The Semipalmated Sandpiper is a small shorebird with a short bill. It breeds on Arctic tundra and winters along coasts farther south in the Americas.
It has small webs between its toes and a fairly short bill. Breeding, nonbreeding, and juvenile plumages differ in color and pattern.
It picks insects, small crustaceans, and other prey from mudflats and shallow water. It nests on Arctic tundra.
The male makes several shallow scrapes, often on rises near a pond. The female selects one and adds grass, moss and leaves. Four eggs hatch after 19–22 days, producing active, downy chicks.
It rapidly pecks and probes shallow water, finding amphipods, mollusks, marine worms and insects by touch and sight, including at night. In Canada’s Bay of Fundy it also slurps films of microorganisms.
The bill and legs are dark. Nonbreeding birds are grayish brown above with pale underparts and clean white flanks. White feather edges give juveniles neat back scaling. The tail is dark centrally and whitish at the sides.
An extinction-risk assessment has not been added yet.