Ecological and genetic heterogeneity of natural populations of the "yellow" wagtails (Passeriformes, Motacillidae) in the Middle Volga (Ulyanovsk area)

During the field seasons of 2012–2015, we conducted a joint study of the nested settlement of yellow Motacilla flava flava Linnaeus, 1758 white-ear Motacilla flava beema (Sykes, 1832), white-headed Motacilla flava leucocephala (Przewalski, 1887) and yellow-frontal Motacilla lutea (S.G. Gmelin, 1774) wagtails in the surroundings of Peschanoe Lake of Ulyanovsk region (Middle Volga), which live sympatrically in the European part of Russia. A subspecies of white-headed wagtail M. f. leucocephala is characterized by the maximum genetic distance (1306,67–1375,67), which corresponds to a species rank. Modern polytypical complex of M. flava, was probably formed in historical times through fan hybridization between the original forms of M. f. flava and M. lutea, when genetic differentiation and divergence played a leading role in the formation of space-time and the genetic structure of the Motacilla genus.