At one time it was thought that the Cape Verde warbler was restricted to the island of Santiago. After a specimen was found in a Lisbon museum, a survey was made on São Nicolau island in 1998 and some individuals were found there. In 2004 a further population was discovered on Fogo island and further survey found it was widespread across the north of the island up to altitudes of about 1,300 m. On Santiago it can be found across the whole island, including in Barragem de Poilão, S. Jorge, Serra Malagueta, Rui Vaz and Tarrafal. Although previously thought to be mainly restricted to woodland and scrub, it is now reported from a wider range of habitats including well-vegetated valleys, reedbeds, cultivated land and around water sources such as dams.