The rufous-chested plover (Charadrius modestus) or rufous-chested dotterel, is a species of bird in subfamily Charadriinae of family Charadriidae. It is found in Argentina, Brazil, Chile, Uruguay, and the Falkland Islands. Taxonomy and systematics The rufous-chested plover has been placed by itself in genus Zonibyx by several authors but that treatment has not been widely accepted. There is some 21st century evidence that it does not belong in Charadrius. The rufous-chested plover is monotypic. Description The rufous-chested plover is long and weighs . Adult males in breeding plumage have a gray face with a bright white supercilium, a gray throat, and a brown crown. Their breast is bright rufous with a black band below it; the rest of the underparts are white and the upperparts brown. Adult females are similar but duller. Non-breeding adults replace the rufous and gray with pale brown; their upperparts feathers have bright fringes and their supercilium is creamy. Juveniles resemble the non-breeding adult but have darker brown upperparts and breast. Distribution and habitat The rufous-chested plover is found on the Falkland Islands and coastally to somewhat inland in Argentina, Uruguay, extreme southeastern Brazil, and Chile. It has also been recorded as a vagrant in Paraguay and Peru. In the breeding season it primarily inhabits short grasslands away from the coast but also boggy or stony areas around inland lakes and coastal shingle. Outside the breeding season it inhabits inland eroded and flooded grasslands, marshes, and streams, and also coastal mudflats, beaches, and rocky shores. Behavior Migration The rufous-chested plover breeds in far southern Chile and Argentina and on the Falkland Islands. A few remain in those areas year-round but most migrate north as far as northern Chile and extreme southern Brazil. A few occasionally move further to Peru and Paraguay. Adults begin their migration as soon as the young are independent. Feeding The rufous-chested plover forages in grasslands and along the edge of ponds, waterways, and the sea. During the breeding season it often defends small feeding territories and outside it often forages in flocks of 30 or more. Its diet is mostly small invertebrates including adult and larval insects and molluscs, and also includes some plant material such as algae. Breeding The rufous-chested plover's egg season is mostly October and November, and includes September on the Falkland Islands. Its nest is a depression in the ground, often in the open. The clutch size is