The island is a large, oblong rock, rising precipitously from the sea to a height of 327 m. A ridge runs the length of the island, dropping steeply to the coast which, with the exception of an area of dunes on the western side and a small area of level ground in the extreme east, is entirely rocky. The seas around the island are turbulent for much of the year, making landing difficult.
See Box for key species. Branco is one of the major sites for breeding seabirds in the Cape Verdes. Together with the nearby islet of Raso (site CV011), it holds the main breeding population of Calonectris (diomedea) edwardsii, and there are also significant numbers of Puffinus (assimilis) boydi and Oceanodroma castro, and a colony (c.250 pairs) of Pelagodroma marina. Other breeding taxa include Egretta garzetta, Pandion haliaetus, Falco (tinnunculus) neglectus and Tyto (alba) detorta; the rare Falco (peregrinus) madens is suspected to breed.
Non-bird biodiversity: The endemic giant skink Macroscincus coctei (males up to c.65 cm in length), which only occurred on Branco and Raso and lived alongside the breeding seabirds in clefts and holes, is considered extinct. It has not been seen since the early twentieth century and is thought to have been wiped out through over-exploitation. Its skin was used for making shoes, while ‘criminals’ marooned on Branco in the past by the colonial Portuguese authorities, and who had to fend for themselves, caught them for food, as did visiting fishermen. The endemic giant gecko Tarentola gigas is still present in good numbers.
BirdLife International (2019) Important Bird Areas factsheet: Ilhéu Branco. Downloaded from http://www.birdlife.org on 23/01/2019.