This focal geography covers the area from the Natal, at the northeastern tip of Brazil south to Tierra de Fuego (Argentina, Chile) at the extreme southern tip of South America. From Natal south the coastline is a mix of low cliffs, sandy beaches, some barrier beaches, bays and estuaries, and mangrove forests. Further south, the coastline of Rio Grande do Sul (Brazil) forms one of the longest uninterrupted beaches in the world, with a number of major lagoons behind the coast that continue into Uruguay. Coastal lagoons provide important wintering and staging habitat for shorebirds. Inland, the Pampas grasslands of southern Brazil, Uruguay, southern Paraguay and north-central Argentina are an important wintering area for grassland-dependent shorebirds.
The coastline from the Rio de la Plata Estuary to Tierra de Fuego includes a wide variety of habitats, with deltas and estuaries, sandy coasts with dunes, cliffs, pebble beaches, and rocky platforms. Important areas for shorebirds include the extensive marshes and mudflats of the Bahía Samborombón, the intertidal flats and salt marshes of Bahía Blanca, the embayment at San Antonio Oeste and the Río Gallegos Estuary. Tierra del Fuego holds vast intertidal mudflats at Bahía San Sebastián (Argentina) and Bahía Lomas (Chile). The mudflats of Tierra del Fuego and southern Argentina provide critical wintering and staging habitat for Red Knots, in addition to Hudsonian Godwits, and White-rumped Sandpipers. The coastal lagoons, wetlands and associated grasslands of southern Brazil to northern Argentina provide important wintering habitat for American Golden-Plovers and both species of Yellowlegs, in addition to Buff-breasted and Pectoral Sandpipers, while the beaches of Rio Grande do Sul state hold the most significant population of Sanderlings wintering in Eastern South America. This focal geography also supports important populations of beachnesting shorebirds, including resident populations and American Oystercatcher, and South American endemic species such as Magellanic and Blackish Oystercatchers, Two-banded Plovers, Rufous-chested Dotterels, and Magellanic Plovers.
Threats to shorebirds in Eastern South America include commercial, industrial, and residential development; incompatible coastal engineering; human disturbance; pollution; predation of eggs, chicks and adults from elevated numbers of native, non-native, and domestic predators; and, incompatible management practices.