Eurasia.
This highly gregarious sandpiper is migratory and sometimes forms huge flocks in its winter grounds, which include southern and western Europe, Africa, southern Asia and Australia. This species shows marked sexual dimorphism; the male is much larger than the female (the reeve), and has a breeding plumage that includes brightly coloured head tufts, bare orange facial skin, extensive black on the breast, and the large collar of ornamental feathers that inspired this bird's English name.
This decline has seen it listed in the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA).
The ruff is a wader in the large family Scolopacidae, the typical shorebirds.
It has long legs that are variable in colour but usually yellow or orange.