The site is located 18 km south-east of Tsinjoarivo. Its rugged terrain of high, rounded hills is furrowed by narrow valleys. The Onive river flows through the southern part of the site. The mid-altitude, dense, humid evergreen forest has a canopy 10–15 m high, dominated by trees of Deinbollia, Dombeya, Ocotea, Tambourissa, Nuxia and Weinmannia.
See Box and Tables 2 and 3 for key species. Seventy-one species are known from the site, of which 44 are endemic to Madagascar. The bird community is characteristic of mid-altitude humid forest.
Non-bird biodiversity: Lemurs: Eulemur rubriventer (VU), Varecia variegata variegata (EN), Propithecus diadema diadema (EN). Carnivores: Fossa fossana (VU), Cryptoprocta ferox (VU).
BirdLife International (2022) Important Bird Areas factsheet: Onive Classified Forest. Downloaded from http://www.birdlife.org on 07/10/2022.