Identifying Sanderling Calidris alba

Sanderling Calidris alba, one of our favorite waders, as the name alba suggested, it is a very whitish species - very true for winter plumage when comparing to other Calidris species. It is a very chunky and medium-sized Calidris and the most confusing species should be Red-necked Stint Calidris ruficollis in both winter and summer plumage. However, Sanderling is clearly larger with a thicker bill, blacker carpal (difficult to see in field) and more importantly, lacks a hallux (three toes only) which is unique in Scolopacidae (again, difficult to see in field).

As seen below, one of the two friendly Sanderling which were molting to summer plumage seen in HK in April 2016.

Sanderling

In flight, the wing pattern is more contrasting than other Calidris, which shows a very striking white wingbar (form by white base of remiges and black tips of flight feathers and coverts), as the picture below retrieved from HBW.

upperwing pattern of Sanderling in HBW:

Van Gils, J., Wiersma, P. & Boesman, P. (2019). Sanderling (Calidris alba). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/53923 on 14 February 2019).

The feeding behavior of Sanderling can be distinctive too - wave running:

https://www.youtube.com/watch?v=5aV6piJC4Rc