Geographic and climatic barriers divide the country of Peru into discrete units, each with distinct avifauna. Elevation also has a tremendous impact on the distribution of birds and species composition.
Peru is divided into three contrasting topographical regions: the coast (Costa), the highlands (Sierra), and the eastern rainforests (selva). The coastline is a narrow ribbon of the desert plain from 16 to 160 km (10 to 100 mi) broad that constitutes only 12% of the national territory.
The costa rises inter western inter-Andean mountains and valleys (760–2,000 m/2,500–6,500 ft), then ascends abruptly to the western cordillera of the Andes, which runs parallel to the coast and forms the Peruvian continental divide.
The intermontane basins, deep-gashed canyons, and high treeless plateaus (punas) of the Andes form the Sierra and constitute 27% of the country’s surface. The most important rivers draining the Andes on the Atlantic watershed flow east to form the Amazon Basin.
The Amazon basin covers 61% of Peru and consists of the low selva (the Amazon rainforest) and the high selva, a steeply sloping transition zone about 100–160 km (60–100 mi) wide between the Sierra and the rain forest.
The map below shows a color-coded illustration of Peru’s topography. The map on the right shows a crossed-section of Peru starting from the coastal lowlands, over the Andes and down to the Amazon basin.
Topographic Cross Section of Peru
The figure below shows a cross view east to west from the western coastal lowlands up to the Andes and down to the eastern Amazon basin.
The terminology used on this map is used in the descriptions of bird distribution.