Secondary intergradation of the Blue-headed and Grey-headed Wagtails (Motacilla f. flava L. and Motacilla f, thunbergi Billb.) in South Finland

Sammalisto, L. (1956). Secondary intergradation of the Blue-headed and Grey-headed Wagtails (Motacilla f. flava L. and Motacilla f, thunbergi Billb.) in South Finland. Ornis Fennica, 33(1), 1–19. Hämtad från https://ornisfennica.journal.fi/article/view/132588