Cape Verde warbler

This is a medium-sized warbler, larger than the Eurasian reed warbler. It resembles that bird in appearance, grey-brown above, greyish-white below, with no obvious markings. The geographical isolation of the bird on the Cape Verde Islands prevents confusion with other similar species. The song is a distinctive liquid bubbling, like that of a bulbul.[6]

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.[7] In 2004 a further population was discovered on Fogo island[8] and further survey found it was widespread across the north of the island up to altitudes of about 1,300 m.[5] On Santiago it can be found across the whole island, including in Barragem de Poilão, S. Jorge, Serra Malagueta, Rui Vaz and Tarrafal.[5][9] 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.[1]

The population trend of the Cape Verde warbler is thought to be declining, probably because of habitat destruction and the droughts that have beset the islands.[10] With its restricted range and relatively small population, this bird has been assessed by the International Union for Conservation of Nature as a vulnerable species.[1]