Bahía de Asunción

Bahía de Asunción is a relatively small bay located along the northern outskirts of Asunción, the capital of Paraguay (in the Capital District). The bay is separated from the large Paraguay River by the Banco San Miguel, a narrow peninsula of low-lying land, and lies on the border of two geographical and ecological distinct regions of Paraguay: the lowland Chaco (western part) and the Atlantic Forest (eastern part, and Asuncion city). The bay’s water level is regulated by the Paraguay River pulses, flooding the area in autumn /winter, and receding its water level during spring/ summer.

This 522-hectare Ecological Reserve and Important Bird Area hosts more than 1% of the population of Buff-breasted Sandpiper, a shorebird species of high conservation priority. The bay’s combination of freshwater lagoons, mudflats, sandy beaches, reed beds, and seasonally inundated grasslands provides a diversity of habitats benefiting a wide range of migratory birds.

Bahía de Asunción was declared a reserve by law N° 2715 in 2005, titled “Ecological Reserve of Banco San Miguel and Bahía de Asunción.” In addition, the reserve corresponds to the Category IV of the IUCN guidelines. The Reserve is a first case of co-management between the Municipality of Asunción and the Environmental Secretariat (SEAM) – the municipality owns Banco San Miguel peninsula, and the secretariat owns the water body. Currently, they and Guyra Paraguay (national BirdLife Partner) are developing a management plan for the area.

Despite the relative small size of the area (500 hectares), a total of 269 species of birds have been recorded to date, including no less than 25 species of shorebird. Five species are of conservation concern to some extent, including four species considered near-threatened and one species considered vulnerable. Of the Nearctic shorebirds recorded here (n=19), the area is of major importance to the near-threatened Buff-breasted Sandpiper (Calidris subruficollis). Regular monitoring of shorebirds by Guyra Paraguay since 2000 showed that over 3% of its global population uses the area during southward migration. Based on the abundant presence of this species, the area was also declared an Important Bird Area under categori A4i. Other species of Nearctic shorebirds that are common in the area during migration are the American Golden- Plover (Pluvialis dominica), Lesser Yellowlegs (Tringa flavipes), White-rumped Sandpiper (Calidris fuscicollis), and Pectoral Sandpiper (Calidris melanotos).

Birds that use Bahía de Asunción as a breeding, stopover, or wintering site share it with local people who also depend on its resources. The east and south coast of Bahía de Asunción is densely populated, with the majority of the people being extremely poor. The Banco San Miguel is inhabited by fewer people, but the community is expanding as people from the interior encroach and illegally occupy pieces of land. The area is used by the local community for fishing and hunting. To a lesser extent, recreational activities are carried out.

Situated just 1 mile from downtown Asunción, the bay is exposed to many potential and current threats, including urban expansion, pollution, over-exploitation of natural resources, habitat destruction, and feral cats and dogs. The area is easily accessible and there is no control on activities carried out within the area.