White Wagtail - Taxonomy and Systematics

Taxonomy and Systematics

The White Wagtail was one of the many species originally described by Linnaeus in his 18th century work, Systema Naturae, and it still bears its original name of Motacilla alba. The Latin genus name originally meant "little mover", but certain medieval writers thought it meant "wag-tail", giving rise to a new Latin word cilla for "tail". The specific epithet alba is Latin for "white".

Within the wagtail genus Motacilla, the White Wagtail's closest relatives appear to be other black-and-white wagtails such as the Japanese Wagtail, Motacilla grandis, and the White-browed Wagtail, Motacilla madaraspatensis, (and possibly the Mekong Wagtail, Motacilla samveasnae, the phylogenetic position of which is mysterious) with which it appears to form a superspecies. However mtDNA cytochrome b and NADH dehydrogenase subunit 2 sequence data suggests that the White Wagtail is itself polyphyletic or paraphyletic (i.e. the species is not itself a single coherent grouping). Other phylogenetic studies using mtDNA however suggest that there is considerable gene flow within the races and the resulting closeness makes Motacilla alba a single species. Some studies have suggested the existence of only two groups : the alboides group, with M. a. alboides, M. a. leucopsis and M. a. personata; and the alba group, with M. a. alba, M. a. yarrellii, M. a. baicalensis, M. a. ocularis, M. a. lugens, and M. a. subpersonata.