The Ruff (Calidris pugnax) is the wader with the most spectacular breeding plumage in Sweden — males grow an extravagant, erectile feather ruff around the neck in almost endless individual combinations of white, black, rust-brown, yellow and brown, so that hardly two males look alike, along with tufts of feathers at the ears. Males are also dramatically larger than females, with body length ranging from 20 to 32 cm, a wingspan of 46–58 cm and a weight of 70–230 g depending on sex — one of the most extreme size differences between sexes of any Swedish bird. The female, sometimes called a "reeve", is much smaller and plainly grey-brown and mottled. Outside the breeding season both sexes are discreetly marked, recognised by a somewhat small head, short bill and orange-yellowish legs. Despite its flamboyant looks, the Ruff is a notably silent wader, rarely heard either at its display grounds or on migration.
Its breeding system is highly unusual: males gather at communal display grounds known as leks, where they perform ritualised dances and skirmishes in their finery to attract females, while taking no part in raising the young — the female alone incubates the usual clutch of 4 eggs, hidden in a tussock, and rears the chicks unaided. In Sweden the Ruff now breeds mainly on open mires in the north, since its once-common breeding on southern coastal meadows has nearly ceased; the population is declining, classed as Near Threatened, and the losses are linked to disappearing coastal meadows, mire drainage and worsening conditions on the wintering grounds. As a long-distance migrant it arrives in May and heads south towards Africa from July, and it is during migration that most birdwatchers encounter it, in large resting flocks on mudflats and coastal meadows across the country, feeding on insects, larvae and seeds while building fat reserves on nutrient-rich mud.
Read about this species in Swedish →