Cape Verde Warbler (Acrocephalus brevipennis)

This insectivore measures up to 14 cm in length and is not easily spotted because it hides in forests and shrublands. Endemic to Cape Verde, it is found on the islands of São Nicolau, Santiago and Fogo, and perhaps on Brava, although there have been no sightings since the 1960s; it is very rare on São Nicolau and extremely localized. This species is closely related to the greater swamp-warbler (Acrocephalus rufescens) found in West Africa. Generally chestnut-coloured on the back, but paler on the belly, it has a thin bill, which is characteristic of insect-eating birds. This warbler has a loud voice and a striking call, quite distinctive from other birds of Cape Verde, and bursts into song just after the rains, from August to October. It breeds in reed beds, fruit trees, and a variety of other trees and bushes, including Prosopis juliflora. Outside of the breeding season, it forms small flocks, occasionally with blackcaps (Sylvia atricapilla), which feed off fig trees (Ficus sycomorus).