A major feature of the park is the density and variety of bird species, a major factor in the creation of the reserve, due in part to its diverse ecology, with 15 different topographical zones from evergreen forests to mangrove swamps. Birds spotted regularly in the park include Great Curassows, Scarlet Macaws, white ibis, roseate spoonbills, anhingas, jabirus, and wood storks among many others. The park protects one of the most endangered ecosystems. It is one of the last remaining tropical dry rainforests that once covered most of Central America. Tropical dry rainforests now exist in less than 0.1% of their original size and are considered to be the most endangered ecosystems in the tropics.

The Palo Verde National Park, Spanish for "Green Tree", is a National Park of Costa Rica, part of the Tempisque Conservation Area, that contains much of the area of the valley of the Tempisque River and covers an area of 45,492 acres in Guanacaste Province, 30 km west of Canas. The surrounding region is mostly tropical dry forests, and the Park concentrates on conserving vital floodplain, marshes, limestone ridges, and seasonal pools from the encroachment of civilization which was putting the ecology of the area at risk.