Hybridization of White <i>Motacilla alba</i> Linnaeus, 1758 and Masked <i>M. (a.) personata</i> Gould, 1861 Wagtails in the South of Siberia
We have made an attempt to estimate hybridization level between White Wagtail <i>Motacilla alba</i> and Masked Wagtail <i>M. (a.) personata</i> in their secondary contact zone in southern Siberia. Close examination of skins from several museums (<i>n</i> = 424) and authors' own (<i>n</i> = 347) collections supported by the molecular study of the control region of mtDNA revealed the occurrence of introgression process despite limited hybridization. New data on mate choice and breeding success in hybridization zone, habitat preference and mating demonstrations are presented. Possible reasons that limit hybridization in a situation when no reproductive isolation is visible are discussed.