The delightful little Sanderling (Calidris alba), surely everyone's favourite Wader.
Not easy to keep up with as he races along the surf line. The trick is just to keep walking ahead of him and at the same distance and take photos as he reaches along side you. If you get just too close he will fly off and land again further along the surf line. Then you have to catch up, but surprisingly for such small legs he walks very quickly.