This IBA includes the adjacent islands of Siargao and Bucas Grande Islands, which lie a few kilometers off the north-eastern coast of Mindanao. They are low-lying islands that rise to a maximum altitude of only 290 m. There are very extensive mangrove forests on the island, which cover a total of c. 8,700 ha. There are large areas of old growth lowland dipterocarp forest (reported to cover c.12% of the island) and secondary or residual forest (reported to cover 33% of the island), and areas of grassland (reported to cover 12% of the island).
Several of the threatened and restricted-range species of the Mindanao and Eastern Visayas Endemic Bird Area have been recorded on the island of Siargao, mainly during a collecting expedition in 1972, including Lesser Eagle-owl, Silvery Kingfisher and Wattled Broadbill. This IBA is particularly notable for the population of the critically endangered Philippine Cockatoo that survives there.
Non-bird biodiversity: Other threatened and endemic animals recorded on Siargao include the Saltwater Crocodile Crocodylus porosus, marine turtles (Hawksbill Turtle Eretmochelys imbricata, etc.), Philippine Tarsier Tarsius syrichta, Flying Lemur Cynocephalus volans and Dugong Dugong dugon. The interesting flora includes fire orchids, century orchids Dendrobium and Pitcher plants Nepenthes spp.
BirdLife International (2020) Important Bird Areas factsheet: Siargao island. Downloaded from http://www.birdlife.org on 26/10/2020.