This large EBA at the southernmost tip of South America embraces the southern half of Santa Cruz province (Argentina), Isla Grande de Tierra del Fuego (split between Chile and Argentina), Isla de los Estados (Argentina), mainland Chile in Magallanes province just west of the Straits of Magellan, and the islands south of the Beagle Channel (Chile); it also incorporates the Falkland Islands (which are a UK dependent territory). The boundaries of the EBA coincide with the distribution of the Patagonian grasslands (and include the southern portion of Patagonian steppe). The EBA does not include the subpolar Nothofagus woodlands to the south and west of this area. Apart from the obvious coastal habitats (rocky shores and sandy beaches), the characteristic vegetation of the EBA is sparse steppe-like vegetation, tussock grasslands (Poa spp.), open scrub and tundra.

Although the EBA is a large region, the actual area occupied by the restricted-range species is substantially smaller as most are coastal and lowland birds, although some records come from as high as 1,200 m.

Ten species are entirely restricted to this EBA, at least during the breeding season (see below). As there are some widely differing habitat requirements among the nine species, a number of distributional patterns arise: Podiceps gallardoi is restricted during the breeding season to the lakes of interior Santa Cruz province (up to 1,200 m), wintering on the Atlantic coast of Santa Cruz in (at least) the Coyle estuary (Cotinga 1995, 3: 9). Similarly, Pluvianellus socialis breeds around the shores of ponds and lakes in the southern part of this province, but also in eastern Tierra del Fuego and along the southern side of the Straits of Magellan (Woods 1988); this wader has been recorded as a vagrant on the Falklands, for, although part of the population is resident, some birds move northwards up the coast of Argentina in winter (Clark 1986, Woods 1988). These and Melanodera melanodera are the only restricted-range species to be found regularly in the interior of mainland Argentina, the remaining birds being primarily coastal, although Neoxolmis rufiventris migrates north to the interior during the winter months, and Geositta antarctica has also been recorded as a migrant in central and northern Argentina. Tachyeres brachypterus is endemic to the Falklands, where it is most numerous around large kelp beds in harbours and creeks, and the recently split Troglodytes cobbi (also a Falklands endemic) appears to be restricted to tiny offshore islands where it inhabits areas with mature tussock grass (Woods 1993). Cinclodes antarcticus and Melanodera melanodera are represented on the Falklands by endemic subspecies (Woods 1988).

Among the EBA's endemics there is a great reliance, direct or indirect, on natural grasland, especially tussock grass, much of which has now been destroyed by grazing livestock and introduced herbivores (Woods 1988, Dinerstein et al. 1995). Troglodytes cobbi has a minute range, its distribution being inversely related to the presence of introduced predators whose impact may have increased with the long-term destruction of the bird's grassland habitat (Woods 1993). A number of other restricted-range species are of conservation concern, with three birds especially standing out in this respect: Podiceps gallardoi due to its small breeding range and relatively small population (fewer than 5,000); Chloephaga rubidiceps, which has declined dramatically on the mainland and Tierra del Fuego, and presently finds its stronghold on the Falklands; and Phalcoboenus australis, which has been subject to hunting throughout its range and is much reduced in numbers (Woods 1988), with a Falkland Islands population estimated at 337 breeding pairs and an immature population probably capable of no more than replacing losses in the breeding population (Strange 1996).

The widespread threatened Austral Rail Rallus antarcticus (classified as Critical) and Austral Canastero Asthenes anthoides (Vulnerable) also occur in this EBA. It has been suggested that the Falklands are the most important known breeding site for Black-browed Albatross Diomedea melanophrys, Gentoo Penguin Pygoscelis papua, Rockhopper Penguin Eudyptes chrysocome and Thin-billed Prion Pachyptila belcheri, and support important populations of a number of other seabirds (Croxall . 1984).

Protected areas in the EBA are relatively few, but include Tierra del Fuego National Park in Argentina and Magallanes National Reserve in Chile (IUCN 1992a). A number of predator-free islands supporting populations of Troglodytes cobbi are currently managed as protected areas (Warrah 1995, 7: 8-9).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Southern Patagonia. Downloaded from https://datazone.birdlife.org/eba/factsheet/63 on 22/11/2024.