structural:expansion, information:classification, linguistic:voice_change
Biogeography

The biogeographical areas of Asunción are two, the bay area, and the interior area. The interior area used to be covered with lush forests that made up part of the Humid Chaco, these easily exceeded 40 meters (130 ft) in height. Among the common floral species found are the tree fern or chachi, the pink lapacho (Tabebuia heptaphylla), the yvyra pytä (Peltophorum dubium), the guatambú or yvyra ñeti (Balfourodendron riedelianum), the cedar or ygary (Cedrela fissilis), etc.

Among the large animals that lived in the area that is currently Asunción were the jaguar (Panthera onca), the tapir (Tapirus terrestris), the harpy eagle (Harpia harpyja), the capuchin monkey (Cebus apella), etc. The last remnants of this great ecosystem can be seen in the Botanical Garden and Zoo of Asunción and in the surroundings of Cerro Lambare; in these places can still be find medium and small animals, such as the toco toucan (Ramphastos toco), the gold tegu (Tupinambis teguixin), the opossum (Didelphis albiventris), the Paraguayan magpie (Cyanocorax chrysops), the masakaragua'i or cucucucha (Troglodytes aedon), etc.; while some small birds such as the cardinal (Paroaria coronata), the turtle dove (Zenaida meloda), the chingolo or cachilito (Zonotrichia capensis), the golden goldfinch (Sicalis flaveola), the saijovy or common celestine (Thraupis sayaca), etc. coexist in the densely populated areas of the city with the domestic pigeon, which is an invasive specie that is reproducing at an accelerated rate, causing damage to the facades of buildings and in some cases displacing the local birdlife.

On the other hand, the bay area has an approximate area of 375 hectares (930 acres) and is located just 2 km (1.2 mi) from the old town. It is one of the most important stopping places during the journey of Nearctic and Southern migratory birds. Asunción Bay has a wide variety of habitats, yet their availability changes throughout the year giving as a result large seasonal fluctuations in the water level of the Paraguay River, which make the depth and extent of bay flooding vary considerably. During the southern winter, when the water is abundantly high, the bay is largely underwater, but towards the end of the season when the water level drops, sandy and clay beaches (tidal marsh) appear. If the waters continue to recede, most of the marshes dry out and become grasslands, some of which remain wet. A total of 258 bird species have been recorded, including 7 globally endangered species and 28 species that nest in North America and migrate to southern South America. More than 3% of the global population of one of them, the cinnamon sandpiper (Tryngites subruficollis), passes through the bay during its migration to the south, turning Asunción Bay into an Important Bird Area (IBA).