An early morning visit to Skaw produced a Great Northern Diver sat on the sea off the beach. A late afternoon visit to Baltasound and Haroldswick produced more Dunlin and Turnstone than of late and a Sanderling on Haroldswick beach with a Common Tern seen briefly fishing in Haroldswick Bay.
The white spots on the leading edge of the wing made this a rather eye-catching individual. Olsen & Larsson state that albinism is regular in the North Atlantic islands (as high as 2% in certain populations). Such birds show pale marginal and lesser coverts, creating a pale leading edge to the inner wing, and many also have paler areas elsewhere, especially a pale patch in the central and lower parts of the belly that today's bird also showed! The book even includes a photograph (Figure 76) of a similar individual photographed by Gordon Langsbury in Shetland in June 1993.
Sanderling and Turnstone crossing paths on Haroldswick beach
Being mid-late June it would seem likely the Sanderling is still heading north whereas the Turnstone might be heading south per The Birds of Shetland
Sanderling on Haroldswick Beach