> Cytochrome b gene divergence between the Madeira firecrest and the European bird is 8.5%, comparable with the divergence level between other recognised Regulus species, such as the 9% between the goldcrest and the golden-crowned kinglet.[3] The split was accepted by the Association of European Rarities Committees (AERC) in 2003.[4]
The golden-crowned kinglet is similar in appearance to the common firecrest and has been considered to be its New World equivalent, but it is actually closer to the goldcrest.[3]