The Vilcabamba valley floor is a patchwork of fruit orchards, cane fields and pastures. The dry western slopes contrast with the eastern slopes which are made up of pasture and thorny scrub forest including the Huilco tree (Anadenanthera colubrina) which gives the area its name. Higher up, continuing east of the village of Vilcabamba following the Yambala river valley the farmland gives way to scrub forest then to premontane forest and, at the upper reaches near the National Park boundary to cloud and elfin forest and finaly to paramo and the peaks of the central cordillera of the Andes.
Many species bird watchers will find at Cajanuma, the Loja entry to the Podocarpus National Park, are also found in the upper regions of the Vilcabamba valley. In fact the Bearded Guan, endemic to the park, apears more numerous in the upper regions of Vilcabamba, such as in the upper parts of the Yambala and San Pedro Valleys. Other noteworthy species are Red-faced Parrot, Golden-plumed Parakeet, Gray-breasted Mountain-Toucan, Scaly-naped Amazon, Stygian Owl and Rainbow Starfrontlet. The Torent Duck has been seen from the lower Yambala valley to about 2000mt. below the park. The lower, dry slopes and valley floor support many species that aren't in the Podocarpus National Park. Although several of the Tumbesian dry forest endemics have been found in the scrub forests and thickets of the valley; Chapman's Antshrike, Three-banded Warbler, Black-cowled Saltator and Bay-crowned Bush-finch.
This is the only known Ecuadorian locality for Plumbrous Rail (first seen in 1991), and is reasonably common around Vilcabamba. Best seen along trails and minor roads along the lower valley.
Further south past Yangana, before dropping to Valladolid, is Quebrada Onda where the Jocotoco Antpitter, a new species of Antpitter, was found. In the same area is the refuge of the Jocotoco foundation. One can stay at this refuge by contacting the Fundacion Jocotoco.