Eleven subspecies of the White Wagtail (Motacilla alba) are currently recognised and they all have slightly different plumages.
This is Motacilla alba alba, the nominate subspecies of the White Wagtail which occurs on the European continent and migrates down as far as Kenya.

First 4 photos: Pärnu Coastal Meadow Nature Reserve, Pärnu, Estonia, 22 April 2017
Last photo: Puhtulaid, Virtsu, Estonia, 22 April 2017