Sanderling
Calidris alba
The sanderling is a small plump sandpiper, 18–20 cm (7–8 in) in length. Its weight ranges from 40–100 g (1+1⁄2–3+1⁄2 oz). The winter bird is very pale, almost white apart from a dark shoulder patch. This is the source of the specific name, alba, which is the Latin for "white". Later in the summer, the face and throat become brick-red. The juvenile bird is spangled black and white, and shows much more contrast than the adult.
ID text from Wikipedia, CC BY-SA 4.0
Semipalmated Sandpiper
Calidris pusilla
It is a small sandpiper, 15–18 centimetres (6–7 inches) long and weighing around 18–51.5 grams (0.63–1.82 ounces). Wingspan ranges from 13.8 to 14.6 in (35 to 37 cm). Adults have black legs and a short, stout, straight dark bill. The body is dark grey-brown on top and white underneath. The head and neck are tinged light grey-brown. This bird can be difficult to distinguish from other similar tiny shorebirds, in particular the western sandpiper; these are known collectively as "peeps" or "stints". Jonsson, Lars & Peter J.
ID text from Wikipedia, CC BY-SA 4.0
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