The Upper Bay of Panama includes very extensive tidal mudflats (11,000 ha) up to 3 km wide, from Costa del Este just east of Panama City to the Ensenada de Corral at the mouth of the La Maestra River 70 km to the east. Near Panama City the site borders heavily urbanized and suburban areas, while the eastern part is relatively remote and difficult of access except by boat. Rivers draining into the bay include the Bayano (by far the largest), Juan Díaz, Cabra, Pacora, Chico, Pasiga, and La Maestra. On the landward side the site is contiguous with Tocumen Marsh and La Jagua, which are national-level IBAs, and
merges with the Chimán Wetlands IBA to the east.
The Upper Bay of Panama is one of the most important areas for migratory shorebirds in the Americas. The highest single day count was more than 362,952 in October 1998 (Watts 1998). If turnover is taken into account, an estimated 1,300,000 small shorebirds pass through on autumn migration. Western Sandpiper is by far the most abundant species, with an estimated single day count of more than 280,000 (Watts 1998). With turnover, 31.5% of the global population of this species is estimated to pass through the site each year. The next commonest species is Semipalmated Sandpiper, with a maximum count of 47,000 (Watts 1998), representing 4.7% of the global population if turnover is taken into account. It is also very important for Semipalmated Plover, with a highest single day count of more than 30,000 (Watts 1998), representing 20.1% of the global population estimate of this species, even without turnover. Single day counts also exceed 1% of the global or North American populations for Black-bellied Plover (1.6% of North American), Willet (4.3% of global), Whimbrel (10.3% of North American), and Short-billed Dowitcher (1.9% of global). The largest concentrations are found in the western part of the site, near Panama City. There is a large heron nesting colony, including Cocoi Heron and Great Egret, in the mangroves at Ensenada de Corral at the eastern edge of the area. The site is an important foraging area for Peregrine Falcon.
Non-bird biodiversity: Neotropical River Otter, Crab-eating Raccoon, and American Crocodile probably occur.
Pressure/threats to key biodiversity
The western part of the area is threatened by urban development as Panama City spreads eastwards. In 1997-98, a new housing development was constructed on the coast at Costa del Este, in an area used by up to 40,000 shorebirds as a high-tide roost. It is not known how this development, including the draining of shallow marshes and the construction of a seawall, have affected use of the area by shorebirds. Part of the new Southern Corridor Highway between Panama City and Tocumen Airport was constructed on a causeway over the mudflats in the westernmost part of the area, although only a relatively small area was directly affected. Panama City does not have sewage treatment facilities, and untreated sewage and industrial waste is dumped directly into the bay. A wastewater treatment system is currently being planned. The area may also be affected by pesticides and other chemicals used in agriculture in adjacent areas. The enormous flocks of shorebirds can present an impressive spectacle, and the area has considerable tourism potential. However, heavy concentrations of plastic containers and other washed-up trash line the shore near Panama City and detract from the experience, and security can be a concern in some areas.
Conservation responses/actions for key biodiversity
The Panama Audubon Society has a number of ongoing projects in the area.
The area was declared a Wetland of International Importance under the Ramsar Convention in 2003, and part of the Western Hemisphere Shorebird Reserve Network in 2005. However, it has not yet been formally recognized as a nationally protected area.
Habitat and land use
The area includes very extensive intertidal mudflats as well as large areas of mangroves in the Río Bayano estuary and smaller areas elsewhere. Adjacent on-shore habitats include freshwater wetlands, patches of scrubby semideciduous lowland forest, and agriculture, including rice cultivation, cattle, and subsistence agriculture, and urban areas at the western end of the site.
BirdLife International (2020) Important Bird Areas factsheet: Upper Bay of Panamá. Downloaded from
http://www.birdlife.org on 21/10/2020.