 The kinglets are a small group of birds sometimes included in the Old World warblers , but frequently given family status , especially as recent research showed that , despite superficial similarities , the crests are taxonomically remote from the warblers . The names of the family , Regulidae , and its only genus , Regulus , are derived from the Latin regulus , a diminutive of rex , " a king " , and refer to the characteristic orange or yellow crests of adult kinglets . The species name madeirensis is derived from the island on which this bird is found . The Madeira firecrest was first described by English naturalist Edward Vernon Harcourt in 1851 . Until recently , it was considered to be a subspecies , R. i. madeirensis , of the common firecrest R. ignicapillus . A phylogenetic analysis based on the cytochrome b gene showed that the Madeiran form is distinct at the species level from the firecrest nominate subspecies R. i. ignicapillus . 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 . The split was accepted by the Association of European Rarities Committees ( AERC ) in 2003 , but some authorities , such as Clements , have not yet recognised the new species . The International Ornithological Congress ' recommended English name for this species was " <unk> " , but this has been changed to " Madeira firecrest " . 
