Pied Wagtail and White Wagtail
Motacilla alba yarrellii and Motacilla alba alba

The Pied Wagtail is the yarrellii race of the White Wagtail which occurs in Britain and Ireland, the rest of Europe has the alba race and is known as the White Wagtail. These can be seen in towns as well as coast and countryside. Outside of towns, they are often found near water, as are other wagtails. This first is a male Pied in winter plumage and the second is a female while three and four are of 1^st-winter birds.
 

  

  

  

This one is a male White Wagtail on migration from the continent, as can be seen from the clear demarcation between head and back and the whiter flanks.
 

  

1: Sandhurst, 09/02/2006.
2: South Mimms services, 26/02/2006.
3-4: Stowmarket, Suffolk, 17/12/2006.
5: Topsham, Devon, 10/01/2007.
6: Sutton Bingham Reservoir, 02/03/2007.
7-8: Hanningfield Reservoir, 17/09/2006.