Least Sandpiper
Calidris minutilla
This species has yellow-green legs and a short, thin, dark bill. Breeding adults are brown with dark brown streaks on top and white underneath. They have a light line above the eye and a dark crown. In winter, Least sandpipers are grey above. The juveniles are brightly patterned above with rufous colour and white mantle stripes. This bird can be difficult to distinguish from other similar tiny shorebirds; these are known collectively as "peeps" or "stints". In particular, least sandpiper is very similar to its Asian counterpart, long-toed stint.
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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