The humid forests of the eastern slope of the Andes of south-east Peru, Bolivia and Argentina are known collectively as the yungas. This EBA embraces the higher-altitude yungas (largely 1,800-3,700 m) on the northern slope of the Cordillera Central (a side branch of the main Andean range) from Cuzco and Puno departments of south-east Peru to La Paz, Cochabamba and extreme western Santa Cruz departments of central Bolivia. Also included are the parallel cordilleras of Vilcabamba, Vilcanota and Carabaya in south-east Peru which branch off northwards from the main Andean chain.

The climate's great humidity comes from the northerly trade winds which deposit water droplets as well as rain. The habitat is evergreen montane forest (including cloud forest), and is often on steep slopes, trees being laden with epiphytic bromeliads, orchids, ferns and mosses, and tree-ferns and bamboo (mainly Chusquea) are conspicuous (e.g. Remsen 1985, Whitney 1994). At or near crests and ridges the forest is lower in stature and even wetter (elfin forest), and at the EBA's upper elevational limits the vegetation changes to scrub, marking the transition between forest and the páramo grassland above.

Most of the restricted-range species are typical of the montane evergreen forest. Some, however, such as the two hummingbirds (Aglaeactis pamela and Metallura aeneocauda) and the furnariids (Cranioleuca albiceps, C. marcapatae, Schizoeaca harterti and S. helleri) are found mainly in the transition between elfin forest and páramo grassland and scrub that is prevalent at the highest elevations. The species differ in their distributional patterns: four are restricted to the Vilcabamba and Vilcanota, 11 occur in the Eastern Andes from Cuzco department (Peru) through to central Bolivia, and five are found throughout (see 'Distribution patterns' table, below).

Large tracts of forest are still present in this EBA but in some parts, most notably at lower altitudes, there is land clearance for subsistence agriculture and cash crops (coca, coffee, tea), and logging which is being intensified by colonization and roadbuilding (Dinerstein et al. 1995). None of the bird species, however, is currently considered threatened.

There are several protected areas in Peru and Bolivia that hold some of this EBA's habitat. Probably the most important are, in Peru, the Tambopata-Candamo Reserved Zone (14,800 km²), which includes Manu National Park and Manu Reserved Zone (a Biosphere Reserve and World Heritage Site), and, in Bolivia, Amboró National Park (1,800 km²), which holds most of the EBA's restricted-range species, and the newly created Madidi National Park and Integrated Management Area (19,000 km ^2>), which includes land from peaks at 5,500 m down to lowland tropical rain forest and savanna (World Birdwatch 1995, 17 (4): 3), and so holds a significant tract of evergreen montane rain forest of the upper yungas (much of the park awaits survey but it is predicted to have the highest avian diversity of any protected area in the world; only three of the restricted-range birds of this EBA have been recorded so far, but a further 10 are expected to occur: Parker and Bailey 1991, Remsen and Parker 1995).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Bolivian and Peruvian upper yungas. Downloaded from https://datazone.birdlife.org/eba/factsheet/57 on 22/11/2024.