what is a ruff?
Medium-sized wading bird.
Ruff (bird)
The ruff ("Calidris pugnax") is a medium-sized wading bird that breeds in marshes and wet meadows across northern Eurasia. 
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Ruff (bird) [SEP] Introduction
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. The ruff is a long-necked, pot-bellied bird. 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.