Having heard a slightly unusual pipit call in flight that was similar to Rock Pipit but "thinner" and less emphatic I began examining every bird that I came across as I walked around the south-west tip of Benbecula. As I rounded the headland I noticed this striking bird feeding amongst the Rock Pipits gathered on the seaweed and rocks. It immediately struck me due to its strong supercilium, generally pale upper parts (compared with Rock Pipit), very distinctive supercilium and rather pale under parts. The wings bars were well defined and the streaking more clear cut than in the Rock Pipits (around 10 in all) present. The legs were also rather pale and the outer tail feathers appeared white. I was hoping for Water Pipit but the bird really didn't strike me as such. After some time I thought that this indivual may be a Scandinavian Rock Pipit that hadn't attained full winter plumage or was a very well-marked individual.
To me the upper parts appeared too olive-grey for a Water Pipit; the wing bars rather grey (rather than white); the under parts although quite distinctly streaked didn't appear clean enough for Water Pipit and there was some yellow suffusion on the belly.
Below are a series of photo of a British Rock Pipit taken on the same day.
I found one or two websites that showed the variation within both Water Pipit and Scandinavian Rock Pipit although such a strongly marked bird with grey upper parts at this time of year appeared a little odd. If you have any comments please feel free to get in touch: firstname.lastname@example.org