Both the western and the now extinct eastern (Phylloscopus canariensis exsul) subspecies of the Canary Islands Chiffchaff were formerly considered subspecies of the Common Chiffchaff but were separated (Clement & Helbig, 1998; Sangster et al., 2001) due to their morphological, bioacoustical, and mtDNA sequence differences (Helbig et al., 1996).