Ruff

Appearance

The Ruff has a distinctive gravy boat appearance, with a small head, medium-length bill, longish neck and pot-bellied body. It has long legs that are variable in colour but usually yellow or orange. In flight, it has a deeper, slower wing stroke than other waders of a similar size, and displays a thin, indistinct white bar on the wing, and white ovals on the sides of the tail.

This species shows sexual dimorphism. Although a small percentage of males resemble females, the typical male is much larger than the female and has an elaborate breeding plumage. He is 29–32 cm long with a 54–60 cm wingspan, and weighs about 180 g. 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 grey-brown back has a scale-like pattern, often with black or chestnut feathers, and the underparts are white with extensive black on the breast. The extreme variability of the main breeding plumage is thought to have developed to aid individual recognition in a species that has communal breeding displays, but is usually mute.

Outside the breeding season, the typical male's head and neck decorations and the bare facial skin are lost and the legs and bill become duller. The upperparts are grey-brown, and the underparts are white with grey mottling on the breast and flanks.

The female, or "reeve", is 22–26 cm long with a 46–49 cm wingspan, and weighs about 110 g. In breeding plumage, she has grey-brown upperparts with white-fringed, dark-centred feathers. The breast and flanks are variably blotched with black. In winter, her plumage is similar to that of the male, but the sexes are distinguishable on size. The plumage of the juvenile Ruff resembles the non-breeding adult, but has upperparts with a neat, scale-like pattern with dark feather centres, and a strong buff tinge to the underparts.

Distribution

The Ruff is a migratory species, breeding in wetlands in colder regions of northern Eurasia, and spends the northern winter in the tropics, mainly in Africa. Some Siberian breeders undertake an annual round trip of up to 30,000 km to the West African wintering grounds.

Status

The Ruff has a large range, estimated at 1–10 million square kilometres and a population of at least 2,000,000 birds. The European population of 200,000–510,000 pairs, occupying more than half of the total breeding range, seems to have declined by up to 30% over ten years, but this may reflect geographical changes in breeding populations. Numbers in Asia do not appear to be declining, and more Ruffs are wintering in Africa. The species as a whole is therefore not believed to approach the thresholds for the population decline criterion of the IUCN Red List. For these reasons, the Ruff is classified as "least concern".

Habitat

When not breeding, the birds use a wider range of shallow wetlands, such as irrigated fields, lake margins, and mining subsidence and other floodlands. Dry grassland, tidal mudflats and the seashore are less frequently used. The density can reach 129 individuals per square kilometre, but is usually much lower.

Food

The Ruff normally feeds using a steady walk and pecking action, selecting food items by sight, but it will also wade deeply and submerge its head. On saline lakes in East Africa it often swims like a phalarope, picking items off the surface. It will feed at night as well as during the day. When feeding, the Ruff frequently raises its back feathers, producing a loose pointed peak on the back; this habit is shared only by the Black-tailed Godwit.

During the breeding season, the Ruff’s diet consists almost exclusively of the adults and larva of terrestrial and aquatic insects such as beetles and flies. On migration and during the winter, the Ruff eats insects, crustaceans, spiders, molluscs, worms, frogs, small fish, and also the seeds of rice and other cereals, sedges, grasses and aquatic plants. Migrating birds in Italy varied their diet according to what was available at each stopover site. Green aquatic plant material, spilt rice and maize, flies and beetles were found, along with varying amounts of grit. On the main wintering grounds in West Africa, rice is a favoured food during the later part of the season as the ricefields dry out.

Just before migration, the Ruff increases its body mass at a rate of about 1% a day, much slower than the Bar-tailed Godwits breeding in Alaska, which fatten at four times that rate. This is thought to be because the godwit cannot use refuelling areas to feed on its trans-Pacific flight, whereas the Ruff is able to make regular stops and take in food during overland migration. For the same reason, the Ruff does not physiologically shrink its digestive organs to reduce bodyweight before migrating, unlike the godwit.

Predators

Predators of waders breeding in wet grasslands include birds such as large gulls, Common Raven, Carrion and Hooded Crows, and Great and Arctic Skuas; foxes occasionally take waders, and the impact of feral cats and stoats is unknown.

Defense

The nest is a shallow ground scrape lined with grass leaves and stems, and concealed in marsh plants or tall grass up to 400 m from the lek. Nesting is solitary, although several females may lay in the general vicinity of a lek. The eggs are slightly glossy, green or olive, and marked with dark blotches; they are laid from mid-March to early June depending on latitude.

The typical clutch is four eggs, each egg measuring 44 x 31 mm in size and weighing 21.0 g of which 5% is shell. Incubation is by the female alone, and the time to hatching is 20–23 days, with a further 25–28 days to fledging. The precocial chicks have buff and chestnut down, streaked and barred with black, and frosted with white; they feed themselves on a variety of small invertebrates, but are brooded by the female. One brood is raised each year.